    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.generic;
    018
    019import org.apache.bcel.Const;
    020import org.apache.bcel.classfile.ConstantCP;
    021import org.apache.bcel.classfile.ConstantNameAndType;
    022import org.apache.bcel.classfile.ConstantPool;
    023import org.apache.bcel.classfile.ConstantUtf8;
    024import org.apache.bcel.classfile.Utility;
    025
    026/**
    027 * Super class for InvokeInstruction and FieldInstruction, since they have some methods in common!
    028 */
    029public abstract class FieldOrMethod extends CPInstruction implements LoadClass {
    030
    031    /**
    032     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    033     */
    034    FieldOrMethod() {
    035        // no init
    036    }
    037
    038    /**
    039     * @param index to constant pool
    040     */
    041    protected FieldOrMethod(final short opcode, final int index) {
    042        super(opcode, index);
    043    }
    044
    045    /**
    046     * @return name of the referenced class/interface
    047     * @deprecated If the instruction references an array class, this method will return "java.lang.Object". For code
    048     *             generated by Java 1.5, this answer is sometimes wrong (e.g., if the "clone()" method is called on an
    049     *             array). A better idea is to use the {@link #getReferenceType(ConstantPoolGen)} method, which correctly
    050     *             distinguishes between class types and array types.
    051     *
    052     */
    053    @Deprecated
    054    public String getClassName(final ConstantPoolGen cpg) {
    055        final ConstantPool cp = cpg.getConstantPool();
    056        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    057        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    058        if (className.startsWith("[")) {
    059            // Turn array classes into java.lang.Object.
    060            return "java.lang.Object";
    061        }
    062        return Utility.pathToPackage(className);
    063    }
    064
    065    /**
    066     * @return type of the referenced class/interface
    067     * @deprecated If the instruction references an array class, the ObjectType returned will be invalid. Use
    068     *             getReferenceType() instead.
    069     */
    070    @Deprecated
    071    public ObjectType getClassType(final ConstantPoolGen cpg) {
    072        return ObjectType.getInstance(getClassName(cpg));
    073    }
    074
    075    /**
    076     * Gets the ObjectType of the method return or field.
    077     *
    078     * @return type of the referenced class/interface
    079     * @throws ClassGenException when the field is (or method returns) an array,
    080     */
    081    @Override
    082    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
    083        final ReferenceType rt = getReferenceType(cpg);
    084        if (rt instanceof ObjectType) {
    085            return (ObjectType) rt;
    086        }
    087        throw new ClassGenException(rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
    088    }
    089
    090    /**
    091     * @return name of referenced method/field.
    092     */
    093    public String getName(final ConstantPoolGen cpg) {
    094        final ConstantPool cp = cpg.getConstantPool();
    095        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    096        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    097        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
    098    }
    099
    100    /**
    101     * Gets the reference type representing the class, interface, or array class referenced by the instruction.
    102     *
    103     * @param cpg the ConstantPoolGen used to create the instruction
    104     * @return an ObjectType (if the referenced class type is a class or interface), or an ArrayType (if the referenced
    105     *         class type is an array class)
    106     */
    107    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    108        final ConstantPool cp = cpg.getConstantPool();
    109        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    110        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    111        if (className.startsWith("[")) {
    112            return (ArrayType) Type.getType(className);
    113        }
    114        className = Utility.pathToPackage(className);
    115        return ObjectType.getInstance(className);
    116    }
    117
    118    /**
    119     * @return signature of referenced method/field.
    120     */
    121    public String getSignature(final ConstantPoolGen cpg) {
    122        final ConstantPool cp = cpg.getConstantPool();
    123        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    124        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    125        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
    126    }
    127}