    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    @Deprecated
    053    public String getClassName(final ConstantPoolGen cpg) {
    054        final ConstantPool cp = cpg.getConstantPool();
    055        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    056        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    057        if (className.startsWith("[")) {
    058            // Turn array classes into java.lang.Object.
    059            return "java.lang.Object";
    060        }
    061        return Utility.pathToPackage(className);
    062    }
    063
    064    /**
    065     * @return type of the referenced class/interface
    066     * @deprecated If the instruction references an array class, the ObjectType returned will be invalid. Use
    067     *             getReferenceType() instead.
    068     */
    069    @Deprecated
    070    public ObjectType getClassType(final ConstantPoolGen cpg) {
    071        return ObjectType.getInstance(getClassName(cpg));
    072    }
    073
    074    /**
    075     * Gets the ObjectType of the method return or field.
    076     *
    077     * @return type of the referenced class/interface
    078     * @throws ClassGenException when the field is (or method returns) an array,
    079     */
    080    @Override
    081    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
    082        final ReferenceType rt = getReferenceType(cpg);
    083        if (rt instanceof ObjectType) {
    084            return (ObjectType) rt;
    085        }
    086        if (rt instanceof ArrayType) {
    087            return Type.OBJECT;
    088        }
    089        throw new ClassGenException(rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
    090    }
    091
    092    /**
    093     * @return name of referenced method/field.
    094     */
    095    public String getName(final ConstantPoolGen cpg) {
    096        final ConstantPool cp = cpg.getConstantPool();
    097        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    098        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    099        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
    100    }
    101
    102    /**
    103     * Gets the reference type representing the class, interface, or array class referenced by the instruction.
    104     *
    105     * @param cpg the ConstantPoolGen used to create the instruction
    106     * @return an ObjectType (if the referenced class type is a class or interface), or an ArrayType (if the referenced
    107     *         class type is an array class)
    108     */
    109    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    110        final ConstantPool cp = cpg.getConstantPool();
    111        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    112        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    113        if (className.startsWith("[")) {
    114            return (ArrayType) Type.getType(className);
    115        }
    116        className = Utility.pathToPackage(className);
    117        return ObjectType.getInstance(className);
    118    }
    119
    120    /**
    121     * @return signature of referenced method/field.
    122     */
    123    public String getSignature(final ConstantPoolGen cpg) {
    124        final ConstantPool cp = cpg.getConstantPool();
    125        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    126        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    127        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
    128    }
    129}