rt/emul/compact/src/main/java/java/nio/charset/CharsetEncoder.java
branchjdk7-b147
changeset 1334 588d5bf7a560
child 1337 c794024954b5
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/rt/emul/compact/src/main/java/java/nio/charset/CharsetEncoder.java	Thu Oct 03 15:40:35 2013 +0200
     1.3 @@ -0,0 +1,972 @@
     1.4 +/*
     1.5 + * Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved.
     1.6 + * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
     1.7 + *
     1.8 + *
     1.9 + *
    1.10 + *
    1.11 + *
    1.12 + *
    1.13 + *
    1.14 + *
    1.15 + *
    1.16 + *
    1.17 + *
    1.18 + *
    1.19 + *
    1.20 + *
    1.21 + *
    1.22 + *
    1.23 + *
    1.24 + *
    1.25 + *
    1.26 + *
    1.27 + */
    1.28 +
    1.29 +// -- This file was mechanically generated: Do not edit! -- //
    1.30 +
    1.31 +package java.nio.charset;
    1.32 +
    1.33 +import java.nio.Buffer;
    1.34 +import java.nio.ByteBuffer;
    1.35 +import java.nio.CharBuffer;
    1.36 +import java.nio.BufferOverflowException;
    1.37 +import java.nio.BufferUnderflowException;
    1.38 +import java.lang.ref.WeakReference;
    1.39 +import java.nio.charset.CoderMalfunctionError;                  // javadoc
    1.40 +
    1.41 +
    1.42 +/**
    1.43 + * An engine that can transform a sequence of sixteen-bit Unicode characters into a sequence of
    1.44 + * bytes in a specific charset.
    1.45 + *
    1.46 + * <a name="steps">
    1.47 + *
    1.48 + * <p> The input character sequence is provided in a character buffer or a series
    1.49 + * of such buffers.  The output byte sequence is written to a byte buffer
    1.50 + * or a series of such buffers.  An encoder should always be used by making
    1.51 + * the following sequence of method invocations, hereinafter referred to as an
    1.52 + * <i>encoding operation</i>:
    1.53 + *
    1.54 + * <ol>
    1.55 + *
    1.56 + *   <li><p> Reset the encoder via the {@link #reset reset} method, unless it
    1.57 + *   has not been used before; </p></li>
    1.58 + *
    1.59 + *   <li><p> Invoke the {@link #encode encode} method zero or more times, as
    1.60 + *   long as additional input may be available, passing <tt>false</tt> for the
    1.61 + *   <tt>endOfInput</tt> argument and filling the input buffer and flushing the
    1.62 + *   output buffer between invocations; </p></li>
    1.63 + *
    1.64 + *   <li><p> Invoke the {@link #encode encode} method one final time, passing
    1.65 + *   <tt>true</tt> for the <tt>endOfInput</tt> argument; and then </p></li>
    1.66 + *
    1.67 + *   <li><p> Invoke the {@link #flush flush} method so that the encoder can
    1.68 + *   flush any internal state to the output buffer. </p></li>
    1.69 + *
    1.70 + * </ol>
    1.71 + *
    1.72 + * Each invocation of the {@link #encode encode} method will encode as many
    1.73 + * characters as possible from the input buffer, writing the resulting bytes
    1.74 + * to the output buffer.  The {@link #encode encode} method returns when more
    1.75 + * input is required, when there is not enough room in the output buffer, or
    1.76 + * when an encoding error has occurred.  In each case a {@link CoderResult}
    1.77 + * object is returned to describe the reason for termination.  An invoker can
    1.78 + * examine this object and fill the input buffer, flush the output buffer, or
    1.79 + * attempt to recover from an encoding error, as appropriate, and try again.
    1.80 + *
    1.81 + * <a name="ce">
    1.82 + *
    1.83 + * <p> There are two general types of encoding errors.  If the input character
    1.84 + * sequence is not a legal sixteen-bit Unicode sequence then the input is considered <i>malformed</i>.  If
    1.85 + * the input character sequence is legal but cannot be mapped to a valid
    1.86 + * byte sequence in the given charset then an <i>unmappable character</i> has been encountered.
    1.87 + *
    1.88 + * <a name="cae">
    1.89 + *
    1.90 + * <p> How an encoding error is handled depends upon the action requested for
    1.91 + * that type of error, which is described by an instance of the {@link
    1.92 + * CodingErrorAction} class.  The possible error actions are to {@link
    1.93 + * CodingErrorAction#IGNORE </code>ignore<code>} the erroneous input, {@link
    1.94 + * CodingErrorAction#REPORT </code>report<code>} the error to the invoker via
    1.95 + * the returned {@link CoderResult} object, or {@link CodingErrorAction#REPLACE
    1.96 + * </code>replace<code>} the erroneous input with the current value of the
    1.97 + * replacement byte array.  The replacement
    1.98 + *
    1.99 +
   1.100 + * is initially set to the encoder's default replacement, which often
   1.101 + * (but not always) has the initial value&nbsp;<tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>;
   1.102 +
   1.103 +
   1.104 +
   1.105 +
   1.106 + *
   1.107 + * its value may be changed via the {@link #replaceWith(byte[])
   1.108 + * replaceWith} method.
   1.109 + *
   1.110 + * <p> The default action for malformed-input and unmappable-character errors
   1.111 + * is to {@link CodingErrorAction#REPORT </code>report<code>} them.  The
   1.112 + * malformed-input error action may be changed via the {@link
   1.113 + * #onMalformedInput(CodingErrorAction) onMalformedInput} method; the
   1.114 + * unmappable-character action may be changed via the {@link
   1.115 + * #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter} method.
   1.116 + *
   1.117 + * <p> This class is designed to handle many of the details of the encoding
   1.118 + * process, including the implementation of error actions.  An encoder for a
   1.119 + * specific charset, which is a concrete subclass of this class, need only
   1.120 + * implement the abstract {@link #encodeLoop encodeLoop} method, which
   1.121 + * encapsulates the basic encoding loop.  A subclass that maintains internal
   1.122 + * state should, additionally, override the {@link #implFlush implFlush} and
   1.123 + * {@link #implReset implReset} methods.
   1.124 + *
   1.125 + * <p> Instances of this class are not safe for use by multiple concurrent
   1.126 + * threads.  </p>
   1.127 + *
   1.128 + *
   1.129 + * @author Mark Reinhold
   1.130 + * @author JSR-51 Expert Group
   1.131 + * @since 1.4
   1.132 + *
   1.133 + * @see ByteBuffer
   1.134 + * @see CharBuffer
   1.135 + * @see Charset
   1.136 + * @see CharsetDecoder
   1.137 + */
   1.138 +
   1.139 +public abstract class CharsetEncoder {
   1.140 +
   1.141 +    private final Charset charset;
   1.142 +    private final float averageBytesPerChar;
   1.143 +    private final float maxBytesPerChar;
   1.144 +
   1.145 +    private byte[] replacement;
   1.146 +    private CodingErrorAction malformedInputAction
   1.147 +        = CodingErrorAction.REPORT;
   1.148 +    private CodingErrorAction unmappableCharacterAction
   1.149 +        = CodingErrorAction.REPORT;
   1.150 +
   1.151 +    // Internal states
   1.152 +    //
   1.153 +    private static final int ST_RESET   = 0;
   1.154 +    private static final int ST_CODING  = 1;
   1.155 +    private static final int ST_END     = 2;
   1.156 +    private static final int ST_FLUSHED = 3;
   1.157 +
   1.158 +    private int state = ST_RESET;
   1.159 +
   1.160 +    private static String stateNames[]
   1.161 +        = { "RESET", "CODING", "CODING_END", "FLUSHED" };
   1.162 +
   1.163 +
   1.164 +    /**
   1.165 +     * Initializes a new encoder.  The new encoder will have the given
   1.166 +     * bytes-per-char and replacement values. </p>
   1.167 +     *
   1.168 +     * @param  averageBytesPerChar
   1.169 +     *         A positive float value indicating the expected number of
   1.170 +     *         bytes that will be produced for each input character
   1.171 +     *
   1.172 +     * @param  maxBytesPerChar
   1.173 +     *         A positive float value indicating the maximum number of
   1.174 +     *         bytes that will be produced for each input character
   1.175 +     *
   1.176 +     * @param  replacement
   1.177 +     *         The initial replacement; must not be <tt>null</tt>, must have
   1.178 +     *         non-zero length, must not be longer than maxBytesPerChar,
   1.179 +     *         and must be {@link #isLegalReplacement </code>legal<code>}
   1.180 +     *
   1.181 +     * @throws  IllegalArgumentException
   1.182 +     *          If the preconditions on the parameters do not hold
   1.183 +     */
   1.184 +    protected
   1.185 +    CharsetEncoder(Charset cs,
   1.186 +                   float averageBytesPerChar,
   1.187 +                   float maxBytesPerChar,
   1.188 +                   byte[] replacement)
   1.189 +    {
   1.190 +        this.charset = cs;
   1.191 +        if (averageBytesPerChar <= 0.0f)
   1.192 +            throw new IllegalArgumentException("Non-positive "
   1.193 +                                               + "averageBytesPerChar");
   1.194 +        if (maxBytesPerChar <= 0.0f)
   1.195 +            throw new IllegalArgumentException("Non-positive "
   1.196 +                                               + "maxBytesPerChar");
   1.197 +        if (!Charset.atBugLevel("1.4")) {
   1.198 +            if (averageBytesPerChar > maxBytesPerChar)
   1.199 +                throw new IllegalArgumentException("averageBytesPerChar"
   1.200 +                                                   + " exceeds "
   1.201 +                                                   + "maxBytesPerChar");
   1.202 +        }
   1.203 +        this.replacement = replacement;
   1.204 +        this.averageBytesPerChar = averageBytesPerChar;
   1.205 +        this.maxBytesPerChar = maxBytesPerChar;
   1.206 +        replaceWith(replacement);
   1.207 +    }
   1.208 +
   1.209 +    /**
   1.210 +     * Initializes a new encoder.  The new encoder will have the given
   1.211 +     * bytes-per-char values and its replacement will be the
   1.212 +     * byte array <tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>. </p>
   1.213 +     *
   1.214 +     * @param  averageBytesPerChar
   1.215 +     *         A positive float value indicating the expected number of
   1.216 +     *         bytes that will be produced for each input character
   1.217 +     *
   1.218 +     * @param  maxBytesPerChar
   1.219 +     *         A positive float value indicating the maximum number of
   1.220 +     *         bytes that will be produced for each input character
   1.221 +     *
   1.222 +     * @throws  IllegalArgumentException
   1.223 +     *          If the preconditions on the parameters do not hold
   1.224 +     */
   1.225 +    protected CharsetEncoder(Charset cs,
   1.226 +                             float averageBytesPerChar,
   1.227 +                             float maxBytesPerChar)
   1.228 +    {
   1.229 +        this(cs,
   1.230 +             averageBytesPerChar, maxBytesPerChar,
   1.231 +             new byte[] { (byte)'?' });
   1.232 +    }
   1.233 +
   1.234 +    /**
   1.235 +     * Returns the charset that created this encoder.  </p>
   1.236 +     *
   1.237 +     * @return  This encoder's charset
   1.238 +     */
   1.239 +    public final Charset charset() {
   1.240 +        return charset;
   1.241 +    }
   1.242 +
   1.243 +    /**
   1.244 +     * Returns this encoder's replacement value. </p>
   1.245 +     *
   1.246 +     * @return  This encoder's current replacement,
   1.247 +     *          which is never <tt>null</tt> and is never empty
   1.248 +     */
   1.249 +    public final byte[] replacement() {
   1.250 +        return replacement;
   1.251 +    }
   1.252 +
   1.253 +    /**
   1.254 +     * Changes this encoder's replacement value.
   1.255 +     *
   1.256 +     * <p> This method invokes the {@link #implReplaceWith implReplaceWith}
   1.257 +     * method, passing the new replacement, after checking that the new
   1.258 +     * replacement is acceptable.  </p>
   1.259 +     *
   1.260 +     * @param  newReplacement
   1.261 +     *
   1.262 +
   1.263 +
   1.264 +
   1.265 +
   1.266 +
   1.267 +     *         The new replacement; must not be <tt>null</tt>, must have
   1.268 +     *         non-zero length, must not be longer than the value returned by
   1.269 +     *         the {@link #maxBytesPerChar() maxBytesPerChar} method, and
   1.270 +     *         must be {@link #isLegalReplacement </code>legal<code>}
   1.271 +
   1.272 +     *
   1.273 +     * @return  This encoder
   1.274 +     *
   1.275 +     * @throws  IllegalArgumentException
   1.276 +     *          If the preconditions on the parameter do not hold
   1.277 +     */
   1.278 +    public final CharsetEncoder replaceWith(byte[] newReplacement) {
   1.279 +        if (newReplacement == null)
   1.280 +            throw new IllegalArgumentException("Null replacement");
   1.281 +        int len = newReplacement.length;
   1.282 +        if (len == 0)
   1.283 +            throw new IllegalArgumentException("Empty replacement");
   1.284 +        if (len > maxBytesPerChar)
   1.285 +            throw new IllegalArgumentException("Replacement too long");
   1.286 +
   1.287 +        if (!isLegalReplacement(newReplacement))
   1.288 +            throw new IllegalArgumentException("Illegal replacement");
   1.289 +
   1.290 +        this.replacement = newReplacement;
   1.291 +        implReplaceWith(newReplacement);
   1.292 +        return this;
   1.293 +    }
   1.294 +
   1.295 +    /**
   1.296 +     * Reports a change to this encoder's replacement value.
   1.297 +     *
   1.298 +     * <p> The default implementation of this method does nothing.  This method
   1.299 +     * should be overridden by encoders that require notification of changes to
   1.300 +     * the replacement.  </p>
   1.301 +     *
   1.302 +     * @param  newReplacement
   1.303 +     */
   1.304 +    protected void implReplaceWith(byte[] newReplacement) {
   1.305 +    }
   1.306 +
   1.307 +
   1.308 +
   1.309 +    private WeakReference<CharsetDecoder> cachedDecoder = null;
   1.310 +
   1.311 +    /**
   1.312 +     * Tells whether or not the given byte array is a legal replacement value
   1.313 +     * for this encoder.
   1.314 +     *
   1.315 +     * <p> A replacement is legal if, and only if, it is a legal sequence of
   1.316 +     * bytes in this encoder's charset; that is, it must be possible to decode
   1.317 +     * the replacement into one or more sixteen-bit Unicode characters.
   1.318 +     *
   1.319 +     * <p> The default implementation of this method is not very efficient; it
   1.320 +     * should generally be overridden to improve performance.  </p>
   1.321 +     *
   1.322 +     * @param  repl  The byte array to be tested
   1.323 +     *
   1.324 +     * @return  <tt>true</tt> if, and only if, the given byte array
   1.325 +     *          is a legal replacement value for this encoder
   1.326 +     */
   1.327 +    public boolean isLegalReplacement(byte[] repl) {
   1.328 +        WeakReference<CharsetDecoder> wr = cachedDecoder;
   1.329 +        CharsetDecoder dec = null;
   1.330 +        if ((wr == null) || ((dec = wr.get()) == null)) {
   1.331 +            dec = charset().newDecoder();
   1.332 +            dec.onMalformedInput(CodingErrorAction.REPORT);
   1.333 +            dec.onUnmappableCharacter(CodingErrorAction.REPORT);
   1.334 +            cachedDecoder = new WeakReference<CharsetDecoder>(dec);
   1.335 +        } else {
   1.336 +            dec.reset();
   1.337 +        }
   1.338 +        ByteBuffer bb = ByteBuffer.wrap(repl);
   1.339 +        CharBuffer cb = CharBuffer.allocate((int)(bb.remaining()
   1.340 +                                                  * dec.maxCharsPerByte()));
   1.341 +        CoderResult cr = dec.decode(bb, cb, true);
   1.342 +        return !cr.isError();
   1.343 +    }
   1.344 +
   1.345 +
   1.346 +
   1.347 +    /**
   1.348 +     * Returns this encoder's current action for malformed-input errors.  </p>
   1.349 +     *
   1.350 +     * @return The current malformed-input action, which is never <tt>null</tt>
   1.351 +     */
   1.352 +    public CodingErrorAction malformedInputAction() {
   1.353 +        return malformedInputAction;
   1.354 +    }
   1.355 +
   1.356 +    /**
   1.357 +     * Changes this encoder's action for malformed-input errors.  </p>
   1.358 +     *
   1.359 +     * <p> This method invokes the {@link #implOnMalformedInput
   1.360 +     * implOnMalformedInput} method, passing the new action.  </p>
   1.361 +     *
   1.362 +     * @param  newAction  The new action; must not be <tt>null</tt>
   1.363 +     *
   1.364 +     * @return  This encoder
   1.365 +     *
   1.366 +     * @throws IllegalArgumentException
   1.367 +     *         If the precondition on the parameter does not hold
   1.368 +     */
   1.369 +    public final CharsetEncoder onMalformedInput(CodingErrorAction newAction) {
   1.370 +        if (newAction == null)
   1.371 +            throw new IllegalArgumentException("Null action");
   1.372 +        malformedInputAction = newAction;
   1.373 +        implOnMalformedInput(newAction);
   1.374 +        return this;
   1.375 +    }
   1.376 +
   1.377 +    /**
   1.378 +     * Reports a change to this encoder's malformed-input action.
   1.379 +     *
   1.380 +     * <p> The default implementation of this method does nothing.  This method
   1.381 +     * should be overridden by encoders that require notification of changes to
   1.382 +     * the malformed-input action.  </p>
   1.383 +     */
   1.384 +    protected void implOnMalformedInput(CodingErrorAction newAction) { }
   1.385 +
   1.386 +    /**
   1.387 +     * Returns this encoder's current action for unmappable-character errors.
   1.388 +     * </p>
   1.389 +     *
   1.390 +     * @return The current unmappable-character action, which is never
   1.391 +     *         <tt>null</tt>
   1.392 +     */
   1.393 +    public CodingErrorAction unmappableCharacterAction() {
   1.394 +        return unmappableCharacterAction;
   1.395 +    }
   1.396 +
   1.397 +    /**
   1.398 +     * Changes this encoder's action for unmappable-character errors.
   1.399 +     *
   1.400 +     * <p> This method invokes the {@link #implOnUnmappableCharacter
   1.401 +     * implOnUnmappableCharacter} method, passing the new action.  </p>
   1.402 +     *
   1.403 +     * @param  newAction  The new action; must not be <tt>null</tt>
   1.404 +     *
   1.405 +     * @return  This encoder
   1.406 +     *
   1.407 +     * @throws IllegalArgumentException
   1.408 +     *         If the precondition on the parameter does not hold
   1.409 +     */
   1.410 +    public final CharsetEncoder onUnmappableCharacter(CodingErrorAction
   1.411 +                                                      newAction)
   1.412 +    {
   1.413 +        if (newAction == null)
   1.414 +            throw new IllegalArgumentException("Null action");
   1.415 +        unmappableCharacterAction = newAction;
   1.416 +        implOnUnmappableCharacter(newAction);
   1.417 +        return this;
   1.418 +    }
   1.419 +
   1.420 +    /**
   1.421 +     * Reports a change to this encoder's unmappable-character action.
   1.422 +     *
   1.423 +     * <p> The default implementation of this method does nothing.  This method
   1.424 +     * should be overridden by encoders that require notification of changes to
   1.425 +     * the unmappable-character action.  </p>
   1.426 +     */
   1.427 +    protected void implOnUnmappableCharacter(CodingErrorAction newAction) { }
   1.428 +
   1.429 +    /**
   1.430 +     * Returns the average number of bytes that will be produced for each
   1.431 +     * character of input.  This heuristic value may be used to estimate the size
   1.432 +     * of the output buffer required for a given input sequence. </p>
   1.433 +     *
   1.434 +     * @return  The average number of bytes produced
   1.435 +     *          per character of input
   1.436 +     */
   1.437 +    public final float averageBytesPerChar() {
   1.438 +        return averageBytesPerChar;
   1.439 +    }
   1.440 +
   1.441 +    /**
   1.442 +     * Returns the maximum number of bytes that will be produced for each
   1.443 +     * character of input.  This value may be used to compute the worst-case size
   1.444 +     * of the output buffer required for a given input sequence. </p>
   1.445 +     *
   1.446 +     * @return  The maximum number of bytes that will be produced per
   1.447 +     *          character of input
   1.448 +     */
   1.449 +    public final float maxBytesPerChar() {
   1.450 +        return maxBytesPerChar;
   1.451 +    }
   1.452 +
   1.453 +    /**
   1.454 +     * Encodes as many characters as possible from the given input buffer,
   1.455 +     * writing the results to the given output buffer.
   1.456 +     *
   1.457 +     * <p> The buffers are read from, and written to, starting at their current
   1.458 +     * positions.  At most {@link Buffer#remaining in.remaining()} characters
   1.459 +     * will be read and at most {@link Buffer#remaining out.remaining()}
   1.460 +     * bytes will be written.  The buffers' positions will be advanced to
   1.461 +     * reflect the characters read and the bytes written, but their marks and
   1.462 +     * limits will not be modified.
   1.463 +     *
   1.464 +     * <p> In addition to reading characters from the input buffer and writing
   1.465 +     * bytes to the output buffer, this method returns a {@link CoderResult}
   1.466 +     * object to describe its reason for termination:
   1.467 +     *
   1.468 +     * <ul>
   1.469 +     *
   1.470 +     *   <li><p> {@link CoderResult#UNDERFLOW} indicates that as much of the
   1.471 +     *   input buffer as possible has been encoded.  If there is no further
   1.472 +     *   input then the invoker can proceed to the next step of the
   1.473 +     *   <a href="#steps">encoding operation</a>.  Otherwise this method
   1.474 +     *   should be invoked again with further input.  </p></li>
   1.475 +     *
   1.476 +     *   <li><p> {@link CoderResult#OVERFLOW} indicates that there is
   1.477 +     *   insufficient space in the output buffer to encode any more characters.
   1.478 +     *   This method should be invoked again with an output buffer that has
   1.479 +     *   more {@linkplain Buffer#remaining remaining} bytes. This is
   1.480 +     *   typically done by draining any encoded bytes from the output
   1.481 +     *   buffer.  </p></li>
   1.482 +     *
   1.483 +     *   <li><p> A {@link CoderResult#malformedForLength
   1.484 +     *   </code>malformed-input<code>} result indicates that a malformed-input
   1.485 +     *   error has been detected.  The malformed characters begin at the input
   1.486 +     *   buffer's (possibly incremented) position; the number of malformed
   1.487 +     *   characters may be determined by invoking the result object's {@link
   1.488 +     *   CoderResult#length() length} method.  This case applies only if the
   1.489 +     *   {@link #onMalformedInput </code>malformed action<code>} of this encoder
   1.490 +     *   is {@link CodingErrorAction#REPORT}; otherwise the malformed input
   1.491 +     *   will be ignored or replaced, as requested.  </p></li>
   1.492 +     *
   1.493 +     *   <li><p> An {@link CoderResult#unmappableForLength
   1.494 +     *   </code>unmappable-character<code>} result indicates that an
   1.495 +     *   unmappable-character error has been detected.  The characters that
   1.496 +     *   encode the unmappable character begin at the input buffer's (possibly
   1.497 +     *   incremented) position; the number of such characters may be determined
   1.498 +     *   by invoking the result object's {@link CoderResult#length() length}
   1.499 +     *   method.  This case applies only if the {@link #onUnmappableCharacter
   1.500 +     *   </code>unmappable action<code>} of this encoder is {@link
   1.501 +     *   CodingErrorAction#REPORT}; otherwise the unmappable character will be
   1.502 +     *   ignored or replaced, as requested.  </p></li>
   1.503 +     *
   1.504 +     * </ul>
   1.505 +     *
   1.506 +     * In any case, if this method is to be reinvoked in the same encoding
   1.507 +     * operation then care should be taken to preserve any characters remaining
   1.508 +     * in the input buffer so that they are available to the next invocation.
   1.509 +     *
   1.510 +     * <p> The <tt>endOfInput</tt> parameter advises this method as to whether
   1.511 +     * the invoker can provide further input beyond that contained in the given
   1.512 +     * input buffer.  If there is a possibility of providing additional input
   1.513 +     * then the invoker should pass <tt>false</tt> for this parameter; if there
   1.514 +     * is no possibility of providing further input then the invoker should
   1.515 +     * pass <tt>true</tt>.  It is not erroneous, and in fact it is quite
   1.516 +     * common, to pass <tt>false</tt> in one invocation and later discover that
   1.517 +     * no further input was actually available.  It is critical, however, that
   1.518 +     * the final invocation of this method in a sequence of invocations always
   1.519 +     * pass <tt>true</tt> so that any remaining unencoded input will be treated
   1.520 +     * as being malformed.
   1.521 +     *
   1.522 +     * <p> This method works by invoking the {@link #encodeLoop encodeLoop}
   1.523 +     * method, interpreting its results, handling error conditions, and
   1.524 +     * reinvoking it as necessary.  </p>
   1.525 +     *
   1.526 +     *
   1.527 +     * @param  in
   1.528 +     *         The input character buffer
   1.529 +     *
   1.530 +     * @param  out
   1.531 +     *         The output byte buffer
   1.532 +     *
   1.533 +     * @param  endOfInput
   1.534 +     *         <tt>true</tt> if, and only if, the invoker can provide no
   1.535 +     *         additional input characters beyond those in the given buffer
   1.536 +     *
   1.537 +     * @return  A coder-result object describing the reason for termination
   1.538 +     *
   1.539 +     * @throws  IllegalStateException
   1.540 +     *          If an encoding operation is already in progress and the previous
   1.541 +     *          step was an invocation neither of the {@link #reset reset}
   1.542 +     *          method, nor of this method with a value of <tt>false</tt> for
   1.543 +     *          the <tt>endOfInput</tt> parameter, nor of this method with a
   1.544 +     *          value of <tt>true</tt> for the <tt>endOfInput</tt> parameter
   1.545 +     *          but a return value indicating an incomplete encoding operation
   1.546 +     *
   1.547 +     * @throws  CoderMalfunctionError
   1.548 +     *          If an invocation of the encodeLoop method threw
   1.549 +     *          an unexpected exception
   1.550 +     */
   1.551 +    public final CoderResult encode(CharBuffer in, ByteBuffer out,
   1.552 +                                    boolean endOfInput)
   1.553 +    {
   1.554 +        int newState = endOfInput ? ST_END : ST_CODING;
   1.555 +        if ((state != ST_RESET) && (state != ST_CODING)
   1.556 +            && !(endOfInput && (state == ST_END)))
   1.557 +            throwIllegalStateException(state, newState);
   1.558 +        state = newState;
   1.559 +
   1.560 +        for (;;) {
   1.561 +
   1.562 +            CoderResult cr;
   1.563 +            try {
   1.564 +                cr = encodeLoop(in, out);
   1.565 +            } catch (BufferUnderflowException x) {
   1.566 +                throw new CoderMalfunctionError(x);
   1.567 +            } catch (BufferOverflowException x) {
   1.568 +                throw new CoderMalfunctionError(x);
   1.569 +            }
   1.570 +
   1.571 +            if (cr.isOverflow())
   1.572 +                return cr;
   1.573 +
   1.574 +            if (cr.isUnderflow()) {
   1.575 +                if (endOfInput && in.hasRemaining()) {
   1.576 +                    cr = CoderResult.malformedForLength(in.remaining());
   1.577 +                    // Fall through to malformed-input case
   1.578 +                } else {
   1.579 +                    return cr;
   1.580 +                }
   1.581 +            }
   1.582 +
   1.583 +            CodingErrorAction action = null;
   1.584 +            if (cr.isMalformed())
   1.585 +                action = malformedInputAction;
   1.586 +            else if (cr.isUnmappable())
   1.587 +                action = unmappableCharacterAction;
   1.588 +            else
   1.589 +                assert false : cr.toString();
   1.590 +
   1.591 +            if (action == CodingErrorAction.REPORT)
   1.592 +                return cr;
   1.593 +
   1.594 +            if (action == CodingErrorAction.REPLACE) {
   1.595 +                if (out.remaining() < replacement.length)
   1.596 +                    return CoderResult.OVERFLOW;
   1.597 +                out.put(replacement);
   1.598 +            }
   1.599 +
   1.600 +            if ((action == CodingErrorAction.IGNORE)
   1.601 +                || (action == CodingErrorAction.REPLACE)) {
   1.602 +                // Skip erroneous input either way
   1.603 +                in.position(in.position() + cr.length());
   1.604 +                continue;
   1.605 +            }
   1.606 +
   1.607 +            assert false;
   1.608 +        }
   1.609 +
   1.610 +    }
   1.611 +
   1.612 +    /**
   1.613 +     * Flushes this encoder.
   1.614 +     *
   1.615 +     * <p> Some encoders maintain internal state and may need to write some
   1.616 +     * final bytes to the output buffer once the overall input sequence has
   1.617 +     * been read.
   1.618 +     *
   1.619 +     * <p> Any additional output is written to the output buffer beginning at
   1.620 +     * its current position.  At most {@link Buffer#remaining out.remaining()}
   1.621 +     * bytes will be written.  The buffer's position will be advanced
   1.622 +     * appropriately, but its mark and limit will not be modified.
   1.623 +     *
   1.624 +     * <p> If this method completes successfully then it returns {@link
   1.625 +     * CoderResult#UNDERFLOW}.  If there is insufficient room in the output
   1.626 +     * buffer then it returns {@link CoderResult#OVERFLOW}.  If this happens
   1.627 +     * then this method must be invoked again, with an output buffer that has
   1.628 +     * more room, in order to complete the current <a href="#steps">encoding
   1.629 +     * operation</a>.
   1.630 +     *
   1.631 +     * <p> If this encoder has already been flushed then invoking this method
   1.632 +     * has no effect.
   1.633 +     *
   1.634 +     * <p> This method invokes the {@link #implFlush implFlush} method to
   1.635 +     * perform the actual flushing operation.  </p>
   1.636 +     *
   1.637 +     * @param  out
   1.638 +     *         The output byte buffer
   1.639 +     *
   1.640 +     * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
   1.641 +     *          {@link CoderResult#OVERFLOW}
   1.642 +     *
   1.643 +     * @throws  IllegalStateException
   1.644 +     *          If the previous step of the current encoding operation was an
   1.645 +     *          invocation neither of the {@link #flush flush} method nor of
   1.646 +     *          the three-argument {@link
   1.647 +     *          #encode(CharBuffer,ByteBuffer,boolean) encode} method
   1.648 +     *          with a value of <tt>true</tt> for the <tt>endOfInput</tt>
   1.649 +     *          parameter
   1.650 +     */
   1.651 +    public final CoderResult flush(ByteBuffer out) {
   1.652 +        if (state == ST_END) {
   1.653 +            CoderResult cr = implFlush(out);
   1.654 +            if (cr.isUnderflow())
   1.655 +                state = ST_FLUSHED;
   1.656 +            return cr;
   1.657 +        }
   1.658 +
   1.659 +        if (state != ST_FLUSHED)
   1.660 +            throwIllegalStateException(state, ST_FLUSHED);
   1.661 +
   1.662 +        return CoderResult.UNDERFLOW; // Already flushed
   1.663 +    }
   1.664 +
   1.665 +    /**
   1.666 +     * Flushes this encoder.
   1.667 +     *
   1.668 +     * <p> The default implementation of this method does nothing, and always
   1.669 +     * returns {@link CoderResult#UNDERFLOW}.  This method should be overridden
   1.670 +     * by encoders that may need to write final bytes to the output buffer
   1.671 +     * once the entire input sequence has been read. </p>
   1.672 +     *
   1.673 +     * @param  out
   1.674 +     *         The output byte buffer
   1.675 +     *
   1.676 +     * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
   1.677 +     *          {@link CoderResult#OVERFLOW}
   1.678 +     */
   1.679 +    protected CoderResult implFlush(ByteBuffer out) {
   1.680 +        return CoderResult.UNDERFLOW;
   1.681 +    }
   1.682 +
   1.683 +    /**
   1.684 +     * Resets this encoder, clearing any internal state.
   1.685 +     *
   1.686 +     * <p> This method resets charset-independent state and also invokes the
   1.687 +     * {@link #implReset() implReset} method in order to perform any
   1.688 +     * charset-specific reset actions.  </p>
   1.689 +     *
   1.690 +     * @return  This encoder
   1.691 +     *
   1.692 +     */
   1.693 +    public final CharsetEncoder reset() {
   1.694 +        implReset();
   1.695 +        state = ST_RESET;
   1.696 +        return this;
   1.697 +    }
   1.698 +
   1.699 +    /**
   1.700 +     * Resets this encoder, clearing any charset-specific internal state.
   1.701 +     *
   1.702 +     * <p> The default implementation of this method does nothing.  This method
   1.703 +     * should be overridden by encoders that maintain internal state.  </p>
   1.704 +     */
   1.705 +    protected void implReset() { }
   1.706 +
   1.707 +    /**
   1.708 +     * Encodes one or more characters into one or more bytes.
   1.709 +     *
   1.710 +     * <p> This method encapsulates the basic encoding loop, encoding as many
   1.711 +     * characters as possible until it either runs out of input, runs out of room
   1.712 +     * in the output buffer, or encounters an encoding error.  This method is
   1.713 +     * invoked by the {@link #encode encode} method, which handles result
   1.714 +     * interpretation and error recovery.
   1.715 +     *
   1.716 +     * <p> The buffers are read from, and written to, starting at their current
   1.717 +     * positions.  At most {@link Buffer#remaining in.remaining()} characters
   1.718 +     * will be read, and at most {@link Buffer#remaining out.remaining()}
   1.719 +     * bytes will be written.  The buffers' positions will be advanced to
   1.720 +     * reflect the characters read and the bytes written, but their marks and
   1.721 +     * limits will not be modified.
   1.722 +     *
   1.723 +     * <p> This method returns a {@link CoderResult} object to describe its
   1.724 +     * reason for termination, in the same manner as the {@link #encode encode}
   1.725 +     * method.  Most implementations of this method will handle encoding errors
   1.726 +     * by returning an appropriate result object for interpretation by the
   1.727 +     * {@link #encode encode} method.  An optimized implementation may instead
   1.728 +     * examine the relevant error action and implement that action itself.
   1.729 +     *
   1.730 +     * <p> An implementation of this method may perform arbitrary lookahead by
   1.731 +     * returning {@link CoderResult#UNDERFLOW} until it receives sufficient
   1.732 +     * input.  </p>
   1.733 +     *
   1.734 +     * @param  in
   1.735 +     *         The input character buffer
   1.736 +     *
   1.737 +     * @param  out
   1.738 +     *         The output byte buffer
   1.739 +     *
   1.740 +     * @return  A coder-result object describing the reason for termination
   1.741 +     */
   1.742 +    protected abstract CoderResult encodeLoop(CharBuffer in,
   1.743 +                                              ByteBuffer out);
   1.744 +
   1.745 +    /**
   1.746 +     * Convenience method that encodes the remaining content of a single input
   1.747 +     * character buffer into a newly-allocated byte buffer.
   1.748 +     *
   1.749 +     * <p> This method implements an entire <a href="#steps">encoding
   1.750 +     * operation</a>; that is, it resets this encoder, then it encodes the
   1.751 +     * characters in the given character buffer, and finally it flushes this
   1.752 +     * encoder.  This method should therefore not be invoked if an encoding
   1.753 +     * operation is already in progress.  </p>
   1.754 +     *
   1.755 +     * @param  in
   1.756 +     *         The input character buffer
   1.757 +     *
   1.758 +     * @return A newly-allocated byte buffer containing the result of the
   1.759 +     *         encoding operation.  The buffer's position will be zero and its
   1.760 +     *         limit will follow the last byte written.
   1.761 +     *
   1.762 +     * @throws  IllegalStateException
   1.763 +     *          If an encoding operation is already in progress
   1.764 +     *
   1.765 +     * @throws  MalformedInputException
   1.766 +     *          If the character sequence starting at the input buffer's current
   1.767 +     *          position is not a legal sixteen-bit Unicode sequence and the current malformed-input action
   1.768 +     *          is {@link CodingErrorAction#REPORT}
   1.769 +     *
   1.770 +     * @throws  UnmappableCharacterException
   1.771 +     *          If the character sequence starting at the input buffer's current
   1.772 +     *          position cannot be mapped to an equivalent byte sequence and
   1.773 +     *          the current unmappable-character action is {@link
   1.774 +     *          CodingErrorAction#REPORT}
   1.775 +     */
   1.776 +    public final ByteBuffer encode(CharBuffer in)
   1.777 +        throws CharacterCodingException
   1.778 +    {
   1.779 +        int n = (int)(in.remaining() * averageBytesPerChar());
   1.780 +        ByteBuffer out = ByteBuffer.allocate(n);
   1.781 +
   1.782 +        if ((n == 0) && (in.remaining() == 0))
   1.783 +            return out;
   1.784 +        reset();
   1.785 +        for (;;) {
   1.786 +            CoderResult cr = in.hasRemaining() ?
   1.787 +                encode(in, out, true) : CoderResult.UNDERFLOW;
   1.788 +            if (cr.isUnderflow())
   1.789 +                cr = flush(out);
   1.790 +
   1.791 +            if (cr.isUnderflow())
   1.792 +                break;
   1.793 +            if (cr.isOverflow()) {
   1.794 +                n = 2*n + 1;    // Ensure progress; n might be 0!
   1.795 +                ByteBuffer o = ByteBuffer.allocate(n);
   1.796 +                out.flip();
   1.797 +                o.put(out);
   1.798 +                out = o;
   1.799 +                continue;
   1.800 +            }
   1.801 +            cr.throwException();
   1.802 +        }
   1.803 +        out.flip();
   1.804 +        return out;
   1.805 +    }
   1.806 +
   1.807 +
   1.808 +
   1.809 +
   1.810 +
   1.811 +
   1.812 +
   1.813 +
   1.814 +
   1.815 +
   1.816 +
   1.817 +
   1.818 +
   1.819 +
   1.820 +
   1.821 +
   1.822 +
   1.823 +
   1.824 +
   1.825 +
   1.826 +
   1.827 +
   1.828 +
   1.829 +
   1.830 +
   1.831 +
   1.832 +
   1.833 +
   1.834 +
   1.835 +
   1.836 +
   1.837 +
   1.838 +
   1.839 +
   1.840 +
   1.841 +
   1.842 +
   1.843 +
   1.844 +
   1.845 +
   1.846 +
   1.847 +
   1.848 +
   1.849 +
   1.850 +
   1.851 +
   1.852 +
   1.853 +
   1.854 +
   1.855 +
   1.856 +
   1.857 +
   1.858 +
   1.859 +
   1.860 +
   1.861 +
   1.862 +
   1.863 +
   1.864 +
   1.865 +
   1.866 +
   1.867 +
   1.868 +
   1.869 +
   1.870 +
   1.871 +
   1.872 +
   1.873 +
   1.874 +
   1.875 +
   1.876 +
   1.877 +
   1.878 +
   1.879 +
   1.880 +
   1.881 +
   1.882 +
   1.883 +
   1.884 +
   1.885 +    private boolean canEncode(CharBuffer cb) {
   1.886 +        if (state == ST_FLUSHED)
   1.887 +            reset();
   1.888 +        else if (state != ST_RESET)
   1.889 +            throwIllegalStateException(state, ST_CODING);
   1.890 +        CodingErrorAction ma = malformedInputAction();
   1.891 +        CodingErrorAction ua = unmappableCharacterAction();
   1.892 +        try {
   1.893 +            onMalformedInput(CodingErrorAction.REPORT);
   1.894 +            onUnmappableCharacter(CodingErrorAction.REPORT);
   1.895 +            encode(cb);
   1.896 +        } catch (CharacterCodingException x) {
   1.897 +            return false;
   1.898 +        } finally {
   1.899 +            onMalformedInput(ma);
   1.900 +            onUnmappableCharacter(ua);
   1.901 +            reset();
   1.902 +        }
   1.903 +        return true;
   1.904 +    }
   1.905 +
   1.906 +    /**
   1.907 +     * Tells whether or not this encoder can encode the given character.
   1.908 +     *
   1.909 +     * <p> This method returns <tt>false</tt> if the given character is a
   1.910 +     * surrogate character; such characters can be interpreted only when they
   1.911 +     * are members of a pair consisting of a high surrogate followed by a low
   1.912 +     * surrogate.  The {@link #canEncode(java.lang.CharSequence)
   1.913 +     * canEncode(CharSequence)} method may be used to test whether or not a
   1.914 +     * character sequence can be encoded.
   1.915 +     *
   1.916 +     * <p> This method may modify this encoder's state; it should therefore not
   1.917 +     * be invoked if an <a href="#steps">encoding operation</a> is already in
   1.918 +     * progress.
   1.919 +     *
   1.920 +     * <p> The default implementation of this method is not very efficient; it
   1.921 +     * should generally be overridden to improve performance.  </p>
   1.922 +     *
   1.923 +     * @return  <tt>true</tt> if, and only if, this encoder can encode
   1.924 +     *          the given character
   1.925 +     *
   1.926 +     * @throws  IllegalStateException
   1.927 +     *          If an encoding operation is already in progress
   1.928 +     */
   1.929 +    public boolean canEncode(char c) {
   1.930 +        CharBuffer cb = CharBuffer.allocate(1);
   1.931 +        cb.put(c);
   1.932 +        cb.flip();
   1.933 +        return canEncode(cb);
   1.934 +    }
   1.935 +
   1.936 +    /**
   1.937 +     * Tells whether or not this encoder can encode the given character
   1.938 +     * sequence.
   1.939 +     *
   1.940 +     * <p> If this method returns <tt>false</tt> for a particular character
   1.941 +     * sequence then more information about why the sequence cannot be encoded
   1.942 +     * may be obtained by performing a full <a href="#steps">encoding
   1.943 +     * operation</a>.
   1.944 +     *
   1.945 +     * <p> This method may modify this encoder's state; it should therefore not
   1.946 +     * be invoked if an encoding operation is already in progress.
   1.947 +     *
   1.948 +     * <p> The default implementation of this method is not very efficient; it
   1.949 +     * should generally be overridden to improve performance.  </p>
   1.950 +     *
   1.951 +     * @return  <tt>true</tt> if, and only if, this encoder can encode
   1.952 +     *          the given character without throwing any exceptions and without
   1.953 +     *          performing any replacements
   1.954 +     *
   1.955 +     * @throws  IllegalStateException
   1.956 +     *          If an encoding operation is already in progress
   1.957 +     */
   1.958 +    public boolean canEncode(CharSequence cs) {
   1.959 +        CharBuffer cb;
   1.960 +        if (cs instanceof CharBuffer)
   1.961 +            cb = ((CharBuffer)cs).duplicate();
   1.962 +        else
   1.963 +            cb = CharBuffer.wrap(cs.toString());
   1.964 +        return canEncode(cb);
   1.965 +    }
   1.966 +
   1.967 +
   1.968 +
   1.969 +
   1.970 +    private void throwIllegalStateException(int from, int to) {
   1.971 +        throw new IllegalStateException("Current state = " + stateNames[from]
   1.972 +                                        + ", new state = " + stateNames[to]);
   1.973 +    }
   1.974 +
   1.975 +}