+/* java.lang.reflect.Field - reflection of Java fields
+ Copyright (C) 1998, 2001 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;
+
+/**
+ * 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;
+
+ /**
+ * 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;
+ }
+
+ /**
+ * 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 native int getModifiers();
+
+ /**
+ * 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
+ StringBuffer sb = new StringBuffer(64);
+ Modifier.toString(getModifiers(), sb).append(' ');
+ sb.append(getType().getName()).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;
+}