    001/**
    002 *  Licensed to the Apache Software Foundation (ASF) under one or more
    003 *  contributor license agreements.  See the NOTICE file distributed with
    004 *  this work for additional information regarding copyright ownership.
    005 *  The ASF licenses this file to You under the Apache License, Version 2.0
    006 *  (the "License"); you may not use this file except in compliance with
    007 *  the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017package org.apache.bcel.classfile;
    018
    019import java.io.DataInput;
    020import java.io.DataOutputStream;
    021import java.io.IOException;
    022
    023import org.apache.bcel.Const;
    024import org.apache.bcel.util.Args;
    025
    026/**
    027 * This attribute exists for local or anonymous classes and ... there can be only one.
    028 *
    029 * @since 6.0
    030 */
    031public class EnclosingMethod extends Attribute {
    032
    033    // Pointer to the CONSTANT_Class_info structure representing the
    034    // innermost class that encloses the declaration of the current class.
    035    private int classIndex;
    036
    037    // If the current class is not immediately enclosed by a method or
    038    // constructor, then the value of the method_index item must be zero.
    039    // Otherwise, the value of the method_index item must point to a
    040    // CONSTANT_NameAndType_info structure representing the name and the
    041    // type of a method in the class referenced by the class we point
    042    // to in the class_index. *It is the compiler responsibility* to
    043    // ensure that the method identified by this index is the closest
    044    // lexically enclosing method that includes the local/anonymous class.
    045    private int methodIndex;
    046
    047    // Ctors - and code to read an attribute in.
    048    EnclosingMethod(final int nameIndex, final int len, final DataInput input, final ConstantPool cpool) throws IOException {
    049        this(nameIndex, len, input.readUnsignedShort(), input.readUnsignedShort(), cpool);
    050    }
    051
    052    private EnclosingMethod(final int nameIndex, final int len, final int classIndex, final int methodIndex, final ConstantPool cpool) {
    053        super(Const.ATTR_ENCLOSING_METHOD, nameIndex, Args.require(len, 4, "EnclosingMethod attribute length"), cpool);
    054        this.classIndex = Args.requireU2(classIndex, 0, cpool.getLength(), "EnclosingMethod class index");
    055        this.methodIndex = Args.requireU2(methodIndex, "EnclosingMethod method index");
    056    }
    057
    058    @Override
    059    public void accept(final Visitor v) {
    060        v.visitEnclosingMethod(this);
    061    }
    062
    063    @Override
    064    public Attribute copy(final ConstantPool constantPool) {
    065        return (Attribute) clone();
    066    }
    067
    068    @Override
    069    public final void dump(final DataOutputStream file) throws IOException {
    070        super.dump(file);
    071        file.writeShort(classIndex);
    072        file.writeShort(methodIndex);
    073    }
    074
    075    public final ConstantClass getEnclosingClass() {
    076        return super.getConstantPool().getConstant(classIndex, Const.CONSTANT_Class, ConstantClass.class);
    077    }
    078
    079    // Accessors
    080    public final int getEnclosingClassIndex() {
    081        return classIndex;
    082    }
    083
    084    public final ConstantNameAndType getEnclosingMethod() {
    085        if (methodIndex == 0) {
    086            return null;
    087        }
    088        return super.getConstantPool().getConstant(methodIndex, Const.CONSTANT_NameAndType, ConstantNameAndType.class);
    089    }
    090
    091    public final int getEnclosingMethodIndex() {
    092        return methodIndex;
    093    }
    094
    095    public final void setEnclosingClassIndex(final int idx) {
    096        classIndex = idx;
    097    }
    098
    099    public final void setEnclosingMethodIndex(final int idx) {
    100        methodIndex = idx;
    101    }
    102}