    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.classfile;
    020
    021import java.io.DataInput;
    022import java.io.DataOutputStream;
    023import java.io.IOException;
    024
    025import org.apache.bcel.Const;
    026import org.apache.bcel.util.Args;
    027
    028/**
    029 * This attribute exists for local or anonymous classes and ... there can be only one.
    030 *
    031 * @since 6.0
    032 */
    033public class EnclosingMethod extends Attribute {
    034
    035    // Pointer to the CONSTANT_Class_info structure representing the
    036    // innermost class that encloses the declaration of the current class.
    037    private int classIndex;
    038
    039    // If the current class is not immediately enclosed by a method or
    040    // constructor, then the value of the method_index item must be zero.
    041    // Otherwise, the value of the method_index item must point to a
    042    // CONSTANT_NameAndType_info structure representing the name and the
    043    // type of a method in the class referenced by the class we point
    044    // to in the class_index. *It is the compiler responsibility* to
    045    // ensure that the method identified by this index is the closest
    046    // lexically enclosing method that includes the local/anonymous class.
    047    private int methodIndex;
    048
    049    // Ctors - and code to read an attribute in.
    050    EnclosingMethod(final int nameIndex, final int len, final DataInput input, final ConstantPool cpool) throws IOException {
    051        this(nameIndex, len, input.readUnsignedShort(), input.readUnsignedShort(), cpool);
    052    }
    053
    054    private EnclosingMethod(final int nameIndex, final int len, final int classIndex, final int methodIndex, final ConstantPool cpool) {
    055        super(Const.ATTR_ENCLOSING_METHOD, nameIndex, Args.require(len, 4, "EnclosingMethod attribute length"), cpool);
    056        this.classIndex = Args.requireU2(classIndex, 0, cpool.getLength(), "EnclosingMethod class index");
    057        this.methodIndex = Args.requireU2(methodIndex, "EnclosingMethod method index");
    058    }
    059
    060    @Override
    061    public void accept(final Visitor v) {
    062        v.visitEnclosingMethod(this);
    063    }
    064
    065    @Override
    066    public Attribute copy(final ConstantPool constantPool) {
    067        return (Attribute) clone();
    068    }
    069
    070    @Override
    071    public final void dump(final DataOutputStream file) throws IOException {
    072        super.dump(file);
    073        file.writeShort(classIndex);
    074        file.writeShort(methodIndex);
    075    }
    076
    077    /**
    078     * Gets the enclosing class.
    079     *
    080     * @return the enclosing class.
    081     */
    082    public final ConstantClass getEnclosingClass() {
    083        return super.getConstantPool().getConstant(classIndex, Const.CONSTANT_Class, ConstantClass.class);
    084    }
    085
    086    /**
    087     * Gets the enclosing class index.
    088     *
    089     * @return the enclosing class index.
    090     */
    091    public final int getEnclosingClassIndex() {
    092        return classIndex;
    093    }
    094
    095    /**
    096     * Gets the enclosing method.
    097     *
    098     * @return the enclosing method.
    099     */
    100    public final ConstantNameAndType getEnclosingMethod() {
    101        if (methodIndex == 0) {
    102            return null;
    103        }
    104        return super.getConstantPool().getConstant(methodIndex, Const.CONSTANT_NameAndType, ConstantNameAndType.class);
    105    }
    106
    107    /**
    108     * Gets the enclosing method index.
    109     *
    110     * @return the enclosing method index.
    111     */
    112    public final int getEnclosingMethodIndex() {
    113        return methodIndex;
    114    }
    115
    116    /**
    117     * Sets the enclosing class index.
    118     *
    119     * @param idx the index.
    120     */
    121    public final void setEnclosingClassIndex(final int idx) {
    122        classIndex = idx;
    123    }
    124
    125    /**
    126     * Sets the enclosing method index.
    127     *
    128     * @param idx the index.
    129     */
    130    public final void setEnclosingMethodIndex(final int idx) {
    131        methodIndex = idx;
    132    }
    133}