Aside from some minor deviations noted below, an instance of this + * class represents a URI reference as defined by + * RFC 2396: Uniform + * Resource Identifiers (URI): Generic Syntax, amended by RFC 2732: Format for + * Literal IPv6 Addresses in URLs. The Literal IPv6 address format + * also supports scope_ids. The syntax and usage of scope_ids is described + * here. + * This class provides constructors for creating URI instances from + * their components or by parsing their string forms, methods for accessing the + * various components of an instance, and methods for normalizing, resolving, + * and relativizing URI instances. Instances of this class are immutable. + * + * + *
+ * [scheme:]scheme-specific-part[#fragment] + *+ * + * where square brackets [...] delineate optional components and the characters + * : and # stand for themselves. + * + *
An absolute URI specifies a scheme; a URI that is not absolute is + * said to be relative. URIs are also classified according to whether + * they are opaque or hierarchical. + * + *
An opaque URI is an absolute URI whose scheme-specific part does + * not begin with a slash character ('/'). Opaque URIs are not + * subject to further parsing. Some examples of opaque URIs are: + * + *
+ * + *+ *
+ * mailto:java-net@java.sun.com + * news:comp.lang.java + * urn:isbn:096139210x
A hierarchical URI is either an absolute URI whose + * scheme-specific part begins with a slash character, or a relative URI, that + * is, a URI that does not specify a scheme. Some examples of hierarchical + * URIs are: + * + *
+ * http://java.sun.com/j2se/1.3/+ * + *
+ * docs/guide/collections/designfaq.html#28
+ * ../../../demo/jfc/SwingSet2/src/SwingSet2.java
+ * file:///~/calendar + *
A hierarchical URI is subject to further parsing according to the syntax + * + *
+ * [scheme:][//authority][path][?query][#fragment] + *+ * + * where the characters :, /, + * ?, and # stand for themselves. The + * scheme-specific part of a hierarchical URI consists of the characters + * between the scheme and fragment components. + * + *
The authority component of a hierarchical URI is, if specified, either + * server-based or registry-based. A server-based authority + * parses according to the familiar syntax + * + *
+ * [user-info@]host[:port] + *+ * + * where the characters @ and : stand for + * themselves. Nearly all URI schemes currently in use are server-based. An + * authority component that does not parse in this way is considered to be + * registry-based. + * + *
The path component of a hierarchical URI is itself said to be absolute + * if it begins with a slash character ('/'); otherwise it is + * relative. The path of a hierarchical URI that is either absolute or + * specifies an authority is always absolute. + * + *
All told, then, a URI instance has the following nine components: + * + *
+ * + * In a given instance any particular component is either undefined or + * defined with a distinct value. Undefined string components are + * represented by null, while undefined integer components are + * represented by -1. A string component may be defined to have the + * empty string as its value; this is not equivalent to that component being + * undefined. + * + *+ *
+ * Component Type + * scheme String + * scheme-specific-part String + * authority String + * user-info String + * host String + * port int + * path String + * query String + * fragment String
Whether a particular component is or is not defined in an instance + * depends upon the type of the URI being represented. An absolute URI has a + * scheme component. An opaque URI has a scheme, a scheme-specific part, and + * possibly a fragment, but has no other components. A hierarchical URI always + * has a path (though it may be empty) and a scheme-specific-part (which at + * least contains the path), and may have any of the other components. If the + * authority component is present and is server-based then the host component + * will be defined and the user-information and port components may be defined. + * + * + *
Normalization is the process of removing unnecessary "." + * and ".." segments from the path component of a hierarchical URI. + * Each "." segment is simply removed. A ".." segment is + * removed only if it is preceded by a non-".." segment. + * Normalization has no effect upon opaque URIs. + * + *
Resolution is the process of resolving one URI against another, + * base URI. The resulting URI is constructed from components of both + * URIs in the manner specified by RFC 2396, taking components from the + * base URI for those not specified in the original. For hierarchical URIs, + * the path of the original is resolved against the path of the base and then + * normalized. The result, for example, of resolving + * + *
+ * docs/guide/collections/designfaq.html#28 (1) + *+ * + * against the base URI http://java.sun.com/j2se/1.3/ is the result + * URI + * + *
+ * http://java.sun.com/j2se/1.3/docs/guide/collections/designfaq.html#28 + *+ * + * Resolving the relative URI + * + *
+ * ../../../demo/jfc/SwingSet2/src/SwingSet2.java (2) + *+ * + * against this result yields, in turn, + * + *
+ * http://java.sun.com/j2se/1.3/demo/jfc/SwingSet2/src/SwingSet2.java + *+ * + * Resolution of both absolute and relative URIs, and of both absolute and + * relative paths in the case of hierarchical URIs, is supported. Resolving + * the URI file:///~calendar against any other URI simply yields the + * original URI, since it is absolute. Resolving the relative URI (2) above + * against the relative base URI (1) yields the normalized, but still relative, + * URI + * + *
+ * demo/jfc/SwingSet2/src/SwingSet2.java + *+ * + *
Relativization, finally, is the inverse of resolution: For any + * two normalized URIs u and v, + * + *
+ * u.relativize(u.resolve(v)).equals(v) and+ * + * This operation is often useful when constructing a document containing URIs + * that must be made relative to the base URI of the document wherever + * possible. For example, relativizing the URI + * + *
+ * u.resolve(u.relativize(v)).equals(v) .
+ *
+ * http://java.sun.com/j2se/1.3/docs/guide/index.html + *+ * + * against the base URI + * + *
+ * http://java.sun.com/j2se/1.3 + *+ * + * yields the relative URI docs/guide/index.html. + * + * + *
+ * + *+ *
+ * alpha + *The US-ASCII alphabetic characters, + * 'A' through 'Z' + * and 'a' through 'z' + * digit + *The US-ASCII decimal digit characters, + * '0' through '9' + * alphanum + *All alpha and digit characters + * unreserved + *All alphanum characters together with those in the string + * "_-!.~'()*" + * punct + *The characters in the string ",;:$&+=" + * reserved + *All punct characters together with those in the string + * "?/[]@" + * escaped + *Escaped octets, that is, triplets consisting of the percent + * character ('%') followed by two hexadecimal digits + * ('0'-'9', 'A'-'F', and + * 'a'-'f') + * other + *The Unicode characters that are not in the US-ASCII character set, + * are not control characters (according to the {@link + * java.lang.Character#isISOControl(char) Character.isISOControl} + * method), and are not space characters (according to the {@link + * java.lang.Character#isSpaceChar(char) Character.isSpaceChar} + * method) (Deviation from RFC 2396, which is + * limited to US-ASCII)
The set of all legal URI characters consists of + * the unreserved, reserved, escaped, and other + * characters. + * + * + *
To encode non-US-ASCII characters when a URI is required to + * conform strictly to RFC 2396 by not containing any other + * characters.
To quote characters that are otherwise illegal in a + * component. The user-info, path, query, and fragment components differ + * slightly in terms of which characters are considered legal and illegal. + *
A character is encoded by replacing it + * with the sequence of escaped octets that represent that character in the + * UTF-8 character set. The Euro currency symbol ('\u20AC'), + * for example, is encoded as "%E2%82%AC". (Deviation from + * RFC 2396, which does not specify any particular character + * set.)
An illegal character is quoted simply by + * encoding it. The space character, for example, is quoted by replacing it + * with "%20". UTF-8 contains US-ASCII, hence for US-ASCII + * characters this transformation has exactly the effect required by + * RFC 2396.
+ * A sequence of escaped octets is decoded by + * replacing it with the sequence of characters that it represents in the + * UTF-8 character set. UTF-8 contains US-ASCII, hence decoding has the + * effect of de-quoting any quoted US-ASCII characters as well as that of + * decoding any encoded non-US-ASCII characters. If a decoding error occurs + * when decoding the escaped octets then the erroneous octets are replaced by + * '\uFFFD', the Unicode replacement character.
The {@link #URI(java.lang.String) single-argument
+ * constructor} requires any illegal characters in its argument to be
+ * quoted and preserves any escaped octets and other characters that
+ * are present.
The {@link
+ * #URI(java.lang.String,java.lang.String,java.lang.String,int,java.lang.String,java.lang.String,java.lang.String)
+ * multi-argument constructors} quote illegal characters as
+ * required by the components in which they appear. The percent character
+ * ('%') is always quoted by these constructors. Any other
+ * characters are preserved.
The {@link #getRawUserInfo() getRawUserInfo}, {@link #getRawPath() + * getRawPath}, {@link #getRawQuery() getRawQuery}, {@link #getRawFragment() + * getRawFragment}, {@link #getRawAuthority() getRawAuthority}, and {@link + * #getRawSchemeSpecificPart() getRawSchemeSpecificPart} methods return the + * values of their corresponding components in raw form, without interpreting + * any escaped octets. The strings returned by these methods may contain + * both escaped octets and other characters, and will not contain any + * illegal characters.
The {@link #getUserInfo() getUserInfo}, {@link #getPath() + * getPath}, {@link #getQuery() getQuery}, {@link #getFragment() + * getFragment}, {@link #getAuthority() getAuthority}, and {@link + * #getSchemeSpecificPart() getSchemeSpecificPart} methods decode any escaped + * octets in their corresponding components. The strings returned by these + * methods may contain both other characters and illegal characters, + * and will not contain any escaped octets.
The {@link #toString() toString} method returns a URI string with + * all necessary quotation but which may contain other characters. + *
The {@link #toASCIIString() toASCIIString} method returns a fully + * quoted and encoded URI string that does not contain any other + * characters.
+ * new URI(u.toString()).equals(u) . + *+ * + * For any URI u that does not contain redundant syntax such as two + * slashes before an empty authority (as in file:///tmp/ ) or a + * colon following a host name but no port (as in + * http://java.sun.com: ), and that does not encode characters + * except those that must be quoted, the following identities also hold: + * + *
+ * new URI(u.getScheme(),+ * + * in all cases, + * + *
+ * u.getSchemeSpecificPart(),
+ * u.getFragment())
+ * .equals(u) + *
+ * new URI(u.getScheme(),+ * + * if u is hierarchical, and + * + *
+ * u.getUserInfo(), u.getAuthority(),
+ * u.getPath(), u.getQuery(),
+ * u.getFragment())
+ * .equals(u) + *
+ * new URI(u.getScheme(),+ * + * if u is hierarchical and has either no authority or a server-based + * authority. + * + * + *
+ * u.getUserInfo(), u.getHost(), u.getPort(),
+ * u.getPath(), u.getQuery(),
+ * u.getFragment())
+ * .equals(u) + *
The conceptual distinction between URIs and URLs is reflected in the + * differences between this class and the {@link URL} class. + * + *
An instance of this class represents a URI reference in the syntactic + * sense defined by RFC 2396. A URI may be either absolute or relative. + * A URI string is parsed according to the generic syntax without regard to the + * scheme, if any, that it specifies. No lookup of the host, if any, is + * performed, and no scheme-dependent stream handler is constructed. Equality, + * hashing, and comparison are defined strictly in terms of the character + * content of the instance. In other words, a URI instance is little more than + * a structured string that supports the syntactic, scheme-independent + * operations of comparison, normalization, resolution, and relativization. + * + *
An instance of the {@link URL} class, by contrast, represents the
+ * syntactic components of a URL together with some of the information required
+ * to access the resource that it describes. A URL must be absolute, that is,
+ * it must always specify a scheme. A URL string is parsed according to its
+ * scheme. A stream handler is always established for a URL, and in fact it is
+ * impossible to create a URL instance for a scheme for which no handler is
+ * available. Equality and hashing depend upon both the scheme and the
+ * Internet address of the host, if any; comparison is not defined. In other
+ * words, a URL is a structured string that supports the syntactic operation of
+ * resolution as well as the network I/O operations of looking up the host and
+ * opening a connection to the specified resource.
+ *
+ *
+ * @author Mark Reinhold
+ * @since 1.4
+ *
+ * @see RFC 2279: UTF-8, a
+ * transformation format of ISO 10646, This constructor parses the given string exactly as specified by the
+ * grammar in RFC 2396,
+ * Appendix A, except for the following deviations: An empty authority component is permitted as long as it is
+ * followed by a non-empty path, a query component, or a fragment
+ * component. This allows the parsing of URIs such as
+ * "file:///foo/bar", which seems to be the intent of
+ * RFC 2396 although the grammar does not permit it. If the
+ * authority component is empty then the user-information, host, and port
+ * components are undefined. Empty relative paths are permitted; this seems to be the
+ * intent of RFC 2396 although the grammar does not permit it. The
+ * primary consequence of this deviation is that a standalone fragment
+ * such as "#foo" parses as a relative URI with an empty path
+ * and the given fragment, and can be usefully resolved against a base URI.
+ *
+ * IPv4 addresses in host components are parsed rigorously, as
+ * specified by RFC 2732: Each
+ * element of a dotted-quad address must contain no more than three
+ * decimal digits. Each element is further constrained to have a value
+ * no greater than 255. Hostnames in host components that comprise only a single
+ * domain label are permitted to start with an alphanum
+ * character. This seems to be the intent of RFC 2396
+ * section 3.2.2 although the grammar does not permit it. The
+ * consequence of this deviation is that the authority component of a
+ * hierarchical URI such as s://123, will parse as a server-based
+ * authority. IPv6 addresses are permitted for the host component. An IPv6
+ * address must be enclosed in square brackets ('[' and
+ * ']') as specified by RFC 2732. The
+ * IPv6 address itself must parse according to RFC 2373. IPv6
+ * addresses are further constrained to describe no more than sixteen
+ * bytes of address information, a constraint implicit in RFC 2373
+ * but not expressible in the grammar. Characters in the other category are permitted wherever
+ * RFC 2396 permits escaped octets, that is, in the
+ * user-information, path, query, and fragment components, as well as in
+ * the authority component if the authority is registry-based. This
+ * allows URIs to contain Unicode characters beyond those in the US-ASCII
+ * character set. If a scheme is given then the path, if also given, must either be
+ * empty or begin with a slash character ('/'). Otherwise a
+ * component of the new URI may be left undefined by passing null
+ * for the corresponding parameter or, in the case of the port
+ * parameter, by passing -1.
+ *
+ * This constructor first builds a URI string from the given components
+ * according to the rules specified in RFC 2396,
+ * section 5.2, step 7: Initially, the result string is empty. If a scheme is given then it is appended to the result,
+ * followed by a colon character (':'). If user information, a host, or a port are given then the
+ * string "//" is appended. If user information is given then it is appended, followed by
+ * a commercial-at character ('@'). Any character not in the
+ * unreserved, punct, escaped, or other
+ * categories is quoted. If a host is given then it is appended. If the host is a
+ * literal IPv6 address but is not enclosed in square brackets
+ * ('[' and ']') then the square brackets are added.
+ * If a port number is given then a colon character
+ * (':') is appended, followed by the port number in decimal.
+ * If a path is given then it is appended. Any character not in
+ * the unreserved, punct, escaped, or other
+ * categories, and not equal to the slash character ('/') or the
+ * commercial-at character ('@'), is quoted. If a query is given then a question-mark character
+ * ('?') is appended, followed by the query. Any character that
+ * is not a legal URI character is quoted.
+ * Finally, if a fragment is given then a hash character
+ * ('#') is appended, followed by the fragment. Any character
+ * that is not a legal URI character is quoted. The resulting URI string is then parsed as if by invoking the {@link
+ * #URI(String)} constructor and then invoking the {@link
+ * #parseServerAuthority()} method upon the result; this may cause a {@link
+ * URISyntaxException} to be thrown. If a scheme is given then the path, if also given, must either be
+ * empty or begin with a slash character ('/'). Otherwise a
+ * component of the new URI may be left undefined by passing null
+ * for the corresponding parameter.
+ *
+ * This constructor first builds a URI string from the given components
+ * according to the rules specified in RFC 2396,
+ * section 5.2, step 7: Initially, the result string is empty. If a scheme is given then it is appended to the result,
+ * followed by a colon character (':'). If an authority is given then the string "//" is
+ * appended, followed by the authority. If the authority contains a
+ * literal IPv6 address then the address must be enclosed in square
+ * brackets ('[' and ']'). Any character not in the
+ * unreserved, punct, escaped, or other
+ * categories, and not equal to the commercial-at character
+ * ('@'), is quoted. If a path is given then it is appended. Any character not in
+ * the unreserved, punct, escaped, or other
+ * categories, and not equal to the slash character ('/') or the
+ * commercial-at character ('@'), is quoted. If a query is given then a question-mark character
+ * ('?') is appended, followed by the query. Any character that
+ * is not a legal URI character is quoted.
+ * Finally, if a fragment is given then a hash character
+ * ('#') is appended, followed by the fragment. Any character
+ * that is not a legal URI character is quoted. The resulting URI string is then parsed as if by invoking the {@link
+ * #URI(String)} constructor and then invoking the {@link
+ * #parseServerAuthority()} method upon the result; this may cause a {@link
+ * URISyntaxException} to be thrown. A component may be left undefined by passing null.
+ *
+ * This convenience constructor works as if by invoking the
+ * seven-argument constructor as follows:
+ *
+ * A component may be left undefined by passing null.
+ *
+ * This constructor first builds a URI in string form using the given
+ * components as follows: Initially, the result string is empty. If a scheme is given then it is appended to the result,
+ * followed by a colon character (':'). If a scheme-specific part is given then it is appended. Any
+ * character that is not a legal URI character
+ * is quoted. Finally, if a fragment is given then a hash character
+ * ('#') is appended to the string, followed by the fragment.
+ * Any character that is not a legal URI character is quoted. The resulting URI string is then parsed in order to create the new
+ * URI instance as if by invoking the {@link #URI(String)} constructor;
+ * this may cause a {@link URISyntaxException} to be thrown. This convenience factory method works as if by invoking the {@link
+ * #URI(String)} constructor; any {@link URISyntaxException} thrown by the
+ * constructor is caught and wrapped in a new {@link
+ * IllegalArgumentException} object, which is then thrown.
+ *
+ * This method is provided for use in situations where it is known that
+ * the given string is a legal URI, for example for URI constants declared
+ * within in a program, and so it would be considered a programming error
+ * for the string not to parse as such. The constructors, which throw
+ * {@link URISyntaxException} directly, should be used situations where a
+ * URI is being constructed from user input or from some other source that
+ * may be prone to errors. If this URI's authority component has already been recognized as
+ * being server-based then it will already have been parsed into
+ * user-information, host, and port components. In this case, or if this
+ * URI has no authority component, this method simply returns this URI.
+ *
+ * Otherwise this method attempts once more to parse the authority
+ * component into user-information, host, and port components, and throws
+ * an exception describing why the authority component could not be parsed
+ * in that way.
+ *
+ * This method is provided because the generic URI syntax specified in
+ * RFC 2396
+ * cannot always distinguish a malformed server-based authority from a
+ * legitimate registry-based authority. It must therefore treat some
+ * instances of the former as instances of the latter. The authority
+ * component in the URI string "//foo:bar", for example, is not a
+ * legal server-based authority but it is legal as a registry-based
+ * authority.
+ *
+ * In many common situations, for example when working URIs that are
+ * known to be either URNs or URLs, the hierarchical URIs being used will
+ * always be server-based. They therefore must either be parsed as such or
+ * treated as an error. In these cases a statement such as
+ *
+ * can be used to ensure that u always refers to a URI that, if
+ * it has an authority component, has a server-based authority with proper
+ * user-information, host, and port components. Invoking this method also
+ * ensures that if the authority could not be parsed in that way then an
+ * appropriate diagnostic message can be issued based upon the exception
+ * that is thrown. If this URI is opaque, or if its path is already in normal form,
+ * then this URI is returned. Otherwise a new URI is constructed that is
+ * identical to this URI except that its path is computed by normalizing
+ * this URI's path in a manner consistent with RFC 2396,
+ * section 5.2, step 6, sub-steps c through f; that is:
+ * All "." segments are removed. If a ".." segment is preceded by a non-".."
+ * segment then both of these segments are removed. This step is
+ * repeated until it is no longer applicable. If the path is relative, and if its first segment contains a
+ * colon character (':'), then a "." segment is
+ * prepended. This prevents a relative URI with a path such as
+ * "a:b/c/d" from later being re-parsed as an opaque URI with a
+ * scheme of "a" and a scheme-specific part of "b/c/d".
+ * (Deviation from RFC 2396) A normalized path will begin with one or more ".." segments
+ * if there were insufficient non-".." segments preceding them to
+ * allow their removal. A normalized path will begin with a "."
+ * segment if one was inserted by step 3 above. Otherwise, a normalized
+ * path will not contain any "." or ".." segments. If the given URI is already absolute, or if this URI is opaque, then
+ * the given URI is returned.
+ *
+ * If the given URI's fragment component is
+ * defined, its path component is empty, and its scheme, authority, and
+ * query components are undefined, then a URI with the given fragment but
+ * with all other components equal to those of this URI is returned. This
+ * allows a URI representing a standalone fragment reference, such as
+ * "#foo", to be usefully resolved against a base URI.
+ *
+ * Otherwise this method constructs a new hierarchical URI in a manner
+ * consistent with RFC 2396,
+ * section 5.2; that is: A new URI is constructed with this URI's scheme and the given
+ * URI's query and fragment components. If the given URI has an authority component then the new URI's
+ * authority and path are taken from the given URI. Otherwise the new URI's authority component is copied from
+ * this URI, and its path is computed as follows: If the given URI's path is absolute then the new URI's path
+ * is taken from the given URI. Otherwise the given URI's path is relative, and so the new
+ * URI's path is computed by resolving the path of the given URI
+ * against the path of this URI. This is done by concatenating all but
+ * the last segment of this URI's path, if any, with the given URI's
+ * path and then normalizing the result as if by invoking the {@link
+ * #normalize() normalize} method. The result of this method is absolute if, and only if, either this
+ * URI is absolute or the given URI is absolute. This convenience method works as if invoking it were equivalent to
+ * evaluating the expression {@link #resolve(java.net.URI)
+ * resolve}(URI.{@link #create(String) create}(str)). The relativization of the given URI against this URI is computed as
+ * follows: If either this URI or the given URI are opaque, or if the
+ * scheme and authority components of the two URIs are not identical, or
+ * if the path of this URI is not a prefix of the path of the given URI,
+ * then the given URI is returned. Otherwise a new relative hierarchical URI is constructed with
+ * query and fragment components taken from the given URI and with a path
+ * component computed by removing this URI's path from the beginning of
+ * the given URI's path. This convenience method works as if invoking it were equivalent to
+ * evaluating the expression new URL(this.toString()) after
+ * first checking that this URI is absolute. The scheme component of a URI, if defined, only contains characters
+ * in the alphanum category and in the string "-.+". A
+ * scheme always starts with an alpha character.
+ *
+ * The scheme component of a URI cannot contain escaped octets, hence this
+ * method does not perform any decoding.
+ *
+ * @return The scheme component of this URI,
+ * or null if the scheme is undefined
+ */
+ public String getScheme() {
+ return scheme;
+ }
+
+ /**
+ * Tells whether or not this URI is absolute.
+ *
+ * A URI is absolute if, and only if, it has a scheme component. A URI is opaque if, and only if, it is absolute and its
+ * scheme-specific part does not begin with a slash character ('/').
+ * An opaque URI has a scheme, a scheme-specific part, and possibly
+ * a fragment; all other components are undefined. The scheme-specific part of a URI only contains legal URI
+ * characters. The string returned by this method is equal to that returned by the
+ * {@link #getRawSchemeSpecificPart() getRawSchemeSpecificPart} method
+ * except that all sequences of escaped octets are decoded. The authority component of a URI, if defined, only contains the
+ * commercial-at character ('@') and characters in the
+ * unreserved, punct, escaped, and other
+ * categories. If the authority is server-based then it is further
+ * constrained to have valid user-information, host, and port
+ * components. The string returned by this method is equal to that returned by the
+ * {@link #getRawAuthority() getRawAuthority} method except that all
+ * sequences of escaped octets are decoded. The user-information component of a URI, if defined, only contains
+ * characters in the unreserved, punct, escaped, and
+ * other categories. The string returned by this method is equal to that returned by the
+ * {@link #getRawUserInfo() getRawUserInfo} method except that all
+ * sequences of escaped octets are decoded. The host component of a URI, if defined, will have one of the
+ * following forms: A domain name consisting of one or more labels
+ * separated by period characters ('.'), optionally followed by
+ * a period character. Each label consists of alphanum characters
+ * as well as hyphen characters ('-'), though hyphens never
+ * occur as the first or last characters in a label. The rightmost
+ * label of a domain name consisting of two or more labels, begins
+ * with an alpha character. A dotted-quad IPv4 address of the form
+ * digit+.digit+.digit+.digit+,
+ * where no digit sequence is longer than three characters and no
+ * sequence has a value larger than 255. An IPv6 address enclosed in square brackets ('[' and
+ * ']') and consisting of hexadecimal digits, colon characters
+ * (':'), and possibly an embedded IPv4 address. The full
+ * syntax of IPv6 addresses is specified in RFC 2373: IPv6
+ * Addressing Architecture. The port component of a URI, if defined, is a non-negative
+ * integer. The path component of a URI, if defined, only contains the slash
+ * character ('/'), the commercial-at character ('@'),
+ * and characters in the unreserved, punct, escaped,
+ * and other categories. The string returned by this method is equal to that returned by the
+ * {@link #getRawPath() getRawPath} method except that all sequences of
+ * escaped octets are decoded. The query component of a URI, if defined, only contains legal URI
+ * characters. The string returned by this method is equal to that returned by the
+ * {@link #getRawQuery() getRawQuery} method except that all sequences of
+ * escaped octets are decoded. The fragment component of a URI, if defined, only contains legal URI
+ * characters. The string returned by this method is equal to that returned by the
+ * {@link #getRawFragment() getRawFragment} method except that all
+ * sequences of escaped octets are decoded. If the given object is not a URI then this method immediately
+ * returns false.
+ *
+ * For two URIs to be considered equal requires that either both are
+ * opaque or both are hierarchical. Their schemes must either both be
+ * undefined or else be equal without regard to case. Their fragments
+ * must either both be undefined or else be equal.
+ *
+ * For two opaque URIs to be considered equal, their scheme-specific
+ * parts must be equal.
+ *
+ * For two hierarchical URIs to be considered equal, their paths must
+ * be equal and their queries must either both be undefined or else be
+ * equal. Their authorities must either both be undefined, or both be
+ * registry-based, or both be server-based. If their authorities are
+ * defined and are registry-based, then they must be equal. If their
+ * authorities are defined and are server-based, then their hosts must be
+ * equal without regard to case, their port numbers must be equal, and
+ * their user-information components must be equal.
+ *
+ * When testing the user-information, path, query, fragment, authority,
+ * or scheme-specific parts of two URIs for equality, the raw forms rather
+ * than the encoded forms of these components are compared and the
+ * hexadecimal digits of escaped octets are compared without regard to
+ * case.
+ *
+ * This method satisfies the general contract of the {@link
+ * java.lang.Object#equals(Object) Object.equals} method. When comparing corresponding components of two URIs, if one
+ * component is undefined but the other is defined then the first is
+ * considered to be less than the second. Unless otherwise noted, string
+ * components are ordered according to their natural, case-sensitive
+ * ordering as defined by the {@link java.lang.String#compareTo(Object)
+ * String.compareTo} method. String components that are subject to
+ * encoding are compared by comparing their raw forms rather than their
+ * encoded forms.
+ *
+ * The ordering of URIs is defined as follows: Two URIs with different schemes are ordered according the
+ * ordering of their schemes, without regard to case. A hierarchical URI is considered to be less than an opaque URI
+ * with an identical scheme. Two opaque URIs with identical schemes are ordered according
+ * to the ordering of their scheme-specific parts. Two opaque URIs with identical schemes and scheme-specific
+ * parts are ordered according to the ordering of their
+ * fragments. Two hierarchical URIs with identical schemes are ordered
+ * according to the ordering of their authority components: If both authority components are server-based then the URIs
+ * are ordered according to their user-information components; if these
+ * components are identical then the URIs are ordered according to the
+ * ordering of their hosts, without regard to case; if the hosts are
+ * identical then the URIs are ordered according to the ordering of
+ * their ports. If one or both authority components are registry-based then
+ * the URIs are ordered according to the ordering of their authority
+ * components. Finally, two hierarchical URIs with identical schemes and
+ * authority components are ordered according to the ordering of their
+ * paths; if their paths are identical then they are ordered according to
+ * the ordering of their queries; if the queries are identical then they
+ * are ordered according to the order of their fragments. This method satisfies the general contract of the {@link
+ * java.lang.Comparable#compareTo(Object) Comparable.compareTo}
+ * method. If this URI was created by invoking one of the constructors in this
+ * class then a string equivalent to the original input string, or to the
+ * string computed from the originally-given components, as appropriate, is
+ * returned. Otherwise this URI was created by normalization, resolution,
+ * or relativization, and so a string is constructed from this URI's
+ * components according to the rules specified in RFC 2396,
+ * section 5.2, step 7. If this URI does not contain any characters in the other
+ * category then an invocation of this method will return the same value as
+ * an invocation of the {@link #toString() toString} method. Otherwise
+ * this method works as if by invoking that method and then encoding the result. The only serializable field of a URI instance is its string
+ * field. That field is given a value, if it does not have one already,
+ * and then the {@link java.io.ObjectOutputStream#defaultWriteObject()}
+ * method of the given object-output stream is invoked. The {@link java.io.ObjectInputStream#defaultReadObject()} method is
+ * invoked to read the value of the string field. The result is
+ * then parsed in the usual way.
+ *
+ * @param is The object-input stream from which this object
+ * is being read
+ */
+ private void readObject(ObjectInputStream is)
+ throws ClassNotFoundException, IOException
+ {
+ port = -1; // Argh
+ is.defaultReadObject();
+ try {
+ new Parser(string).parse(false);
+ } catch (URISyntaxException x) {
+ IOException y = new InvalidObjectException("Invalid URI");
+ y.initCause(x);
+ throw y;
+ }
+ }
+
+
+ // -- End of public methods --
+
+
+ // -- Utility methods for string-field comparison and hashing --
+
+ // These methods return appropriate values for null string arguments,
+ // thereby simplifying the equals, hashCode, and compareTo methods.
+ //
+ // The case-ignoring methods should only be applied to strings whose
+ // characters are all known to be US-ASCII. Because of this restriction,
+ // these methods are faster than the similar methods in the String class.
+
+ // US-ASCII only
+ private static int toLower(char c) {
+ if ((c >= 'A') && (c <= 'Z'))
+ return c + ('a' - 'A');
+ return c;
+ }
+
+ private static boolean equal(String s, String t) {
+ if (s == t) return true;
+ if ((s != null) && (t != null)) {
+ if (s.length() != t.length())
+ return false;
+ if (s.indexOf('%') < 0)
+ return s.equals(t);
+ int n = s.length();
+ for (int i = 0; i < n;) {
+ char c = s.charAt(i);
+ char d = t.charAt(i);
+ if (c != '%') {
+ if (c != d)
+ return false;
+ i++;
+ continue;
+ }
+ i++;
+ if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
+ return false;
+ i++;
+ if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
+ return false;
+ i++;
+ }
+ return true;
+ }
+ return false;
+ }
+
+ // US-ASCII only
+ private static boolean equalIgnoringCase(String s, String t) {
+ if (s == t) return true;
+ if ((s != null) && (t != null)) {
+ int n = s.length();
+ if (t.length() != n)
+ return false;
+ for (int i = 0; i < n; i++) {
+ if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
+ return false;
+ }
+ return true;
+ }
+ return false;
+ }
+
+ private static int hash(int hash, String s) {
+ if (s == null) return hash;
+ return hash * 127 + s.hashCode();
+ }
+
+ // US-ASCII only
+ private static int hashIgnoringCase(int hash, String s) {
+ if (s == null) return hash;
+ int h = hash;
+ int n = s.length();
+ for (int i = 0; i < n; i++)
+ h = 31 * h + toLower(s.charAt(i));
+ return h;
+ }
+
+ private static int compare(String s, String t) {
+ if (s == t) return 0;
+ if (s != null) {
+ if (t != null)
+ return s.compareTo(t);
+ else
+ return +1;
+ } else {
+ return -1;
+ }
+ }
+
+ // US-ASCII only
+ private static int compareIgnoringCase(String s, String t) {
+ if (s == t) return 0;
+ if (s != null) {
+ if (t != null) {
+ int sn = s.length();
+ int tn = t.length();
+ int n = sn < tn ? sn : tn;
+ for (int i = 0; i < n; i++) {
+ int c = toLower(s.charAt(i)) - toLower(t.charAt(i));
+ if (c != 0)
+ return c;
+ }
+ return sn - tn;
+ }
+ return +1;
+ } else {
+ return -1;
+ }
+ }
+
+
+ // -- String construction --
+
+ // If a scheme is given then the path, if given, must be absolute
+ //
+ private static void checkPath(String s, String scheme, String path)
+ throws URISyntaxException
+ {
+ if (scheme != null) {
+ if ((path != null)
+ && ((path.length() > 0) && (path.charAt(0) != '/')))
+ throw new URISyntaxException(s,
+ "Relative path in absolute URI");
+ }
+ }
+
+ private void appendAuthority(StringBuffer sb,
+ String authority,
+ String userInfo,
+ String host,
+ int port)
+ {
+ if (host != null) {
+ sb.append("//");
+ if (userInfo != null) {
+ sb.append(quote(userInfo, L_USERINFO, H_USERINFO));
+ sb.append('@');
+ }
+ boolean needBrackets = ((host.indexOf(':') >= 0)
+ && !host.startsWith("[")
+ && !host.endsWith("]"));
+ if (needBrackets) sb.append('[');
+ sb.append(host);
+ if (needBrackets) sb.append(']');
+ if (port != -1) {
+ sb.append(':');
+ sb.append(port);
+ }
+ } else if (authority != null) {
+ sb.append("//");
+ if (authority.startsWith("[")) {
+ // authority should (but may not) contain an embedded IPv6 address
+ int end = authority.indexOf("]");
+ String doquote = authority, dontquote = "";
+ if (end != -1 && authority.indexOf(":") != -1) {
+ // the authority contains an IPv6 address
+ if (end == authority.length()) {
+ dontquote = authority;
+ doquote = "";
+ } else {
+ dontquote = authority.substring(0 , end + 1);
+ doquote = authority.substring(end + 1);
+ }
+ }
+ sb.append(dontquote);
+ sb.append(quote(doquote,
+ L_REG_NAME | L_SERVER,
+ H_REG_NAME | H_SERVER));
+ } else {
+ sb.append(quote(authority,
+ L_REG_NAME | L_SERVER,
+ H_REG_NAME | H_SERVER));
+ }
+ }
+ }
+
+ private void appendSchemeSpecificPart(StringBuffer sb,
+ String opaquePart,
+ String authority,
+ String userInfo,
+ String host,
+ int port,
+ String path,
+ String query)
+ {
+ if (opaquePart != null) {
+ /* check if SSP begins with an IPv6 address
+ * because we must not quote a literal IPv6 address
+ */
+ if (opaquePart.startsWith("//[")) {
+ int end = opaquePart.indexOf("]");
+ if (end != -1 && opaquePart.indexOf(":")!=-1) {
+ String doquote, dontquote;
+ if (end == opaquePart.length()) {
+ dontquote = opaquePart;
+ doquote = "";
+ } else {
+ dontquote = opaquePart.substring(0,end+1);
+ doquote = opaquePart.substring(end+1);
+ }
+ sb.append (dontquote);
+ sb.append(quote(doquote, L_URIC, H_URIC));
+ }
+ } else {
+ sb.append(quote(opaquePart, L_URIC, H_URIC));
+ }
+ } else {
+ appendAuthority(sb, authority, userInfo, host, port);
+ if (path != null)
+ sb.append(quote(path, L_PATH, H_PATH));
+ if (query != null) {
+ sb.append('?');
+ sb.append(quote(query, L_URIC, H_URIC));
+ }
+ }
+ }
+
+ private void appendFragment(StringBuffer sb, String fragment) {
+ if (fragment != null) {
+ sb.append('#');
+ sb.append(quote(fragment, L_URIC, H_URIC));
+ }
+ }
+
+ private String toString(String scheme,
+ String opaquePart,
+ String authority,
+ String userInfo,
+ String host,
+ int port,
+ String path,
+ String query,
+ String fragment)
+ {
+ StringBuffer sb = new StringBuffer();
+ if (scheme != null) {
+ sb.append(scheme);
+ sb.append(':');
+ }
+ appendSchemeSpecificPart(sb, opaquePart,
+ authority, userInfo, host, port,
+ path, query);
+ appendFragment(sb, fragment);
+ return sb.toString();
+ }
+
+ private void defineSchemeSpecificPart() {
+ if (schemeSpecificPart != null) return;
+ StringBuffer sb = new StringBuffer();
+ appendSchemeSpecificPart(sb, null, getAuthority(), getUserInfo(),
+ host, port, getPath(), getQuery());
+ if (sb.length() == 0) return;
+ schemeSpecificPart = sb.toString();
+ }
+
+ private void defineString() {
+ if (string != null) return;
+
+ StringBuffer sb = new StringBuffer();
+ if (scheme != null) {
+ sb.append(scheme);
+ sb.append(':');
+ }
+ if (isOpaque()) {
+ sb.append(schemeSpecificPart);
+ } else {
+ if (host != null) {
+ sb.append("//");
+ if (userInfo != null) {
+ sb.append(userInfo);
+ sb.append('@');
+ }
+ boolean needBrackets = ((host.indexOf(':') >= 0)
+ && !host.startsWith("[")
+ && !host.endsWith("]"));
+ if (needBrackets) sb.append('[');
+ sb.append(host);
+ if (needBrackets) sb.append(']');
+ if (port != -1) {
+ sb.append(':');
+ sb.append(port);
+ }
+ } else if (authority != null) {
+ sb.append("//");
+ sb.append(authority);
+ }
+ if (path != null)
+ sb.append(path);
+ if (query != null) {
+ sb.append('?');
+ sb.append(query);
+ }
+ }
+ if (fragment != null) {
+ sb.append('#');
+ sb.append(fragment);
+ }
+ string = sb.toString();
+ }
+
+
+ // -- Normalization, resolution, and relativization --
+
+ // RFC2396 5.2 (6)
+ private static String resolvePath(String base, String child,
+ boolean absolute)
+ {
+ int i = base.lastIndexOf('/');
+ int cn = child.length();
+ String path = "";
+
+ if (cn == 0) {
+ // 5.2 (6a)
+ if (i >= 0)
+ path = base.substring(0, i + 1);
+ } else {
+ StringBuffer sb = new StringBuffer(base.length() + cn);
+ // 5.2 (6a)
+ if (i >= 0)
+ sb.append(base.substring(0, i + 1));
+ // 5.2 (6b)
+ sb.append(child);
+ path = sb.toString();
+ }
+
+ // 5.2 (6c-f)
+ String np = normalize(path);
+
+ // 5.2 (6g): If the result is absolute but the path begins with "../",
+ // then we simply leave the path as-is
+
+ return np;
+ }
+
+ // RFC2396 5.2
+ private static URI resolve(URI base, URI child) {
+ // check if child if opaque first so that NPE is thrown
+ // if child is null.
+ if (child.isOpaque() || base.isOpaque())
+ return child;
+
+ // 5.2 (2): Reference to current document (lone fragment)
+ if ((child.scheme == null) && (child.authority == null)
+ && child.path.equals("") && (child.fragment != null)
+ && (child.query == null)) {
+ if ((base.fragment != null)
+ && child.fragment.equals(base.fragment)) {
+ return base;
+ }
+ URI ru = new URI();
+ ru.scheme = base.scheme;
+ ru.authority = base.authority;
+ ru.userInfo = base.userInfo;
+ ru.host = base.host;
+ ru.port = base.port;
+ ru.path = base.path;
+ ru.fragment = child.fragment;
+ ru.query = base.query;
+ return ru;
+ }
+
+ // 5.2 (3): Child is absolute
+ if (child.scheme != null)
+ return child;
+
+ URI ru = new URI(); // Resolved URI
+ ru.scheme = base.scheme;
+ ru.query = child.query;
+ ru.fragment = child.fragment;
+
+ // 5.2 (4): Authority
+ if (child.authority == null) {
+ ru.authority = base.authority;
+ ru.host = base.host;
+ ru.userInfo = base.userInfo;
+ ru.port = base.port;
+
+ String cp = (child.path == null) ? "" : child.path;
+ if ((cp.length() > 0) && (cp.charAt(0) == '/')) {
+ // 5.2 (5): Child path is absolute
+ ru.path = child.path;
+ } else {
+ // 5.2 (6): Resolve relative path
+ ru.path = resolvePath(base.path, cp, base.isAbsolute());
+ }
+ } else {
+ ru.authority = child.authority;
+ ru.host = child.host;
+ ru.userInfo = child.userInfo;
+ ru.host = child.host;
+ ru.port = child.port;
+ ru.path = child.path;
+ }
+
+ // 5.2 (7): Recombine (nothing to do here)
+ return ru;
+ }
+
+ // If the given URI's path is normal then return the URI;
+ // o.w., return a new URI containing the normalized path.
+ //
+ private static URI normalize(URI u) {
+ if (u.isOpaque() || (u.path == null) || (u.path.length() == 0))
+ return u;
+
+ String np = normalize(u.path);
+ if (np == u.path)
+ return u;
+
+ URI v = new URI();
+ v.scheme = u.scheme;
+ v.fragment = u.fragment;
+ v.authority = u.authority;
+ v.userInfo = u.userInfo;
+ v.host = u.host;
+ v.port = u.port;
+ v.path = np;
+ v.query = u.query;
+ return v;
+ }
+
+ // If both URIs are hierarchical, their scheme and authority components are
+ // identical, and the base path is a prefix of the child's path, then
+ // return a relative URI that, when resolved against the base, yields the
+ // child; otherwise, return the child.
+ //
+ private static URI relativize(URI base, URI child) {
+ // check if child if opaque first so that NPE is thrown
+ // if child is null.
+ if (child.isOpaque() || base.isOpaque())
+ return child;
+ if (!equalIgnoringCase(base.scheme, child.scheme)
+ || !equal(base.authority, child.authority))
+ return child;
+
+ String bp = normalize(base.path);
+ String cp = normalize(child.path);
+ if (!bp.equals(cp)) {
+ if (!bp.endsWith("/"))
+ bp = bp + "/";
+ if (!cp.startsWith(bp))
+ return child;
+ }
+
+ URI v = new URI();
+ v.path = cp.substring(bp.length());
+ v.query = child.query;
+ v.fragment = child.fragment;
+ return v;
+ }
+
+
+
+ // -- Path normalization --
+
+ // The following algorithm for path normalization avoids the creation of a
+ // string object for each segment, as well as the use of a string buffer to
+ // compute the final result, by using a single char array and editing it in
+ // place. The array is first split into segments, replacing each slash
+ // with '\0' and creating a segment-index array, each element of which is
+ // the index of the first char in the corresponding segment. We then walk
+ // through both arrays, removing ".", "..", and other segments as necessary
+ // by setting their entries in the index array to -1. Finally, the two
+ // arrays are used to rejoin the segments and compute the final result.
+ //
+ // This code is based upon src/solaris/native/java/io/canonicalize_md.c
+
+
+ // Check the given path to see if it might need normalization. A path
+ // might need normalization if it contains duplicate slashes, a "."
+ // segment, or a ".." segment. Return -1 if no further normalization is
+ // possible, otherwise return the number of segments found.
+ //
+ // This method takes a string argument rather than a char array so that
+ // this test can be performed without invoking path.toCharArray().
+ //
+ static private int needsNormalization(String path) {
+ boolean normal = true;
+ int ns = 0; // Number of segments
+ int end = path.length() - 1; // Index of last char in path
+ int p = 0; // Index of next char in path
+
+ // Skip initial slashes
+ while (p <= end) {
+ if (path.charAt(p) != '/') break;
+ p++;
+ }
+ if (p > 1) normal = false;
+
+ // Scan segments
+ while (p <= end) {
+
+ // Looking at "." or ".." ?
+ if ((path.charAt(p) == '.')
+ && ((p == end)
+ || ((path.charAt(p + 1) == '/')
+ || ((path.charAt(p + 1) == '.')
+ && ((p + 1 == end)
+ || (path.charAt(p + 2) == '/')))))) {
+ normal = false;
+ }
+ ns++;
+
+ // Find beginning of next segment
+ while (p <= end) {
+ if (path.charAt(p++) != '/')
+ continue;
+
+ // Skip redundant slashes
+ while (p <= end) {
+ if (path.charAt(p) != '/') break;
+ normal = false;
+ p++;
+ }
+
+ break;
+ }
+ }
+
+ return normal ? -1 : ns;
+ }
+
+
+ // Split the given path into segments, replacing slashes with nulls and
+ // filling in the given segment-index array.
+ //
+ // Preconditions:
+ // segs.length == Number of segments in path
+ //
+ // Postconditions:
+ // All slashes in path replaced by '\0'
+ // segs[i] == Index of first char in segment i (0 <= i < segs.length)
+ //
+ static private void split(char[] path, int[] segs) {
+ int end = path.length - 1; // Index of last char in path
+ int p = 0; // Index of next char in path
+ int i = 0; // Index of current segment
+
+ // Skip initial slashes
+ while (p <= end) {
+ if (path[p] != '/') break;
+ path[p] = '\0';
+ p++;
+ }
+
+ while (p <= end) {
+
+ // Note start of segment
+ segs[i++] = p++;
+
+ // Find beginning of next segment
+ while (p <= end) {
+ if (path[p++] != '/')
+ continue;
+ path[p - 1] = '\0';
+
+ // Skip redundant slashes
+ while (p <= end) {
+ if (path[p] != '/') break;
+ path[p++] = '\0';
+ }
+ break;
+ }
+ }
+
+ if (i != segs.length)
+ throw new InternalError(); // ASSERT
+ }
+
+
+ // Join the segments in the given path according to the given segment-index
+ // array, ignoring those segments whose index entries have been set to -1,
+ // and inserting slashes as needed. Return the length of the resulting
+ // path.
+ //
+ // Preconditions:
+ // segs[i] == -1 implies segment i is to be ignored
+ // path computed by split, as above, with '\0' having replaced '/'
+ //
+ // Postconditions:
+ // path[0] .. path[return value] == Resulting path
+ //
+ static private int join(char[] path, int[] segs) {
+ int ns = segs.length; // Number of segments
+ int end = path.length - 1; // Index of last char in path
+ int p = 0; // Index of next path char to write
+
+ if (path[p] == '\0') {
+ // Restore initial slash for absolute paths
+ path[p++] = '/';
+ }
+
+ for (int i = 0; i < ns; i++) {
+ int q = segs[i]; // Current segment
+ if (q == -1)
+ // Ignore this segment
+ continue;
+
+ if (p == q) {
+ // We're already at this segment, so just skip to its end
+ while ((p <= end) && (path[p] != '\0'))
+ p++;
+ if (p <= end) {
+ // Preserve trailing slash
+ path[p++] = '/';
+ }
+ } else if (p < q) {
+ // Copy q down to p
+ while ((q <= end) && (path[q] != '\0'))
+ path[p++] = path[q++];
+ if (q <= end) {
+ // Preserve trailing slash
+ path[p++] = '/';
+ }
+ } else
+ throw new InternalError(); // ASSERT false
+ }
+
+ return p;
+ }
+
+
+ // Remove "." segments from the given path, and remove segment pairs
+ // consisting of a non-".." segment followed by a ".." segment.
+ //
+ private static void removeDots(char[] path, int[] segs) {
+ int ns = segs.length;
+ int end = path.length - 1;
+
+ for (int i = 0; i < ns; i++) {
+ int dots = 0; // Number of dots found (0, 1, or 2)
+
+ // Find next occurrence of "." or ".."
+ do {
+ int p = segs[i];
+ if (path[p] == '.') {
+ if (p == end) {
+ dots = 1;
+ break;
+ } else if (path[p + 1] == '\0') {
+ dots = 1;
+ break;
+ } else if ((path[p + 1] == '.')
+ && ((p + 1 == end)
+ || (path[p + 2] == '\0'))) {
+ dots = 2;
+ break;
+ }
+ }
+ i++;
+ } while (i < ns);
+ if ((i > ns) || (dots == 0))
+ break;
+
+ if (dots == 1) {
+ // Remove this occurrence of "."
+ segs[i] = -1;
+ } else {
+ // If there is a preceding non-".." segment, remove both that
+ // segment and this occurrence of ".."; otherwise, leave this
+ // ".." segment as-is.
+ int j;
+ for (j = i - 1; j >= 0; j--) {
+ if (segs[j] != -1) break;
+ }
+ if (j >= 0) {
+ int q = segs[j];
+ if (!((path[q] == '.')
+ && (path[q + 1] == '.')
+ && (path[q + 2] == '\0'))) {
+ segs[i] = -1;
+ segs[j] = -1;
+ }
+ }
+ }
+ }
+ }
+
+
+ // DEVIATION: If the normalized path is relative, and if the first
+ // segment could be parsed as a scheme name, then prepend a "." segment
+ //
+ private static void maybeAddLeadingDot(char[] path, int[] segs) {
+
+ if (path[0] == '\0')
+ // The path is absolute
+ return;
+
+ int ns = segs.length;
+ int f = 0; // Index of first segment
+ while (f < ns) {
+ if (segs[f] >= 0)
+ break;
+ f++;
+ }
+ if ((f >= ns) || (f == 0))
+ // The path is empty, or else the original first segment survived,
+ // in which case we already know that no leading "." is needed
+ return;
+
+ int p = segs[f];
+ while ((p < path.length) && (path[p] != ':') && (path[p] != '\0')) p++;
+ if (p >= path.length || path[p] == '\0')
+ // No colon in first segment, so no "." needed
+ return;
+
+ // At this point we know that the first segment is unused,
+ // hence we can insert a "." segment at that position
+ path[0] = '.';
+ path[1] = '\0';
+ segs[0] = 0;
+ }
+
+
+ // Normalize the given path string. A normal path string has no empty
+ // segments (i.e., occurrences of "//"), no segments equal to ".", and no
+ // segments equal to ".." that are preceded by a segment not equal to "..".
+ // In contrast to Unix-style pathname normalization, for URI paths we
+ // always retain trailing slashes.
+ //
+ private static String normalize(String ps) {
+
+ // Does this path need normalization?
+ int ns = needsNormalization(ps); // Number of segments
+ if (ns < 0)
+ // Nope -- just return it
+ return ps;
+
+ char[] path = ps.toCharArray(); // Path in char-array form
+
+ // Split path into segments
+ int[] segs = new int[ns]; // Segment-index array
+ split(path, segs);
+
+ // Remove dots
+ removeDots(path, segs);
+
+ // Prevent scheme-name confusion
+ maybeAddLeadingDot(path, segs);
+
+ // Join the remaining segments and return the result
+ String s = new String(path, 0, join(path, segs));
+ if (s.equals(ps)) {
+ // string was already normalized
+ return ps;
+ }
+ return s;
+ }
+
+
+
+ // -- Character classes for parsing --
+
+ // RFC2396 precisely specifies which characters in the US-ASCII charset are
+ // permissible in the various components of a URI reference. We here
+ // define a set of mask pairs to aid in enforcing these restrictions. Each
+ // mask pair consists of two longs, a low mask and a high mask. Taken
+ // together they represent a 128-bit mask, where bit i is set iff the
+ // character with value i is permitted.
+ //
+ // This approach is more efficient than sequentially searching arrays of
+ // permitted characters. It could be made still more efficient by
+ // precompiling the mask information so that a character's presence in a
+ // given mask could be determined by a single table lookup.
+
+ // Compute the low-order mask for the characters in the given string
+ private static long lowMask(String chars) {
+ int n = chars.length();
+ long m = 0;
+ for (int i = 0; i < n; i++) {
+ char c = chars.charAt(i);
+ if (c < 64)
+ m |= (1L << c);
+ }
+ return m;
+ }
+
+ // Compute the high-order mask for the characters in the given string
+ private static long highMask(String chars) {
+ int n = chars.length();
+ long m = 0;
+ for (int i = 0; i < n; i++) {
+ char c = chars.charAt(i);
+ if ((c >= 64) && (c < 128))
+ m |= (1L << (c - 64));
+ }
+ return m;
+ }
+
+ // Compute a low-order mask for the characters
+ // between first and last, inclusive
+ private static long lowMask(char first, char last) {
+ long m = 0;
+ int f = Math.max(Math.min(first, 63), 0);
+ int l = Math.max(Math.min(last, 63), 0);
+ for (int i = f; i <= l; i++)
+ m |= 1L << i;
+ return m;
+ }
+
+ // Compute a high-order mask for the characters
+ // between first and last, inclusive
+ private static long highMask(char first, char last) {
+ long m = 0;
+ int f = Math.max(Math.min(first, 127), 64) - 64;
+ int l = Math.max(Math.min(last, 127), 64) - 64;
+ for (int i = f; i <= l; i++)
+ m |= 1L << i;
+ return m;
+ }
+
+ // Tell whether the given character is permitted by the given mask pair
+ private static boolean match(char c, long lowMask, long highMask) {
+ if (c == 0) // 0 doesn't have a slot in the mask. So, it never matches.
+ return false;
+ if (c < 64)
+ return ((1L << c) & lowMask) != 0;
+ if (c < 128)
+ return ((1L << (c - 64)) & highMask) != 0;
+ return false;
+ }
+
+ // Character-class masks, in reverse order from RFC2396 because
+ // initializers for static fields cannot make forward references.
+
+ // digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
+ // "8" | "9"
+ private static final long L_DIGIT = lowMask('0', '9');
+ private static final long H_DIGIT = 0L;
+
+ // upalpha = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" |
+ // "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" |
+ // "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z"
+ private static final long L_UPALPHA = 0L;
+ private static final long H_UPALPHA = highMask('A', 'Z');
+
+ // lowalpha = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" |
+ // "j" | "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" |
+ // "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z"
+ private static final long L_LOWALPHA = 0L;
+ private static final long H_LOWALPHA = highMask('a', 'z');
+
+ // alpha = lowalpha | upalpha
+ private static final long L_ALPHA = L_LOWALPHA | L_UPALPHA;
+ private static final long H_ALPHA = H_LOWALPHA | H_UPALPHA;
+
+ // alphanum = alpha | digit
+ private static final long L_ALPHANUM = L_DIGIT | L_ALPHA;
+ private static final long H_ALPHANUM = H_DIGIT | H_ALPHA;
+
+ // hex = digit | "A" | "B" | "C" | "D" | "E" | "F" |
+ // "a" | "b" | "c" | "d" | "e" | "f"
+ private static final long L_HEX = L_DIGIT;
+ private static final long H_HEX = highMask('A', 'F') | highMask('a', 'f');
+
+ // mark = "-" | "_" | "." | "!" | "~" | "*" | "'" |
+ // "(" | ")"
+ private static final long L_MARK = lowMask("-_.!~*'()");
+ private static final long H_MARK = highMask("-_.!~*'()");
+
+ // unreserved = alphanum | mark
+ private static final long L_UNRESERVED = L_ALPHANUM | L_MARK;
+ private static final long H_UNRESERVED = H_ALPHANUM | H_MARK;
+
+ // reserved = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" |
+ // "$" | "," | "[" | "]"
+ // Added per RFC2732: "[", "]"
+ private static final long L_RESERVED = lowMask(";/?:@&=+$,[]");
+ private static final long H_RESERVED = highMask(";/?:@&=+$,[]");
+
+ // The zero'th bit is used to indicate that escape pairs and non-US-ASCII
+ // characters are allowed; this is handled by the scanEscape method below.
+ private static final long L_ESCAPED = 1L;
+ private static final long H_ESCAPED = 0L;
+
+ // uric = reserved | unreserved | escaped
+ private static final long L_URIC = L_RESERVED | L_UNRESERVED | L_ESCAPED;
+ private static final long H_URIC = H_RESERVED | H_UNRESERVED | H_ESCAPED;
+
+ // pchar = unreserved | escaped |
+ // ":" | "@" | "&" | "=" | "+" | "$" | ","
+ private static final long L_PCHAR
+ = L_UNRESERVED | L_ESCAPED | lowMask(":@&=+$,");
+ private static final long H_PCHAR
+ = H_UNRESERVED | H_ESCAPED | highMask(":@&=+$,");
+
+ // All valid path characters
+ private static final long L_PATH = L_PCHAR | lowMask(";/");
+ private static final long H_PATH = H_PCHAR | highMask(";/");
+
+ // Dash, for use in domainlabel and toplabel
+ private static final long L_DASH = lowMask("-");
+ private static final long H_DASH = highMask("-");
+
+ // Dot, for use in hostnames
+ private static final long L_DOT = lowMask(".");
+ private static final long H_DOT = highMask(".");
+
+ // userinfo = *( unreserved | escaped |
+ // ";" | ":" | "&" | "=" | "+" | "$" | "," )
+ private static final long L_USERINFO
+ = L_UNRESERVED | L_ESCAPED | lowMask(";:&=+$,");
+ private static final long H_USERINFO
+ = H_UNRESERVED | H_ESCAPED | highMask(";:&=+$,");
+
+ // reg_name = 1*( unreserved | escaped | "$" | "," |
+ // ";" | ":" | "@" | "&" | "=" | "+" )
+ private static final long L_REG_NAME
+ = L_UNRESERVED | L_ESCAPED | lowMask("$,;:@&=+");
+ private static final long H_REG_NAME
+ = H_UNRESERVED | H_ESCAPED | highMask("$,;:@&=+");
+
+ // All valid characters for server-based authorities
+ private static final long L_SERVER
+ = L_USERINFO | L_ALPHANUM | L_DASH | lowMask(".:@[]");
+ private static final long H_SERVER
+ = H_USERINFO | H_ALPHANUM | H_DASH | highMask(".:@[]");
+
+ // Special case of server authority that represents an IPv6 address
+ // In this case, a % does not signify an escape sequence
+ private static final long L_SERVER_PERCENT
+ = L_SERVER | lowMask("%");
+ private static final long H_SERVER_PERCENT
+ = H_SERVER | highMask("%");
+ private static final long L_LEFT_BRACKET = lowMask("[");
+ private static final long H_LEFT_BRACKET = highMask("[");
+
+ // scheme = alpha *( alpha | digit | "+" | "-" | "." )
+ private static final long L_SCHEME = L_ALPHA | L_DIGIT | lowMask("+-.");
+ private static final long H_SCHEME = H_ALPHA | H_DIGIT | highMask("+-.");
+
+ // uric_no_slash = unreserved | escaped | ";" | "?" | ":" | "@" |
+ // "&" | "=" | "+" | "$" | ","
+ private static final long L_URIC_NO_SLASH
+ = L_UNRESERVED | L_ESCAPED | lowMask(";?:@&=+$,");
+ private static final long H_URIC_NO_SLASH
+ = H_UNRESERVED | H_ESCAPED | highMask(";?:@&=+$,");
+
+
+ // -- Escaping and encoding --
+
+ private final static char[] hexDigits = {
+ '0', '1', '2', '3', '4', '5', '6', '7',
+ '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+ };
+
+ private static void appendEscape(StringBuffer sb, byte b) {
+ sb.append('%');
+ sb.append(hexDigits[(b >> 4) & 0x0f]);
+ sb.append(hexDigits[(b >> 0) & 0x0f]);
+ }
+
+ private static void appendEncoded(StringBuffer sb, char c) {
+ ByteBuffer bb = null;
+ try {
+ bb = ThreadLocalCoders.encoderFor("UTF-8")
+ .encode(CharBuffer.wrap("" + c));
+ } catch (CharacterCodingException x) {
+ assert false;
+ }
+ while (bb.hasRemaining()) {
+ int b = bb.get() & 0xff;
+ if (b >= 0x80)
+ appendEscape(sb, (byte)b);
+ else
+ sb.append((char)b);
+ }
+ }
+
+ // Quote any characters in s that are not permitted
+ // by the given mask pair
+ //
+ private static String quote(String s, long lowMask, long highMask) {
+ int n = s.length();
+ StringBuffer sb = null;
+ boolean allowNonASCII = ((lowMask & L_ESCAPED) != 0);
+ for (int i = 0; i < s.length(); i++) {
+ char c = s.charAt(i);
+ if (c < '\u0080') {
+ if (!match(c, lowMask, highMask)) {
+ if (sb == null) {
+ sb = new StringBuffer();
+ sb.append(s.substring(0, i));
+ }
+ appendEscape(sb, (byte)c);
+ } else {
+ if (sb != null)
+ sb.append(c);
+ }
+ } else if (allowNonASCII
+ && (Character.isSpaceChar(c)
+ || Character.isISOControl(c))) {
+ if (sb == null) {
+ sb = new StringBuffer();
+ sb.append(s.substring(0, i));
+ }
+ appendEncoded(sb, c);
+ } else {
+ if (sb != null)
+ sb.append(c);
+ }
+ }
+ return (sb == null) ? s : sb.toString();
+ }
+
+ // Encodes all characters >= \u0080 into escaped, normalized UTF-8 octets,
+ // assuming that s is otherwise legal
+ //
+ private static String encode(String s) {
+ int n = s.length();
+ if (n == 0)
+ return s;
+
+ // First check whether we actually need to encode
+ for (int i = 0;;) {
+ if (s.charAt(i) >= '\u0080')
+ break;
+ if (++i >= n)
+ return s;
+ }
+
+ String ns = Normalizer.normalize(s, Normalizer.Form.NFC);
+ ByteBuffer bb = null;
+ try {
+ bb = ThreadLocalCoders.encoderFor("UTF-8")
+ .encode(CharBuffer.wrap(ns));
+ } catch (CharacterCodingException x) {
+ assert false;
+ }
+
+ StringBuffer sb = new StringBuffer();
+ while (bb.hasRemaining()) {
+ int b = bb.get() & 0xff;
+ if (b >= 0x80)
+ appendEscape(sb, (byte)b);
+ else
+ sb.append((char)b);
+ }
+ return sb.toString();
+ }
+
+ private static int decode(char c) {
+ if ((c >= '0') && (c <= '9'))
+ return c - '0';
+ if ((c >= 'a') && (c <= 'f'))
+ return c - 'a' + 10;
+ if ((c >= 'A') && (c <= 'F'))
+ return c - 'A' + 10;
+ assert false;
+ return -1;
+ }
+
+ private static byte decode(char c1, char c2) {
+ return (byte)( ((decode(c1) & 0xf) << 4)
+ | ((decode(c2) & 0xf) << 0));
+ }
+
+ // Evaluates all escapes in s, applying UTF-8 decoding if needed. Assumes
+ // that escapes are well-formed syntactically, i.e., of the form %XX. If a
+ // sequence of escaped octets is not valid UTF-8 then the erroneous octets
+ // are replaced with '\uFFFD'.
+ // Exception: any "%" found between "[]" is left alone. It is an IPv6 literal
+ // with a scope_id
+ //
+ private static String decode(String s) {
+ if (s == null)
+ return s;
+ int n = s.length();
+ if (n == 0)
+ return s;
+ if (s.indexOf('%') < 0)
+ return s;
+
+ StringBuffer sb = new StringBuffer(n);
+ ByteBuffer bb = ByteBuffer.allocate(n);
+ CharBuffer cb = CharBuffer.allocate(n);
+ CharsetDecoder dec = ThreadLocalCoders.decoderFor("UTF-8")
+ .onMalformedInput(CodingErrorAction.REPLACE)
+ .onUnmappableCharacter(CodingErrorAction.REPLACE);
+
+ // This is not horribly efficient, but it will do for now
+ char c = s.charAt(0);
+ boolean betweenBrackets = false;
+
+ for (int i = 0; i < n;) {
+ assert c == s.charAt(i); // Loop invariant
+ if (c == '[') {
+ betweenBrackets = true;
+ } else if (betweenBrackets && c == ']') {
+ betweenBrackets = false;
+ }
+ if (c != '%' || betweenBrackets) {
+ sb.append(c);
+ if (++i >= n)
+ break;
+ c = s.charAt(i);
+ continue;
+ }
+ bb.clear();
+ int ui = i;
+ for (;;) {
+ assert (n - i >= 2);
+ bb.put(decode(s.charAt(++i), s.charAt(++i)));
+ if (++i >= n)
+ break;
+ c = s.charAt(i);
+ if (c != '%')
+ break;
+ }
+ bb.flip();
+ cb.clear();
+ dec.reset();
+ CoderResult cr = dec.decode(bb, cb, true);
+ assert cr.isUnderflow();
+ cr = dec.flush(cb);
+ assert cr.isUnderflow();
+ sb.append(cb.flip().toString());
+ }
+
+ return sb.toString();
+ }
+
+
+ // -- Parsing --
+
+ // For convenience we wrap the input URI string in a new instance of the
+ // following internal class. This saves always having to pass the input
+ // string as an argument to each internal scan/parse method.
+
+ private class Parser {
+
+ private String input; // URI input string
+ private boolean requireServerAuthority = false;
+
+ Parser(String s) {
+ input = s;
+ string = s;
+ }
+
+ // -- Methods for throwing URISyntaxException in various ways --
+
+ private void fail(String reason) throws URISyntaxException {
+ throw new URISyntaxException(input, reason);
+ }
+
+ private void fail(String reason, int p) throws URISyntaxException {
+ throw new URISyntaxException(input, reason, p);
+ }
+
+ private void failExpecting(String expected, int p)
+ throws URISyntaxException
+ {
+ fail("Expected " + expected, p);
+ }
+
+ private void failExpecting(String expected, String prior, int p)
+ throws URISyntaxException
+ {
+ fail("Expected " + expected + " following " + prior, p);
+ }
+
+
+ // -- Simple access to the input string --
+
+ // Return a substring of the input string
+ //
+ private String substring(int start, int end) {
+ return input.substring(start, end);
+ }
+
+ // Return the char at position p,
+ // assuming that p < input.length()
+ //
+ private char charAt(int p) {
+ return input.charAt(p);
+ }
+
+ // Tells whether start < end and, if so, whether charAt(start) == c
+ //
+ private boolean at(int start, int end, char c) {
+ return (start < end) && (charAt(start) == c);
+ }
+
+ // Tells whether start + s.length() < end and, if so,
+ // whether the chars at the start position match s exactly
+ //
+ private boolean at(int start, int end, String s) {
+ int p = start;
+ int sn = s.length();
+ if (sn > end - p)
+ return false;
+ int i = 0;
+ while (i < sn) {
+ if (charAt(p++) != s.charAt(i)) {
+ break;
+ }
+ i++;
+ }
+ return (i == sn);
+ }
+
+
+ // -- Scanning --
+
+ // The various scan and parse methods that follow use a uniform
+ // convention of taking the current start position and end index as
+ // their first two arguments. The start is inclusive while the end is
+ // exclusive, just as in the String class, i.e., a start/end pair
+ // denotes the left-open interval [start, end) of the input string.
+ //
+ // These methods never proceed past the end position. They may return
+ // -1 to indicate outright failure, but more often they simply return
+ // the position of the first char after the last char scanned. Thus
+ // a typical idiom is
+ //
+ // int p = start;
+ // int q = scan(p, end, ...);
+ // if (q > p)
+ // // We scanned something
+ // ...;
+ // else if (q == p)
+ // // We scanned nothing
+ // ...;
+ // else if (q == -1)
+ // // Something went wrong
+ // ...;
+
+
+ // Scan a specific char: If the char at the given start position is
+ // equal to c, return the index of the next char; otherwise, return the
+ // start position.
+ //
+ private int scan(int start, int end, char c) {
+ if ((start < end) && (charAt(start) == c))
+ return start + 1;
+ return start;
+ }
+
+ // Scan forward from the given start position. Stop at the first char
+ // in the err string (in which case -1 is returned), or the first char
+ // in the stop string (in which case the index of the preceding char is
+ // returned), or the end of the input string (in which case the length
+ // of the input string is returned). May return the start position if
+ // nothing matches.
+ //
+ private int scan(int start, int end, String err, String stop) {
+ int p = start;
+ while (p < end) {
+ char c = charAt(p);
+ if (err.indexOf(c) >= 0)
+ return -1;
+ if (stop.indexOf(c) >= 0)
+ break;
+ p++;
+ }
+ return p;
+ }
+
+ // Scan a potential escape sequence, starting at the given position,
+ // with the given first char (i.e., charAt(start) == c).
+ //
+ // This method assumes that if escapes are allowed then visible
+ // non-US-ASCII chars are also allowed.
+ //
+ private int scanEscape(int start, int n, char first)
+ throws URISyntaxException
+ {
+ int p = start;
+ char c = first;
+ if (c == '%') {
+ // Process escape pair
+ if ((p + 3 <= n)
+ && match(charAt(p + 1), L_HEX, H_HEX)
+ && match(charAt(p + 2), L_HEX, H_HEX)) {
+ return p + 3;
+ }
+ fail("Malformed escape pair", p);
+ } else if ((c > 128)
+ && !Character.isSpaceChar(c)
+ && !Character.isISOControl(c)) {
+ // Allow unescaped but visible non-US-ASCII chars
+ return p + 1;
+ }
+ return p;
+ }
+
+ // Scan chars that match the given mask pair
+ //
+ private int scan(int start, int n, long lowMask, long highMask)
+ throws URISyntaxException
+ {
+ int p = start;
+ while (p < n) {
+ char c = charAt(p);
+ if (match(c, lowMask, highMask)) {
+ p++;
+ continue;
+ }
+ if ((lowMask & L_ESCAPED) != 0) {
+ int q = scanEscape(p, n, c);
+ if (q > p) {
+ p = q;
+ continue;
+ }
+ }
+ break;
+ }
+ return p;
+ }
+
+ // Check that each of the chars in [start, end) matches the given mask
+ //
+ private void checkChars(int start, int end,
+ long lowMask, long highMask,
+ String what)
+ throws URISyntaxException
+ {
+ int p = scan(start, end, lowMask, highMask);
+ if (p < end)
+ fail("Illegal character in " + what, p);
+ }
+
+ // Check that the char at position p matches the given mask
+ //
+ private void checkChar(int p,
+ long lowMask, long highMask,
+ String what)
+ throws URISyntaxException
+ {
+ checkChars(p, p + 1, lowMask, highMask, what);
+ }
+
+
+ // -- Parsing --
+
+ // [
RFC 2373: IPv6 Addressing
+ * Architecture,
RFC 2396: Uniform
+ * Resource Identifiers (URI): Generic Syntax,
RFC 2732: Format for
+ * Literal IPv6 Addresses in URLs,
URISyntaxException
+ */
+
+public final class URI
+ implements Comparable
+ *
+ *
+ *
+ * @param str The string to be parsed into a URI
+ *
+ * @throws NullPointerException
+ * If str is null
+ *
+ * @throws URISyntaxException
+ * If the given string violates RFC 2396, as augmented
+ * by the above deviations
+ */
+ public URI(String str) throws URISyntaxException {
+ new Parser(str).parse(false);
+ }
+
+ /**
+ * Constructs a hierarchical URI from the given components.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ * new {@link #URI(String, String, String, int, String, String, String)
+ * URI}(scheme, null, host, -1, path, null, fragment);
+ *
+ *
+ * @param scheme Scheme name
+ * @param host Host name
+ * @param path Path
+ * @param fragment Fragment
+ *
+ * @throws URISyntaxException
+ * If the URI string constructed from the given components
+ * violates RFC 2396
+ */
+ public URI(String scheme, String host, String path, String fragment)
+ throws URISyntaxException
+ {
+ this(scheme, null, host, -1, path, null, fragment);
+ }
+
+ /**
+ * Constructs a URI from the given components.
+ *
+ *
+ *
+ *
+ *
+ *
+ * URI u = new URI(str).parseServerAuthority();
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ * @param uri The URI to be relativized against this URI
+ * @return The resulting URI
+ *
+ * @throws NullPointerException
+ * If uri is null
+ */
+ public URI relativize(URI uri) {
+ return relativize(this, uri);
+ }
+
+ /**
+ * Constructs a URL from this URI.
+ *
+ *
+ *
+ *
+ *
+ * The host component of a URI cannot contain escaped octets, hence this
+ * method does not perform any decoding.
+ *
+ * @return The host component of this URI,
+ * or null if the host is undefined
+ */
+ public String getHost() {
+ return host;
+ }
+
+ /**
+ * Returns the port number of this URI.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *