    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.generic;
    020
    021import org.apache.bcel.Const;
    022import org.apache.bcel.classfile.ConstantCP;
    023import org.apache.bcel.classfile.ConstantNameAndType;
    024import org.apache.bcel.classfile.ConstantPool;
    025import org.apache.bcel.classfile.ConstantUtf8;
    026import org.apache.bcel.classfile.Utility;
    027
    028/**
    029 * Super class for InvokeInstruction and FieldInstruction, since they have some methods in common!
    030 */
    031public abstract class FieldOrMethod extends CPInstruction implements LoadClass {
    032
    033    /**
    034     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    035     */
    036    FieldOrMethod() {
    037        // no init
    038    }
    039
    040    /**
    041     * Constructs a FieldOrMethod.
    042     *
    043     * @param opcode the opcode.
    044     * @param index to constant pool.
    045     */
    046    protected FieldOrMethod(final short opcode, final int index) {
    047        super(opcode, index);
    048    }
    049
    050    /**
    051     * Gets the name of the referenced class/interface.
    052     *
    053     * @param cpg the constant pool generator.
    054     * @return name of the referenced class/interface.
    055     * @deprecated If the instruction references an array class, this method will return "java.lang.Object". For code
    056     *             generated by Java 1.5, this answer is sometimes wrong (for example, if the "clone()" method is called on an
    057     *             array). A better idea is to use the {@link #getReferenceType(ConstantPoolGen)} method, which correctly
    058     *             distinguishes between class types and array types.
    059     */
    060    @Deprecated
    061    public String getClassName(final ConstantPoolGen cpg) {
    062        final ConstantPool cp = cpg.getConstantPool();
    063        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    064        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    065        if (className.startsWith("[")) {
    066            // Turn array classes into java.lang.Object.
    067            return "java.lang.Object";
    068        }
    069        return Utility.pathToPackage(className);
    070    }
    071
    072    /**
    073     * Gets the type of the referenced class/interface.
    074     *
    075     * @param cpg the constant pool generator.
    076     * @return type of the referenced class/interface.
    077     * @deprecated If the instruction references an array class, the ObjectType returned will be invalid. Use
    078     *             getReferenceType() instead.
    079     */
    080    @Deprecated
    081    public ObjectType getClassType(final ConstantPoolGen cpg) {
    082        return ObjectType.getInstance(getClassName(cpg));
    083    }
    084
    085    /**
    086     * Gets the ObjectType of the method return or field.
    087     *
    088     * @param cpg the constant pool generator.
    089     * @return type of the referenced class/interface.
    090     * @throws ClassGenException when the field is (or method returns) an array.
    091     */
    092    @Override
    093    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
    094        final ReferenceType rt = getReferenceType(cpg);
    095        if (rt instanceof ObjectType) {
    096            return (ObjectType) rt;
    097        }
    098        if (rt instanceof ArrayType) {
    099            return Type.OBJECT;
    100        }
    101        throw new ClassGenException(rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
    102    }
    103
    104    /**
    105     * Gets the name of referenced method or field.
    106     *
    107     * @param cpg the constant pool generator.
    108     * @return name of referenced method/field.
    109     */
    110    public String getName(final ConstantPoolGen cpg) {
    111        final ConstantPool cp = cpg.getConstantPool();
    112        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    113        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    114        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
    115    }
    116
    117    /**
    118     * Gets the reference type representing the class, interface, or array class referenced by the instruction.
    119     *
    120     * @param cpg the ConstantPoolGen used to create the instruction.
    121     * @return an ObjectType (if the referenced class type is a class or interface), or an ArrayType (if the referenced
    122     *         class type is an array class)
    123     */
    124    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
    125        final ConstantPool cp = cpg.getConstantPool();
    126        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    127        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
    128        if (className.startsWith("[")) {
    129            return (ArrayType) Type.getType(className);
    130        }
    131        className = Utility.pathToPackage(className);
    132        return ObjectType.getInstance(className);
    133    }
    134
    135    /**
    136     * Gets the signature of referenced method or field.
    137     *
    138     * @param cpg the constant pool generator.
    139     * @return signature of referenced method/field.
    140     */
    141    public String getSignature(final ConstantPoolGen cpg) {
    142        final ConstantPool cp = cpg.getConstantPool();
    143        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
    144        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
    145        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
    146    }
    147}