/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999-2007 Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.bytecode;
import javassist.CtClass;
import javassist.bytecode.annotation.AnnotationsWriter;
import javassist.bytecode.annotation.MemberValue;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Map;
/**
* A class representing <code>AnnotationDefault_attribute</code>.
*
* <p>For example, if you declare the following annotation type:
*
* <ul><pre>
* @interface Author {
* String name() default "Shakespeare";
* int age() default 99;
* }
* </pre></ul>
*
* <p>The defautl values of <code>name</code> and <code>age</code>
* are stored as annotation default attributes in <code>Author.class</code>.
* The following code snippet obtains the default value of <code>name</code>:
*
* <ul><pre>
* ClassPool pool = ...
* CtClass cc = pool.get("Author");
* CtMethod cm = cc.getDeclaredMethod("age");
* MethodInfo minfo = cm.getMethodInfo();
* AnnotationDefaultAttribute ada
* = (AnnotationDefaultAttribute)
* minfo.getAttribute(AnnotationDefaultAttribute.tag);
* MemberValue value = ada.getDefaultValue()); // default value of age
* </pre></ul>
*
* <p>If the following statement is executed after the code above,
* the default value of age is set to 80:
*
* <ul><pre>
* ada.setDefaultValue(new IntegerMemberValue(minfo.getConstPool(), 80));
* </pre></ul>
*
* @see AnnotationsAttribute
* @see javassist.bytecode.annotation.MemberValue
*/
public class AnnotationDefaultAttribute extends AttributeInfo {
/**
* The name of the <code>AnnotationDefault</code> attribute.
*/
public static final String tag = "AnnotationDefault";
/**
* Constructs an <code>AnnotationDefault_attribute</code>.
*
* @param cp constant pool
* @param info the contents of this attribute. It does not
* include <code>attribute_name_index</code> or
* <code>attribute_length</code>.
*/
public AnnotationDefaultAttribute(ConstPool cp, byte[] info) {
super(cp, tag, info);
}
/**
* Constructs an empty <code>AnnotationDefault_attribute</code>.
* The default value can be set by <code>setDefaultValue()</code>.
*
* @param cp constant pool
* @see #setDefaultValue(javassist.bytecode.annotation.MemberValue)
*/
public AnnotationDefaultAttribute(ConstPool cp) {
this(cp, new byte[] { 0, 0 });
}
/**
* @param n the attribute name.
*/
AnnotationDefaultAttribute(ConstPool cp, int n, DataInputStream in)
throws IOException
{
super(cp, n, in);
}
/**
* Copies this attribute and returns a new copy.
*/
public AttributeInfo copy(ConstPool newCp, Map classnames) {
AnnotationsAttribute.Copier copier
= new AnnotationsAttribute.Copier(info, constPool, newCp, classnames);
try {
copier.memberValue(0);
return new AnnotationDefaultAttribute(newCp, copier.close());
}
catch (Exception e) {
throw new RuntimeException(e.toString());
}
}
/**
* Obtains the default value represented by this attribute.
*/
public MemberValue getDefaultValue()
{
try {
return new AnnotationsAttribute.Parser(info, constPool)
.parseMemberValue();
}
catch (Exception e) {
throw new RuntimeException(e.toString());
}
}
/**
* Changes the default value represented by this attribute.
*
* @param value the new value.
* @see javassist.bytecode.annotation.Annotation#createMemberValue(ConstPool, CtClass)
*/
public void setDefaultValue(MemberValue value) {
ByteArrayOutputStream output = new ByteArrayOutputStream();
AnnotationsWriter writer = new AnnotationsWriter(output, constPool);
try {
value.write(writer);
writer.close();
}
catch (IOException e) {
throw new RuntimeException(e); // should never reach here.
}
set(output.toByteArray());
}
/**
* Returns a string representation of this object.
*/
public String toString() {
return getDefaultValue().toString();
}
}