    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 *
    017 */
    018package org.apache.bcel.generic;
    019
    020import org.apache.bcel.Const;
    021import org.apache.bcel.classfile.ConstantCP;
    022import org.apache.bcel.classfile.ConstantNameAndType;
    023import org.apache.bcel.classfile.ConstantPool;
    024import org.apache.bcel.classfile.ConstantUtf8;
    025
    026/**
    027 * Super class for InvokeInstruction and FieldInstruction, since they have
    028 * some methods in common!
    029 *
    030 */
    031public abstract class FieldOrMethod extends CPInstruction implements LoadClass {
    032
    033    /**
    034     * Empty constructor needed for Instruction.readInstruction.
    035     * Not to be used otherwise.
    036     */
    037    FieldOrMethod() {
    038        // no init
    039    }
    040
    041
    042    /**
    043     * @param index to constant pool
    044     */
    045    protected FieldOrMethod(final short opcode, final int index) {
    046        super(opcode, index);
    047    }
    048
    049
    050    /** @return signature of referenced method/field.
    051     */
    052    public String getSignature(final ConstantPoolGen cpg) {
    053        final ConstantPool cp = cpg.getConstantPool();
    054        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    055        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    056        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
    057    }
    058
    059
    060    /** @return name of referenced method/field.
    061     */
    062    public String getName(final ConstantPoolGen cpg) {
    063        final ConstantPool cp = cpg.getConstantPool();
    064        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    065        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    066        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
    067    }
    068
    069
    070    /**
    071     * @return name of the referenced class/interface
    072     * @deprecated If the instruction references an array class,
    073     *    this method will return "java.lang.Object".
    074     *    For code generated by Java 1.5, this answer is
    075     *    sometimes wrong (e.g., if the "clone()" method is
    076     *    called on an array).  A better idea is to use
    077     *    the {@link #getReferenceType(ConstantPoolGen)} method, which correctly distinguishes
    078     *    between class types and array types.
    079     *
    080     */
    081    @Deprecated
    082    public String getClassName(final ConstantPoolGen cpg) {
    083        final ConstantPool cp = cpg.getConstantPool();
    084        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    085        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    086        if (className.startsWith("[")) {
    087            // Turn array classes into java.lang.Object.
    088            return "java.lang.Object";
    089        }
    090        return className.replace('/', '.');
    091    }
    092
    093
    094    /** @return type of the referenced class/interface
    095     * @deprecated If the instruction references an array class,
    096     *    the ObjectType returned will be invalid.  Use
    097     *    getReferenceType() instead.
    098     */
    099    @Deprecated
    100    public ObjectType getClassType(final ConstantPoolGen cpg) {
    101        return ObjectType.getInstance(getClassName(cpg));
    102    }
    103
    104
    105    /**
    106     * Gets the reference type representing the class, interface,
    107     * or array class referenced by the instruction.
    108     * @param cpg the ConstantPoolGen used to create the instruction
    109     * @return an ObjectType (if the referenced class type is a class
    110     *   or interface), or an ArrayType (if the referenced class
    111     *   type is an array class)
    112     */
    113    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    114        final ConstantPool cp = cpg.getConstantPool();
    115        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    116        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    117        if (className.startsWith("[")) {
    118            return (ArrayType) Type.getType(className);
    119        }
    120        className = className.replace('/', '.');
    121        return ObjectType.getInstance(className);
    122    }
    123
    124
    125    /**
    126     * Gets the ObjectType of the method return or field.
    127     *
    128     * @return type of the referenced class/interface
    129     * @throws ClassGenException when the field is (or method returns) an array,
    130     */
    131    @Override
    132    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
    133        final ReferenceType rt = getReferenceType(cpg);
    134        if (rt instanceof ObjectType) {
    135            return (ObjectType) rt;
    136        }
    137        throw new ClassGenException(
    138            rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
    139    }
    140}