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;
025import org.apache.bcel.classfile.Utility;
026
027/**
028 * Super class for InvokeInstruction and FieldInstruction, since they have some methods in common!
029 *
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     * @param index to constant pool
042     */
043    protected FieldOrMethod(final short opcode, final int index) {
044        super(opcode, index);
045    }
046
047    /**
048     * @return name of the referenced class/interface
049     * @deprecated If the instruction references an array class, this method will return "java.lang.Object". For code
050     *             generated by Java 1.5, this answer is sometimes wrong (e.g., if the "clone()" method is called on an
051     *             array). A better idea is to use the {@link #getReferenceType(ConstantPoolGen)} method, which correctly
052     *             distinguishes between class types and array types.
053     *
054     */
055    @Deprecated
056    public String getClassName(final ConstantPoolGen cpg) {
057        final ConstantPool cp = cpg.getConstantPool();
058        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
059        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
060        if (className.startsWith("[")) {
061            // Turn array classes into java.lang.Object.
062            return "java.lang.Object";
063        }
064        return Utility.pathToPackage(className);
065    }
066
067    /**
068     * @return type of the referenced class/interface
069     * @deprecated If the instruction references an array class, the ObjectType returned will be invalid. Use
070     *             getReferenceType() instead.
071     */
072    @Deprecated
073    public ObjectType getClassType(final ConstantPoolGen cpg) {
074        return ObjectType.getInstance(getClassName(cpg));
075    }
076
077    /**
078     * Gets the ObjectType of the method return or field.
079     *
080     * @return type of the referenced class/interface
081     * @throws ClassGenException when the field is (or method returns) an array,
082     */
083    @Override
084    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
085        final ReferenceType rt = getReferenceType(cpg);
086        if (rt instanceof ObjectType) {
087            return (ObjectType) rt;
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}