| /* java.lang.reflect.Field - reflection of Java fields |
| Copyright (C) 1998, 2001, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.lang.reflect; |
| |
| import gnu.java.lang.ClassHelper; |
| |
| import gnu.java.lang.reflect.FieldSignatureParser; |
| |
| /** |
| * The Field class represents a member variable of a class. It also allows |
| * dynamic access to a member, via reflection. This works for both |
| * static and instance fields. Operations on Field objects know how to |
| * do widening conversions, but throw {@link IllegalArgumentException} if |
| * a narrowing conversion would be necessary. You can query for information |
| * on this Field regardless of location, but get and set access may be limited |
| * by Java language access controls. If you can't do it in the compiler, you |
| * can't normally do it here either.<p> |
| * |
| * <B>Note:</B> This class returns and accepts types as Classes, even |
| * primitive types; there are Class types defined that represent each |
| * different primitive type. They are <code>java.lang.Boolean.TYPE, |
| * java.lang.Byte.TYPE,</code>, also available as <code>boolean.class, |
| * byte.class</code>, etc. These are not to be confused with the |
| * classes <code>java.lang.Boolean, java.lang.Byte</code>, etc., which are |
| * real classes.<p> |
| * |
| * Also note that this is not a serializable class. It is entirely feasible |
| * to make it serializable using the Externalizable interface, but this is |
| * on Sun, not me. |
| * |
| * @author John Keiser |
| * @author Eric Blake <ebb9@email.byu.edu> |
| * @see Member |
| * @see Class |
| * @see Class#getField(String) |
| * @see Class#getDeclaredField(String) |
| * @see Class#getFields() |
| * @see Class#getDeclaredFields() |
| * @since 1.1 |
| * @status updated to 1.4 |
| */ |
| public final class Field |
| extends AccessibleObject implements Member |
| { |
| private Class declaringClass; |
| private String name; |
| private int slot; |
| |
| private static final int FIELD_MODIFIERS |
| = Modifier.FINAL | Modifier.PRIVATE | Modifier.PROTECTED |
| | Modifier.PUBLIC | Modifier.STATIC | Modifier.TRANSIENT |
| | Modifier.VOLATILE; |
| |
| /** |
| * This class is uninstantiable except natively. |
| */ |
| private Field(Class declaringClass, String name, int slot) |
| { |
| this.declaringClass = declaringClass; |
| this.name = name; |
| this.slot = slot; |
| } |
| |
| /** |
| * Gets the class that declared this field, or the class where this field |
| * is a non-inherited member. |
| * @return the class that declared this member |
| */ |
| public Class getDeclaringClass() |
| { |
| return declaringClass; |
| } |
| |
| /** |
| * Gets the name of this field. |
| * @return the name of this field |
| */ |
| public String getName() |
| { |
| return name; |
| } |
| |
| /** |
| * Return the raw modifiers for this field. |
| * @return the field's modifiers |
| */ |
| private native int getModifiersInternal(); |
| |
| /** |
| * Gets the modifiers this field uses. Use the <code>Modifier</code> |
| * class to interpret the values. A field can only have a subset of the |
| * following modifiers: public, private, protected, static, final, |
| * transient, and volatile. |
| * |
| * @return an integer representing the modifiers to this Member |
| * @see Modifier |
| */ |
| public int getModifiers() |
| { |
| return getModifiersInternal() & FIELD_MODIFIERS; |
| } |
| |
| /** |
| * Return true if this field is synthetic, false otherwise. |
| * @since 1.5 |
| */ |
| public boolean isSynthetic() |
| { |
| return (getModifiersInternal() & Modifier.SYNTHETIC) != 0; |
| } |
| |
| /** |
| * Return true if this field represents an enum constant, |
| * false otherwise. |
| * @since 1.5 |
| */ |
| public boolean isEnumConstant() |
| { |
| return (getModifiersInternal() & Modifier.ENUM) != 0; |
| } |
| |
| /** |
| * Gets the type of this field. |
| * @return the type of this field |
| */ |
| public native Class getType(); |
| |
| /** |
| * Compare two objects to see if they are semantically equivalent. |
| * Two Fields are semantically equivalent if they have the same declaring |
| * class, name, and type. Since you can't creat a Field except through |
| * the VM, this is just the == relation. |
| * |
| * @param o the object to compare to |
| * @return <code>true</code> if they are equal; <code>false</code> if not |
| */ |
| public boolean equals(Object o) |
| { |
| if (!(o instanceof Field)) |
| return false; |
| Field that = (Field)o; |
| if (this.getDeclaringClass() != that.getDeclaringClass()) |
| return false; |
| if (!this.getName().equals(that.getName())) |
| return false; |
| if (this.getType() != that.getType()) |
| return false; |
| return true; |
| } |
| |
| /** |
| * Get the hash code for the Field. The Field hash code is the hash code |
| * of its name XOR'd with the hash code of its class name. |
| * |
| * @return the hash code for the object. |
| */ |
| public int hashCode() |
| { |
| return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); |
| } |
| |
| /** |
| * Get a String representation of the Field. A Field's String |
| * representation is "<modifiers> <type> |
| * <class>.<fieldname>".<br> Example: |
| * <code>public transient boolean gnu.parse.Parser.parseComplete</code> |
| * |
| * @return the String representation of the Field |
| */ |
| public String toString() |
| { |
| // 64 is a reasonable buffer initial size for field |
| StringBuilder sb = new StringBuilder(64); |
| Modifier.toString(getModifiers(), sb).append(' '); |
| sb.append(ClassHelper.getUserName(getType())).append(' '); |
| sb.append(getDeclaringClass().getName()).append('.'); |
| sb.append(getName()); |
| return sb.toString(); |
| } |
| |
| public String toGenericString() |
| { |
| StringBuilder sb = new StringBuilder(64); |
| Modifier.toString(getModifiers(), sb).append(' '); |
| sb.append(getGenericType()).append(' '); |
| sb.append(getDeclaringClass().getName()).append('.'); |
| sb.append(getName()); |
| return sb.toString(); |
| } |
| |
| /** |
| * Get the value of this Field. If it is primitive, it will be wrapped |
| * in the appropriate wrapper type (boolean = java.lang.Boolean).<p> |
| * |
| * If the field is static, <code>o</code> will be ignored. Otherwise, if |
| * <code>o</code> is null, you get a <code>NullPointerException</code>, |
| * and if it is incompatible with the declaring class of the field, you |
| * get an <code>IllegalArgumentException</code>.<p> |
| * |
| * Next, if this Field enforces access control, your runtime context is |
| * evaluated, and you may have an <code>IllegalAccessException</code> if |
| * you could not access this field in similar compiled code. If the field |
| * is static, and its class is uninitialized, you trigger class |
| * initialization, which may end in a |
| * <code>ExceptionInInitializerError</code>.<p> |
| * |
| * Finally, the field is accessed, and primitives are wrapped (but not |
| * necessarily in new objects). This method accesses the field of the |
| * declaring class, even if the instance passed in belongs to a subclass |
| * which declares another field to hide this one. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if <code>o</code> is not an instance of |
| * the class or interface declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #getBoolean(Object) |
| * @see #getByte(Object) |
| * @see #getChar(Object) |
| * @see #getShort(Object) |
| * @see #getInt(Object) |
| * @see #getLong(Object) |
| * @see #getFloat(Object) |
| * @see #getDouble(Object) |
| */ |
| public native Object get(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this boolean Field. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a boolean field of |
| * <code>o</code>, or if <code>o</code> is not an instance of the |
| * declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native boolean getBoolean(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this byte Field. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte field of |
| * <code>o</code>, or if <code>o</code> is not an instance of the |
| * declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native byte getByte(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as a char. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a char field of |
| * <code>o</code>, or if <code>o</code> is not an instance |
| * of the declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native char getChar(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as a short. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte or short |
| * field of <code>o</code>, or if <code>o</code> is not an instance |
| * of the declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native short getShort(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as an int. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte, short, char, or |
| * int field of <code>o</code>, or if <code>o</code> is not an |
| * instance of the declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native int getInt(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as a long. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte, short, char, int, |
| * or long field of <code>o</code>, or if <code>o</code> is not an |
| * instance of the declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native long getLong(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as a float. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte, short, char, int, |
| * long, or float field of <code>o</code>, or if <code>o</code> is |
| * not an instance of the declaring class of this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native float getFloat(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Get the value of this Field as a double. If the field is static, |
| * <code>o</code> will be ignored. |
| * |
| * @param o the object to get the value of this Field from |
| * @return the value of the Field |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte, short, char, int, |
| * long, float, or double field of <code>o</code>, or if |
| * <code>o</code> is not an instance of the declaring class of this |
| * field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #get(Object) |
| */ |
| public native double getDouble(Object o) |
| throws IllegalAccessException; |
| |
| /** |
| * Set the value of this Field. If it is a primitive field, the value |
| * will be unwrapped from the passed object (boolean = java.lang.Boolean).<p> |
| * |
| * If the field is static, <code>o</code> will be ignored. Otherwise, if |
| * <code>o</code> is null, you get a <code>NullPointerException</code>, |
| * and if it is incompatible with the declaring class of the field, you |
| * get an <code>IllegalArgumentException</code>.<p> |
| * |
| * Next, if this Field enforces access control, your runtime context is |
| * evaluated, and you may have an <code>IllegalAccessException</code> if |
| * you could not access this field in similar compiled code. This also |
| * occurs whether or not there is access control if the field is final. |
| * If the field is primitive, and unwrapping your argument fails, you will |
| * get an <code>IllegalArgumentException</code>; likewise, this error |
| * happens if <code>value</code> cannot be cast to the correct object type. |
| * If the field is static, and its class is uninitialized, you trigger class |
| * initialization, which may end in a |
| * <code>ExceptionInInitializerError</code>.<p> |
| * |
| * Finally, the field is set with the widened value. This method accesses |
| * the field of the declaring class, even if the instance passed in belongs |
| * to a subclass which declares another field to hide this one. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if <code>value</code> cannot be |
| * converted by a widening conversion to the underlying type of |
| * the Field, or if <code>o</code> is not an instance of the class |
| * declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #setBoolean(Object, boolean) |
| * @see #setByte(Object, byte) |
| * @see #setChar(Object, char) |
| * @see #setShort(Object, short) |
| * @see #setInt(Object, int) |
| * @see #setLong(Object, long) |
| * @see #setFloat(Object, float) |
| * @see #setDouble(Object, double) |
| */ |
| public native void set(Object o, Object value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this boolean Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a boolean field, or if |
| * <code>o</code> is not an instance of the class declaring this |
| * field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setBoolean(Object o, boolean value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this byte Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a byte, short, int, long, |
| * float, or double field, or if <code>o</code> is not an instance |
| * of the class declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setByte(Object o, byte value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this char Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a char, int, long, |
| * float, or double field, or if <code>o</code> is not an instance |
| * of the class declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setChar(Object o, char value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this short Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a short, int, long, |
| * float, or double field, or if <code>o</code> is not an instance |
| * of the class declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setShort(Object o, short value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this int Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not an int, long, float, or |
| * double field, or if <code>o</code> is not an instance of the |
| * class declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setInt(Object o, int value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this long Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a long, float, or double |
| * field, or if <code>o</code> is not an instance of the class |
| * declaring this field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setLong(Object o, long value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this float Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a float or long field, or |
| * if <code>o</code> is not an instance of the class declaring this |
| * field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setFloat(Object o, float value) |
| throws IllegalAccessException; |
| |
| /** |
| * Set this double Field. If the field is static, <code>o</code> will be |
| * ignored. |
| * |
| * @param o the object to set this Field on |
| * @param value the value to set this Field to |
| * @throws IllegalAccessException if you could not normally access this field |
| * (i.e. it is not public) |
| * @throws IllegalArgumentException if this is not a double field, or if |
| * <code>o</code> is not an instance of the class declaring this |
| * field |
| * @throws NullPointerException if <code>o</code> is null and this field |
| * requires an instance |
| * @throws ExceptionInInitializerError if accessing a static field triggered |
| * class initialization, which then failed |
| * @see #set(Object, Object) |
| */ |
| public native void setDouble(Object o, double value) |
| throws IllegalAccessException; |
| |
| /** |
| * Return the generic type of the field. If the field type is not a generic |
| * type, the method returns the same as <code>getType()</code>. |
| * |
| * @throws GenericSignatureFormatError if the generic signature does |
| * not conform to the format specified in the Virtual Machine |
| * specification, version 3. |
| * @since 1.5 |
| */ |
| public Type getGenericType() |
| { |
| String signature = getSignature(); |
| if (signature == null) |
| return getType(); |
| FieldSignatureParser p = new FieldSignatureParser(getDeclaringClass(), |
| signature); |
| return p.getFieldType(); |
| } |
| |
| /** |
| * Return the String in the Signature attribute for this field. If there |
| * is no Signature attribute, return null. |
| */ |
| private native String getSignature(); |
| |
| } |