/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- 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,
* or the Apache License Version 2.0.
*
* 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:
*
* <pre>
* @interface Author {
* String name() default "Shakespeare";
* int age() default 99;
* }
* </pre>
*
* <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>:
*
* <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>
*
* <p>If the following statement is executed after the code above,
* the default value of age is set to 80:
*
* <pre>
* ada.setDefaultValue(new IntegerMemberValue(minfo.getConstPool(), 80));
* </pre>
*
* @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();
}
}