emul/src/main/java/java/lang/reflect/Field.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Tue, 04 Dec 2012 14:08:19 +0100
branchreflection
changeset 259 9b0fbf4ec230
child 260 1d03cb35fbda
permissions -rw-r--r--
Merging in some reflection classes from jdk7-b147
     1 /*
     2  * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.  Oracle designates this
     8  * particular file as subject to the "Classpath" exception as provided
     9  * by Oracle in the LICENSE file that accompanied this code.
    10  *
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    14  * version 2 for more details (a copy is included in the LICENSE file that
    15  * accompanied this code).
    16  *
    17  * You should have received a copy of the GNU General Public License version
    18  * 2 along with this work; if not, write to the Free Software Foundation,
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    20  *
    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    22  * or visit www.oracle.com if you need additional information or have any
    23  * questions.
    24  */
    25 
    26 package java.lang.reflect;
    27 
    28 import sun.reflect.FieldAccessor;
    29 import sun.reflect.Reflection;
    30 import sun.reflect.generics.repository.FieldRepository;
    31 import sun.reflect.generics.factory.CoreReflectionFactory;
    32 import sun.reflect.generics.factory.GenericsFactory;
    33 import sun.reflect.generics.scope.ClassScope;
    34 import java.lang.annotation.Annotation;
    35 import java.util.Map;
    36 import sun.reflect.annotation.AnnotationParser;
    37 
    38 
    39 /**
    40  * A {@code Field} provides information about, and dynamic access to, a
    41  * single field of a class or an interface.  The reflected field may
    42  * be a class (static) field or an instance field.
    43  *
    44  * <p>A {@code Field} permits widening conversions to occur during a get or
    45  * set access operation, but throws an {@code IllegalArgumentException} if a
    46  * narrowing conversion would occur.
    47  *
    48  * @see Member
    49  * @see java.lang.Class
    50  * @see java.lang.Class#getFields()
    51  * @see java.lang.Class#getField(String)
    52  * @see java.lang.Class#getDeclaredFields()
    53  * @see java.lang.Class#getDeclaredField(String)
    54  *
    55  * @author Kenneth Russell
    56  * @author Nakul Saraiya
    57  */
    58 public final
    59 class Field extends AccessibleObject implements Member {
    60 
    61     private Class<?>            clazz;
    62     private int                 slot;
    63     // This is guaranteed to be interned by the VM in the 1.4
    64     // reflection implementation
    65     private String              name;
    66     private Class<?>            type;
    67     private int                 modifiers;
    68     // Generics and annotations support
    69     private transient String    signature;
    70     // generic info repository; lazily initialized
    71     private transient FieldRepository genericInfo;
    72     private byte[]              annotations;
    73     // Cached field accessor created without override
    74     private FieldAccessor fieldAccessor;
    75     // Cached field accessor created with override
    76     private FieldAccessor overrideFieldAccessor;
    77     // For sharing of FieldAccessors. This branching structure is
    78     // currently only two levels deep (i.e., one root Field and
    79     // potentially many Field objects pointing to it.)
    80     private Field               root;
    81 
    82     // Generics infrastructure
    83 
    84     private String getGenericSignature() {return signature;}
    85 
    86     // Accessor for factory
    87     private GenericsFactory getFactory() {
    88         Class<?> c = getDeclaringClass();
    89         // create scope and factory
    90         return CoreReflectionFactory.make(c, ClassScope.make(c));
    91     }
    92 
    93     // Accessor for generic info repository
    94     private FieldRepository getGenericInfo() {
    95         // lazily initialize repository if necessary
    96         if (genericInfo == null) {
    97             // create and cache generic info repository
    98             genericInfo = FieldRepository.make(getGenericSignature(),
    99                                                getFactory());
   100         }
   101         return genericInfo; //return cached repository
   102     }
   103 
   104 
   105     /**
   106      * Package-private constructor used by ReflectAccess to enable
   107      * instantiation of these objects in Java code from the java.lang
   108      * package via sun.reflect.LangReflectAccess.
   109      */
   110     Field(Class<?> declaringClass,
   111           String name,
   112           Class<?> type,
   113           int modifiers,
   114           int slot,
   115           String signature,
   116           byte[] annotations)
   117     {
   118         this.clazz = declaringClass;
   119         this.name = name;
   120         this.type = type;
   121         this.modifiers = modifiers;
   122         this.slot = slot;
   123         this.signature = signature;
   124         this.annotations = annotations;
   125     }
   126 
   127     /**
   128      * Package-private routine (exposed to java.lang.Class via
   129      * ReflectAccess) which returns a copy of this Field. The copy's
   130      * "root" field points to this Field.
   131      */
   132     Field copy() {
   133         // This routine enables sharing of FieldAccessor objects
   134         // among Field objects which refer to the same underlying
   135         // method in the VM. (All of this contortion is only necessary
   136         // because of the "accessibility" bit in AccessibleObject,
   137         // which implicitly requires that new java.lang.reflect
   138         // objects be fabricated for each reflective call on Class
   139         // objects.)
   140         Field res = new Field(clazz, name, type, modifiers, slot, signature, annotations);
   141         res.root = this;
   142         // Might as well eagerly propagate this if already present
   143         res.fieldAccessor = fieldAccessor;
   144         res.overrideFieldAccessor = overrideFieldAccessor;
   145         return res;
   146     }
   147 
   148     /**
   149      * Returns the {@code Class} object representing the class or interface
   150      * that declares the field represented by this {@code Field} object.
   151      */
   152     public Class<?> getDeclaringClass() {
   153         return clazz;
   154     }
   155 
   156     /**
   157      * Returns the name of the field represented by this {@code Field} object.
   158      */
   159     public String getName() {
   160         return name;
   161     }
   162 
   163     /**
   164      * Returns the Java language modifiers for the field represented
   165      * by this {@code Field} object, as an integer. The {@code Modifier} class should
   166      * be used to decode the modifiers.
   167      *
   168      * @see Modifier
   169      */
   170     public int getModifiers() {
   171         return modifiers;
   172     }
   173 
   174     /**
   175      * Returns {@code true} if this field represents an element of
   176      * an enumerated type; returns {@code false} otherwise.
   177      *
   178      * @return {@code true} if and only if this field represents an element of
   179      * an enumerated type.
   180      * @since 1.5
   181      */
   182     public boolean isEnumConstant() {
   183         return (getModifiers() & Modifier.ENUM) != 0;
   184     }
   185 
   186     /**
   187      * Returns {@code true} if this field is a synthetic
   188      * field; returns {@code false} otherwise.
   189      *
   190      * @return true if and only if this field is a synthetic
   191      * field as defined by the Java Language Specification.
   192      * @since 1.5
   193      */
   194     public boolean isSynthetic() {
   195         return Modifier.isSynthetic(getModifiers());
   196     }
   197 
   198     /**
   199      * Returns a {@code Class} object that identifies the
   200      * declared type for the field represented by this
   201      * {@code Field} object.
   202      *
   203      * @return a {@code Class} object identifying the declared
   204      * type of the field represented by this object
   205      */
   206     public Class<?> getType() {
   207         return type;
   208     }
   209 
   210     /**
   211      * Returns a {@code Type} object that represents the declared type for
   212      * the field represented by this {@code Field} object.
   213      *
   214      * <p>If the {@code Type} is a parameterized type, the
   215      * {@code Type} object returned must accurately reflect the
   216      * actual type parameters used in the source code.
   217      *
   218      * <p>If the type of the underlying field is a type variable or a
   219      * parameterized type, it is created. Otherwise, it is resolved.
   220      *
   221      * @return a {@code Type} object that represents the declared type for
   222      *     the field represented by this {@code Field} object
   223      * @throws GenericSignatureFormatError if the generic field
   224      *     signature does not conform to the format specified in
   225      *     <cite>The Java&trade; Virtual Machine Specification</cite>
   226      * @throws TypeNotPresentException if the generic type
   227      *     signature of the underlying field refers to a non-existent
   228      *     type declaration
   229      * @throws MalformedParameterizedTypeException if the generic
   230      *     signature of the underlying field refers to a parameterized type
   231      *     that cannot be instantiated for any reason
   232      * @since 1.5
   233      */
   234     public Type getGenericType() {
   235         if (getGenericSignature() != null)
   236             return getGenericInfo().getGenericType();
   237         else
   238             return getType();
   239     }
   240 
   241 
   242     /**
   243      * Compares this {@code Field} against the specified object.  Returns
   244      * true if the objects are the same.  Two {@code Field} objects are the same if
   245      * they were declared by the same class and have the same name
   246      * and type.
   247      */
   248     public boolean equals(Object obj) {
   249         if (obj != null && obj instanceof Field) {
   250             Field other = (Field)obj;
   251             return (getDeclaringClass() == other.getDeclaringClass())
   252                 && (getName() == other.getName())
   253                 && (getType() == other.getType());
   254         }
   255         return false;
   256     }
   257 
   258     /**
   259      * Returns a hashcode for this {@code Field}.  This is computed as the
   260      * exclusive-or of the hashcodes for the underlying field's
   261      * declaring class name and its name.
   262      */
   263     public int hashCode() {
   264         return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
   265     }
   266 
   267     /**
   268      * Returns a string describing this {@code Field}.  The format is
   269      * the access modifiers for the field, if any, followed
   270      * by the field type, followed by a space, followed by
   271      * the fully-qualified name of the class declaring the field,
   272      * followed by a period, followed by the name of the field.
   273      * For example:
   274      * <pre>
   275      *    public static final int java.lang.Thread.MIN_PRIORITY
   276      *    private int java.io.FileDescriptor.fd
   277      * </pre>
   278      *
   279      * <p>The modifiers are placed in canonical order as specified by
   280      * "The Java Language Specification".  This is {@code public},
   281      * {@code protected} or {@code private} first, and then other
   282      * modifiers in the following order: {@code static}, {@code final},
   283      * {@code transient}, {@code volatile}.
   284      */
   285     public String toString() {
   286         int mod = getModifiers();
   287         return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
   288             + getTypeName(getType()) + " "
   289             + getTypeName(getDeclaringClass()) + "."
   290             + getName());
   291     }
   292 
   293     /**
   294      * Returns a string describing this {@code Field}, including
   295      * its generic type.  The format is the access modifiers for the
   296      * field, if any, followed by the generic field type, followed by
   297      * a space, followed by the fully-qualified name of the class
   298      * declaring the field, followed by a period, followed by the name
   299      * of the field.
   300      *
   301      * <p>The modifiers are placed in canonical order as specified by
   302      * "The Java Language Specification".  This is {@code public},
   303      * {@code protected} or {@code private} first, and then other
   304      * modifiers in the following order: {@code static}, {@code final},
   305      * {@code transient}, {@code volatile}.
   306      *
   307      * @return a string describing this {@code Field}, including
   308      * its generic type
   309      *
   310      * @since 1.5
   311      */
   312     public String toGenericString() {
   313         int mod = getModifiers();
   314         Type fieldType = getGenericType();
   315         return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
   316             +  ((fieldType instanceof Class) ?
   317                 getTypeName((Class)fieldType): fieldType.toString())+ " "
   318             + getTypeName(getDeclaringClass()) + "."
   319             + getName());
   320     }
   321 
   322     /**
   323      * Returns the value of the field represented by this {@code Field}, on
   324      * the specified object. The value is automatically wrapped in an
   325      * object if it has a primitive type.
   326      *
   327      * <p>The underlying field's value is obtained as follows:
   328      *
   329      * <p>If the underlying field is a static field, the {@code obj} argument
   330      * is ignored; it may be null.
   331      *
   332      * <p>Otherwise, the underlying field is an instance field.  If the
   333      * specified {@code obj} argument is null, the method throws a
   334      * {@code NullPointerException}. If the specified object is not an
   335      * instance of the class or interface declaring the underlying
   336      * field, the method throws an {@code IllegalArgumentException}.
   337      *
   338      * <p>If this {@code Field} object is enforcing Java language access control, and
   339      * the underlying field is inaccessible, the method throws an
   340      * {@code IllegalAccessException}.
   341      * If the underlying field is static, the class that declared the
   342      * field is initialized if it has not already been initialized.
   343      *
   344      * <p>Otherwise, the value is retrieved from the underlying instance
   345      * or static field.  If the field has a primitive type, the value
   346      * is wrapped in an object before being returned, otherwise it is
   347      * returned as is.
   348      *
   349      * <p>If the field is hidden in the type of {@code obj},
   350      * the field's value is obtained according to the preceding rules.
   351      *
   352      * @param obj object from which the represented field's value is
   353      * to be extracted
   354      * @return the value of the represented field in object
   355      * {@code obj}; primitive values are wrapped in an appropriate
   356      * object before being returned
   357      *
   358      * @exception IllegalAccessException    if this {@code Field} object
   359      *              is enforcing Java language access control and the underlying
   360      *              field is inaccessible.
   361      * @exception IllegalArgumentException  if the specified object is not an
   362      *              instance of the class or interface declaring the underlying
   363      *              field (or a subclass or implementor thereof).
   364      * @exception NullPointerException      if the specified object is null
   365      *              and the field is an instance field.
   366      * @exception ExceptionInInitializerError if the initialization provoked
   367      *              by this method fails.
   368      */
   369     public Object get(Object obj)
   370         throws IllegalArgumentException, IllegalAccessException
   371     {
   372         return getFieldAccessor(obj).get(obj);
   373     }
   374 
   375     /**
   376      * Gets the value of a static or instance {@code boolean} field.
   377      *
   378      * @param obj the object to extract the {@code boolean} value
   379      * from
   380      * @return the value of the {@code boolean} field
   381      *
   382      * @exception IllegalAccessException    if this {@code Field} object
   383      *              is enforcing Java language access control and the underlying
   384      *              field is inaccessible.
   385      * @exception IllegalArgumentException  if the specified object is not
   386      *              an instance of the class or interface declaring the
   387      *              underlying field (or a subclass or implementor
   388      *              thereof), or if the field value cannot be
   389      *              converted to the type {@code boolean} by a
   390      *              widening conversion.
   391      * @exception NullPointerException      if the specified object is null
   392      *              and the field is an instance field.
   393      * @exception ExceptionInInitializerError if the initialization provoked
   394      *              by this method fails.
   395      * @see       Field#get
   396      */
   397     public boolean getBoolean(Object obj)
   398         throws IllegalArgumentException, IllegalAccessException
   399     {
   400         return getFieldAccessor(obj).getBoolean(obj);
   401     }
   402 
   403     /**
   404      * Gets the value of a static or instance {@code byte} field.
   405      *
   406      * @param obj the object to extract the {@code byte} value
   407      * from
   408      * @return the value of the {@code byte} field
   409      *
   410      * @exception IllegalAccessException    if this {@code Field} object
   411      *              is enforcing Java language access control and the underlying
   412      *              field is inaccessible.
   413      * @exception IllegalArgumentException  if the specified object is not
   414      *              an instance of the class or interface declaring the
   415      *              underlying field (or a subclass or implementor
   416      *              thereof), or if the field value cannot be
   417      *              converted to the type {@code byte} by a
   418      *              widening conversion.
   419      * @exception NullPointerException      if the specified object is null
   420      *              and the field is an instance field.
   421      * @exception ExceptionInInitializerError if the initialization provoked
   422      *              by this method fails.
   423      * @see       Field#get
   424      */
   425     public byte getByte(Object obj)
   426         throws IllegalArgumentException, IllegalAccessException
   427     {
   428         return getFieldAccessor(obj).getByte(obj);
   429     }
   430 
   431     /**
   432      * Gets the value of a static or instance field of type
   433      * {@code char} or of another primitive type convertible to
   434      * type {@code char} via a widening conversion.
   435      *
   436      * @param obj the object to extract the {@code char} value
   437      * from
   438      * @return the value of the field converted to type {@code char}
   439      *
   440      * @exception IllegalAccessException    if this {@code Field} object
   441      *              is enforcing Java language access control and the underlying
   442      *              field is inaccessible.
   443      * @exception IllegalArgumentException  if the specified object is not
   444      *              an instance of the class or interface declaring the
   445      *              underlying field (or a subclass or implementor
   446      *              thereof), or if the field value cannot be
   447      *              converted to the type {@code char} by a
   448      *              widening conversion.
   449      * @exception NullPointerException      if the specified object is null
   450      *              and the field is an instance field.
   451      * @exception ExceptionInInitializerError if the initialization provoked
   452      *              by this method fails.
   453      * @see Field#get
   454      */
   455     public char getChar(Object obj)
   456         throws IllegalArgumentException, IllegalAccessException
   457     {
   458         return getFieldAccessor(obj).getChar(obj);
   459     }
   460 
   461     /**
   462      * Gets the value of a static or instance field of type
   463      * {@code short} or of another primitive type convertible to
   464      * type {@code short} via a widening conversion.
   465      *
   466      * @param obj the object to extract the {@code short} value
   467      * from
   468      * @return the value of the field converted to type {@code short}
   469      *
   470      * @exception IllegalAccessException    if this {@code Field} object
   471      *              is enforcing Java language access control and the underlying
   472      *              field is inaccessible.
   473      * @exception IllegalArgumentException  if the specified object is not
   474      *              an instance of the class or interface declaring the
   475      *              underlying field (or a subclass or implementor
   476      *              thereof), or if the field value cannot be
   477      *              converted to the type {@code short} by a
   478      *              widening conversion.
   479      * @exception NullPointerException      if the specified object is null
   480      *              and the field is an instance field.
   481      * @exception ExceptionInInitializerError if the initialization provoked
   482      *              by this method fails.
   483      * @see       Field#get
   484      */
   485     public short getShort(Object obj)
   486         throws IllegalArgumentException, IllegalAccessException
   487     {
   488         return getFieldAccessor(obj).getShort(obj);
   489     }
   490 
   491     /**
   492      * Gets the value of a static or instance field of type
   493      * {@code int} or of another primitive type convertible to
   494      * type {@code int} via a widening conversion.
   495      *
   496      * @param obj the object to extract the {@code int} value
   497      * from
   498      * @return the value of the field converted to type {@code int}
   499      *
   500      * @exception IllegalAccessException    if this {@code Field} object
   501      *              is enforcing Java language access control and the underlying
   502      *              field is inaccessible.
   503      * @exception IllegalArgumentException  if the specified object is not
   504      *              an instance of the class or interface declaring the
   505      *              underlying field (or a subclass or implementor
   506      *              thereof), or if the field value cannot be
   507      *              converted to the type {@code int} by a
   508      *              widening conversion.
   509      * @exception NullPointerException      if the specified object is null
   510      *              and the field is an instance field.
   511      * @exception ExceptionInInitializerError if the initialization provoked
   512      *              by this method fails.
   513      * @see       Field#get
   514      */
   515     public int getInt(Object obj)
   516         throws IllegalArgumentException, IllegalAccessException
   517     {
   518         return getFieldAccessor(obj).getInt(obj);
   519     }
   520 
   521     /**
   522      * Gets the value of a static or instance field of type
   523      * {@code long} or of another primitive type convertible to
   524      * type {@code long} via a widening conversion.
   525      *
   526      * @param obj the object to extract the {@code long} value
   527      * from
   528      * @return the value of the field converted to type {@code long}
   529      *
   530      * @exception IllegalAccessException    if this {@code Field} object
   531      *              is enforcing Java language access control and the underlying
   532      *              field is inaccessible.
   533      * @exception IllegalArgumentException  if the specified object is not
   534      *              an instance of the class or interface declaring the
   535      *              underlying field (or a subclass or implementor
   536      *              thereof), or if the field value cannot be
   537      *              converted to the type {@code long} by a
   538      *              widening conversion.
   539      * @exception NullPointerException      if the specified object is null
   540      *              and the field is an instance field.
   541      * @exception ExceptionInInitializerError if the initialization provoked
   542      *              by this method fails.
   543      * @see       Field#get
   544      */
   545     public long getLong(Object obj)
   546         throws IllegalArgumentException, IllegalAccessException
   547     {
   548         return getFieldAccessor(obj).getLong(obj);
   549     }
   550 
   551     /**
   552      * Gets the value of a static or instance field of type
   553      * {@code float} or of another primitive type convertible to
   554      * type {@code float} via a widening conversion.
   555      *
   556      * @param obj the object to extract the {@code float} value
   557      * from
   558      * @return the value of the field converted to type {@code float}
   559      *
   560      * @exception IllegalAccessException    if this {@code Field} object
   561      *              is enforcing Java language access control and the underlying
   562      *              field is inaccessible.
   563      * @exception IllegalArgumentException  if the specified object is not
   564      *              an instance of the class or interface declaring the
   565      *              underlying field (or a subclass or implementor
   566      *              thereof), or if the field value cannot be
   567      *              converted to the type {@code float} by a
   568      *              widening conversion.
   569      * @exception NullPointerException      if the specified object is null
   570      *              and the field is an instance field.
   571      * @exception ExceptionInInitializerError if the initialization provoked
   572      *              by this method fails.
   573      * @see Field#get
   574      */
   575     public float getFloat(Object obj)
   576         throws IllegalArgumentException, IllegalAccessException
   577     {
   578         return getFieldAccessor(obj).getFloat(obj);
   579     }
   580 
   581     /**
   582      * Gets the value of a static or instance field of type
   583      * {@code double} or of another primitive type convertible to
   584      * type {@code double} via a widening conversion.
   585      *
   586      * @param obj the object to extract the {@code double} value
   587      * from
   588      * @return the value of the field converted to type {@code double}
   589      *
   590      * @exception IllegalAccessException    if this {@code Field} object
   591      *              is enforcing Java language access control and the underlying
   592      *              field is inaccessible.
   593      * @exception IllegalArgumentException  if the specified object is not
   594      *              an instance of the class or interface declaring the
   595      *              underlying field (or a subclass or implementor
   596      *              thereof), or if the field value cannot be
   597      *              converted to the type {@code double} by a
   598      *              widening conversion.
   599      * @exception NullPointerException      if the specified object is null
   600      *              and the field is an instance field.
   601      * @exception ExceptionInInitializerError if the initialization provoked
   602      *              by this method fails.
   603      * @see       Field#get
   604      */
   605     public double getDouble(Object obj)
   606         throws IllegalArgumentException, IllegalAccessException
   607     {
   608         return getFieldAccessor(obj).getDouble(obj);
   609     }
   610 
   611     /**
   612      * Sets the field represented by this {@code Field} object on the
   613      * specified object argument to the specified new value. The new
   614      * value is automatically unwrapped if the underlying field has a
   615      * primitive type.
   616      *
   617      * <p>The operation proceeds as follows:
   618      *
   619      * <p>If the underlying field is static, the {@code obj} argument is
   620      * ignored; it may be null.
   621      *
   622      * <p>Otherwise the underlying field is an instance field.  If the
   623      * specified object argument is null, the method throws a
   624      * {@code NullPointerException}.  If the specified object argument is not
   625      * an instance of the class or interface declaring the underlying
   626      * field, the method throws an {@code IllegalArgumentException}.
   627      *
   628      * <p>If this {@code Field} object is enforcing Java language access control, and
   629      * the underlying field is inaccessible, the method throws an
   630      * {@code IllegalAccessException}.
   631      *
   632      * <p>If the underlying field is final, the method throws an
   633      * {@code IllegalAccessException} unless {@code setAccessible(true)}
   634      * has succeeded for this {@code Field} object
   635      * and the field is non-static. Setting a final field in this way
   636      * is meaningful only during deserialization or reconstruction of
   637      * instances of classes with blank final fields, before they are
   638      * made available for access by other parts of a program. Use in
   639      * any other context may have unpredictable effects, including cases
   640      * in which other parts of a program continue to use the original
   641      * value of this field.
   642      *
   643      * <p>If the underlying field is of a primitive type, an unwrapping
   644      * conversion is attempted to convert the new value to a value of
   645      * a primitive type.  If this attempt fails, the method throws an
   646      * {@code IllegalArgumentException}.
   647      *
   648      * <p>If, after possible unwrapping, the new value cannot be
   649      * converted to the type of the underlying field by an identity or
   650      * widening conversion, the method throws an
   651      * {@code IllegalArgumentException}.
   652      *
   653      * <p>If the underlying field is static, the class that declared the
   654      * field is initialized if it has not already been initialized.
   655      *
   656      * <p>The field is set to the possibly unwrapped and widened new value.
   657      *
   658      * <p>If the field is hidden in the type of {@code obj},
   659      * the field's value is set according to the preceding rules.
   660      *
   661      * @param obj the object whose field should be modified
   662      * @param value the new value for the field of {@code obj}
   663      * being modified
   664      *
   665      * @exception IllegalAccessException    if this {@code Field} object
   666      *              is enforcing Java language access control and the underlying
   667      *              field is either inaccessible or final.
   668      * @exception IllegalArgumentException  if the specified object is not an
   669      *              instance of the class or interface declaring the underlying
   670      *              field (or a subclass or implementor thereof),
   671      *              or if an unwrapping conversion fails.
   672      * @exception NullPointerException      if the specified object is null
   673      *              and the field is an instance field.
   674      * @exception ExceptionInInitializerError if the initialization provoked
   675      *              by this method fails.
   676      */
   677     public void set(Object obj, Object value)
   678         throws IllegalArgumentException, IllegalAccessException
   679     {
   680         getFieldAccessor(obj).set(obj, value);
   681     }
   682 
   683     /**
   684      * Sets the value of a field as a {@code boolean} on the specified object.
   685      * This method is equivalent to
   686      * {@code set(obj, zObj)},
   687      * where {@code zObj} is a {@code Boolean} object and
   688      * {@code zObj.booleanValue() == z}.
   689      *
   690      * @param obj the object whose field should be modified
   691      * @param z   the new value for the field of {@code obj}
   692      * being modified
   693      *
   694      * @exception IllegalAccessException    if this {@code Field} object
   695      *              is enforcing Java language access control and the underlying
   696      *              field is either inaccessible or final.
   697      * @exception IllegalArgumentException  if the specified object is not an
   698      *              instance of the class or interface declaring the underlying
   699      *              field (or a subclass or implementor thereof),
   700      *              or if an unwrapping conversion fails.
   701      * @exception NullPointerException      if the specified object is null
   702      *              and the field is an instance field.
   703      * @exception ExceptionInInitializerError if the initialization provoked
   704      *              by this method fails.
   705      * @see       Field#set
   706      */
   707     public void setBoolean(Object obj, boolean z)
   708         throws IllegalArgumentException, IllegalAccessException
   709     {
   710         getFieldAccessor(obj).setBoolean(obj, z);
   711     }
   712 
   713     /**
   714      * Sets the value of a field as a {@code byte} on the specified object.
   715      * This method is equivalent to
   716      * {@code set(obj, bObj)},
   717      * where {@code bObj} is a {@code Byte} object and
   718      * {@code bObj.byteValue() == b}.
   719      *
   720      * @param obj the object whose field should be modified
   721      * @param b   the new value for the field of {@code obj}
   722      * being modified
   723      *
   724      * @exception IllegalAccessException    if this {@code Field} object
   725      *              is enforcing Java language access control and the underlying
   726      *              field is either inaccessible or final.
   727      * @exception IllegalArgumentException  if the specified object is not an
   728      *              instance of the class or interface declaring the underlying
   729      *              field (or a subclass or implementor thereof),
   730      *              or if an unwrapping conversion fails.
   731      * @exception NullPointerException      if the specified object is null
   732      *              and the field is an instance field.
   733      * @exception ExceptionInInitializerError if the initialization provoked
   734      *              by this method fails.
   735      * @see       Field#set
   736      */
   737     public void setByte(Object obj, byte b)
   738         throws IllegalArgumentException, IllegalAccessException
   739     {
   740         getFieldAccessor(obj).setByte(obj, b);
   741     }
   742 
   743     /**
   744      * Sets the value of a field as a {@code char} on the specified object.
   745      * This method is equivalent to
   746      * {@code set(obj, cObj)},
   747      * where {@code cObj} is a {@code Character} object and
   748      * {@code cObj.charValue() == c}.
   749      *
   750      * @param obj the object whose field should be modified
   751      * @param c   the new value for the field of {@code obj}
   752      * being modified
   753      *
   754      * @exception IllegalAccessException    if this {@code Field} object
   755      *              is enforcing Java language access control and the underlying
   756      *              field is either inaccessible or final.
   757      * @exception IllegalArgumentException  if the specified object is not an
   758      *              instance of the class or interface declaring the underlying
   759      *              field (or a subclass or implementor thereof),
   760      *              or if an unwrapping conversion fails.
   761      * @exception NullPointerException      if the specified object is null
   762      *              and the field is an instance field.
   763      * @exception ExceptionInInitializerError if the initialization provoked
   764      *              by this method fails.
   765      * @see       Field#set
   766      */
   767     public void setChar(Object obj, char c)
   768         throws IllegalArgumentException, IllegalAccessException
   769     {
   770         getFieldAccessor(obj).setChar(obj, c);
   771     }
   772 
   773     /**
   774      * Sets the value of a field as a {@code short} on the specified object.
   775      * This method is equivalent to
   776      * {@code set(obj, sObj)},
   777      * where {@code sObj} is a {@code Short} object and
   778      * {@code sObj.shortValue() == s}.
   779      *
   780      * @param obj the object whose field should be modified
   781      * @param s   the new value for the field of {@code obj}
   782      * being modified
   783      *
   784      * @exception IllegalAccessException    if this {@code Field} object
   785      *              is enforcing Java language access control and the underlying
   786      *              field is either inaccessible or final.
   787      * @exception IllegalArgumentException  if the specified object is not an
   788      *              instance of the class or interface declaring the underlying
   789      *              field (or a subclass or implementor thereof),
   790      *              or if an unwrapping conversion fails.
   791      * @exception NullPointerException      if the specified object is null
   792      *              and the field is an instance field.
   793      * @exception ExceptionInInitializerError if the initialization provoked
   794      *              by this method fails.
   795      * @see       Field#set
   796      */
   797     public void setShort(Object obj, short s)
   798         throws IllegalArgumentException, IllegalAccessException
   799     {
   800         getFieldAccessor(obj).setShort(obj, s);
   801     }
   802 
   803     /**
   804      * Sets the value of a field as an {@code int} on the specified object.
   805      * This method is equivalent to
   806      * {@code set(obj, iObj)},
   807      * where {@code iObj} is a {@code Integer} object and
   808      * {@code iObj.intValue() == i}.
   809      *
   810      * @param obj the object whose field should be modified
   811      * @param i   the new value for the field of {@code obj}
   812      * being modified
   813      *
   814      * @exception IllegalAccessException    if this {@code Field} object
   815      *              is enforcing Java language access control and the underlying
   816      *              field is either inaccessible or final.
   817      * @exception IllegalArgumentException  if the specified object is not an
   818      *              instance of the class or interface declaring the underlying
   819      *              field (or a subclass or implementor thereof),
   820      *              or if an unwrapping conversion fails.
   821      * @exception NullPointerException      if the specified object is null
   822      *              and the field is an instance field.
   823      * @exception ExceptionInInitializerError if the initialization provoked
   824      *              by this method fails.
   825      * @see       Field#set
   826      */
   827     public void setInt(Object obj, int i)
   828         throws IllegalArgumentException, IllegalAccessException
   829     {
   830         getFieldAccessor(obj).setInt(obj, i);
   831     }
   832 
   833     /**
   834      * Sets the value of a field as a {@code long} on the specified object.
   835      * This method is equivalent to
   836      * {@code set(obj, lObj)},
   837      * where {@code lObj} is a {@code Long} object and
   838      * {@code lObj.longValue() == l}.
   839      *
   840      * @param obj the object whose field should be modified
   841      * @param l   the new value for the field of {@code obj}
   842      * being modified
   843      *
   844      * @exception IllegalAccessException    if this {@code Field} object
   845      *              is enforcing Java language access control and the underlying
   846      *              field is either inaccessible or final.
   847      * @exception IllegalArgumentException  if the specified object is not an
   848      *              instance of the class or interface declaring the underlying
   849      *              field (or a subclass or implementor thereof),
   850      *              or if an unwrapping conversion fails.
   851      * @exception NullPointerException      if the specified object is null
   852      *              and the field is an instance field.
   853      * @exception ExceptionInInitializerError if the initialization provoked
   854      *              by this method fails.
   855      * @see       Field#set
   856      */
   857     public void setLong(Object obj, long l)
   858         throws IllegalArgumentException, IllegalAccessException
   859     {
   860         getFieldAccessor(obj).setLong(obj, l);
   861     }
   862 
   863     /**
   864      * Sets the value of a field as a {@code float} on the specified object.
   865      * This method is equivalent to
   866      * {@code set(obj, fObj)},
   867      * where {@code fObj} is a {@code Float} object and
   868      * {@code fObj.floatValue() == f}.
   869      *
   870      * @param obj the object whose field should be modified
   871      * @param f   the new value for the field of {@code obj}
   872      * being modified
   873      *
   874      * @exception IllegalAccessException    if this {@code Field} object
   875      *              is enforcing Java language access control and the underlying
   876      *              field is either inaccessible or final.
   877      * @exception IllegalArgumentException  if the specified object is not an
   878      *              instance of the class or interface declaring the underlying
   879      *              field (or a subclass or implementor thereof),
   880      *              or if an unwrapping conversion fails.
   881      * @exception NullPointerException      if the specified object is null
   882      *              and the field is an instance field.
   883      * @exception ExceptionInInitializerError if the initialization provoked
   884      *              by this method fails.
   885      * @see       Field#set
   886      */
   887     public void setFloat(Object obj, float f)
   888         throws IllegalArgumentException, IllegalAccessException
   889     {
   890         getFieldAccessor(obj).setFloat(obj, f);
   891     }
   892 
   893     /**
   894      * Sets the value of a field as a {@code double} on the specified object.
   895      * This method is equivalent to
   896      * {@code set(obj, dObj)},
   897      * where {@code dObj} is a {@code Double} object and
   898      * {@code dObj.doubleValue() == d}.
   899      *
   900      * @param obj the object whose field should be modified
   901      * @param d   the new value for the field of {@code obj}
   902      * being modified
   903      *
   904      * @exception IllegalAccessException    if this {@code Field} object
   905      *              is enforcing Java language access control and the underlying
   906      *              field is either inaccessible or final.
   907      * @exception IllegalArgumentException  if the specified object is not an
   908      *              instance of the class or interface declaring the underlying
   909      *              field (or a subclass or implementor thereof),
   910      *              or if an unwrapping conversion fails.
   911      * @exception NullPointerException      if the specified object is null
   912      *              and the field is an instance field.
   913      * @exception ExceptionInInitializerError if the initialization provoked
   914      *              by this method fails.
   915      * @see       Field#set
   916      */
   917     public void setDouble(Object obj, double d)
   918         throws IllegalArgumentException, IllegalAccessException
   919     {
   920         getFieldAccessor(obj).setDouble(obj, d);
   921     }
   922 
   923     // Convenience routine which performs security checks
   924     private FieldAccessor getFieldAccessor(Object obj)
   925         throws IllegalAccessException
   926     {
   927         doSecurityCheck(obj);
   928         boolean ov = override;
   929         FieldAccessor a = (ov)? overrideFieldAccessor : fieldAccessor;
   930         return (a != null)? a : acquireFieldAccessor(ov);
   931     }
   932 
   933     // NOTE that there is no synchronization used here. It is correct
   934     // (though not efficient) to generate more than one FieldAccessor
   935     // for a given Field. However, avoiding synchronization will
   936     // probably make the implementation more scalable.
   937     private FieldAccessor acquireFieldAccessor(boolean overrideFinalCheck) {
   938         // First check to see if one has been created yet, and take it
   939         // if so
   940         FieldAccessor tmp = null;
   941         if (root != null) tmp = root.getFieldAccessor(overrideFinalCheck);
   942         if (tmp != null) {
   943             if (overrideFinalCheck)
   944                 overrideFieldAccessor = tmp;
   945             else
   946                 fieldAccessor = tmp;
   947         } else {
   948             // Otherwise fabricate one and propagate it up to the root
   949             tmp = reflectionFactory.newFieldAccessor(this, overrideFinalCheck);
   950             setFieldAccessor(tmp, overrideFinalCheck);
   951         }
   952 
   953         return tmp;
   954     }
   955 
   956     // Returns FieldAccessor for this Field object, not looking up
   957     // the chain to the root
   958     private FieldAccessor getFieldAccessor(boolean overrideFinalCheck) {
   959         return (overrideFinalCheck)? overrideFieldAccessor : fieldAccessor;
   960     }
   961 
   962     // Sets the FieldAccessor for this Field object and
   963     // (recursively) its root
   964     private void setFieldAccessor(FieldAccessor accessor, boolean overrideFinalCheck) {
   965         if (overrideFinalCheck)
   966             overrideFieldAccessor = accessor;
   967         else
   968             fieldAccessor = accessor;
   969         // Propagate up
   970         if (root != null) {
   971             root.setFieldAccessor(accessor, overrideFinalCheck);
   972         }
   973     }
   974 
   975     // NOTE: be very careful if you change the stack depth of this
   976     // routine. The depth of the "getCallerClass" call is hardwired so
   977     // that the compiler can have an easier time if this gets inlined.
   978     private void doSecurityCheck(Object obj) throws IllegalAccessException {
   979         if (!override) {
   980             if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {
   981                 Class<?> caller = Reflection.getCallerClass(4);
   982 
   983                 checkAccess(caller, clazz, obj, modifiers);
   984             }
   985         }
   986     }
   987 
   988     /*
   989      * Utility routine to paper over array type names
   990      */
   991     static String getTypeName(Class<?> type) {
   992         if (type.isArray()) {
   993             try {
   994                 Class<?> cl = type;
   995                 int dimensions = 0;
   996                 while (cl.isArray()) {
   997                     dimensions++;
   998                     cl = cl.getComponentType();
   999                 }
  1000                 StringBuffer sb = new StringBuffer();
  1001                 sb.append(cl.getName());
  1002                 for (int i = 0; i < dimensions; i++) {
  1003                     sb.append("[]");
  1004                 }
  1005                 return sb.toString();
  1006             } catch (Throwable e) { /*FALLTHRU*/ }
  1007         }
  1008         return type.getName();
  1009     }
  1010 
  1011     /**
  1012      * @throws NullPointerException {@inheritDoc}
  1013      * @since 1.5
  1014      */
  1015     public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
  1016         if (annotationClass == null)
  1017             throw new NullPointerException();
  1018 
  1019         return (T) declaredAnnotations().get(annotationClass);
  1020     }
  1021 
  1022     /**
  1023      * @since 1.5
  1024      */
  1025     public Annotation[] getDeclaredAnnotations()  {
  1026         return AnnotationParser.toArray(declaredAnnotations());
  1027     }
  1028 
  1029     private transient Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
  1030 
  1031     private synchronized  Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {
  1032         if (declaredAnnotations == null) {
  1033             declaredAnnotations = AnnotationParser.parseAnnotations(
  1034                 annotations, sun.misc.SharedSecrets.getJavaLangAccess().
  1035                 getConstantPool(getDeclaringClass()),
  1036                 getDeclaringClass());
  1037         }
  1038         return declaredAnnotations;
  1039     }
  1040 }