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/*
 * 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 AnnotationDefault_attribute.
 *
 * 

For example, if you declare the following annotation type: * *

     * @interface Author {
     *   String name() default "Shakespeare";
     *   int age() default 99;
     * }
     * 
* *

The defautl values of name and age * are stored as annotation default attributes in Author.class. * The following code snippet obtains the default value of name: * *

     * 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
     * 
* *

If the following statement is executed after the code above, * the default value of age is set to 80: * *

     * ada.setDefaultValue(new IntegerMemberValue(minfo.getConstPool(), 80));
     * 
* * @see AnnotationsAttribute * @see javassist.bytecode.annotation.MemberValue */ public class AnnotationDefaultAttribute extends AttributeInfo { /** * The name of the AnnotationDefault attribute. */ public static final String tag = "AnnotationDefault"; /** * Constructs an AnnotationDefault_attribute. * * @param cp constant pool * @param info the contents of this attribute. It does not * include attribute_name_index or * attribute_length. */ public AnnotationDefaultAttribute(ConstPool cp, byte[] info) { super(cp, tag, info); } /** * Constructs an empty AnnotationDefault_attribute. * The default value can be set by setDefaultValue(). * * @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(); } }




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