/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.bcel.generic;

import org.apache.bcel.Const;
import org.apache.bcel.classfile.ConstantCP;
import org.apache.bcel.classfile.ConstantNameAndType;
import org.apache.bcel.classfile.ConstantPool;
import org.apache.bcel.classfile.ConstantUtf8;

Super class for InvokeInstruction and FieldInstruction, since they have
some methods in common!
/**
 * Super class for InvokeInstruction and FieldInstruction, since they have
 * some methods in common!
 *
 */
public abstract class FieldOrMethod extends CPInstruction implements LoadClass {

    
Empty constructor needed for Instruction.readInstruction.
Not to be used otherwise.
/**
     * Empty constructor needed for Instruction.readInstruction.
     * Not to be used otherwise.
     */
    FieldOrMethod() {
        // no init
    }


    
Params:
index – to constant pool/**
     * @param index to constant pool
     */
    protected FieldOrMethod(final short opcode, final int index) {
        super(opcode, index);
    }


    
Returns:
signature of referenced method/field./** @return signature of referenced method/field.
     */
    public String getSignature(final ConstantPoolGen cpg) {
        final ConstantPool cp = cpg.getConstantPool();
        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
    }


    
Returns:
name of referenced method/field./** @return name of referenced method/field.
     */
    public String getName(final ConstantPoolGen cpg) {
        final ConstantPool cp = cpg.getConstantPool();
        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
    }


    
Returns:
name of the referenced class/interface
Deprecated:
If the instruction references an array class, this method will return "java.lang.Object". For code generated by Java 1.5, this answer is sometimes wrong (e.g., if the "clone()" method is called on an array). A better idea is to use the getReferenceType(ConstantPoolGen) method, which correctly distinguishes between class types and array types./**
     * @return name of the referenced class/interface
     * @deprecated If the instruction references an array class,
     *    this method will return "java.lang.Object".
     *    For code generated by Java 1.5, this answer is
     *    sometimes wrong (e.g., if the "clone()" method is
     *    called on an array).  A better idea is to use
     *    the {@link #getReferenceType(ConstantPoolGen)} method, which correctly distinguishes
     *    between class types and array types.
     *
     */
    @Deprecated
    public String getClassName(final ConstantPoolGen cpg) {
        final ConstantPool cp = cpg.getConstantPool();
        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
        if (className.startsWith("[")) {
            // Turn array classes into java.lang.Object.
            return "java.lang.Object";
        }
        return className.replace('/', '.');
    }


    
Returns:
type of the referenced class/interface
Deprecated:
If the instruction references an array class,
   the ObjectType returned will be invalid.  Use
   getReferenceType() instead./** @return type of the referenced class/interface
     * @deprecated If the instruction references an array class,
     *    the ObjectType returned will be invalid.  Use
     *    getReferenceType() instead.
     */
    @Deprecated
    public ObjectType getClassType(final ConstantPoolGen cpg) {
        return ObjectType.getInstance(getClassName(cpg));
    }


    
Gets the reference type representing the class, interface,
or array class referenced by the instruction.
Params:
cpg – the ConstantPoolGen used to create the instruction
Returns:
an ObjectType (if the referenced class type is a class
  or interface), or an ArrayType (if the referenced class
  type is an array class)/**
     * Gets the reference type representing the class, interface,
     * or array class referenced by the instruction.
     * @param cpg the ConstantPoolGen used to create the instruction
     * @return an ObjectType (if the referenced class type is a class
     *   or interface), or an ArrayType (if the referenced class
     *   type is an array class)
     */
    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
        final ConstantPool cp = cpg.getConstantPool();
        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
        if (className.startsWith("[")) {
            return (ArrayType) Type.getType(className);
        }
        className = className.replace('/', '.');
        return ObjectType.getInstance(className);
    }


    
Gets the ObjectType of the method return or field.
Throws:
ClassGenException – when the field is (or method returns) an array,
Returns:
type of the referenced class/interface/**
     * Gets the ObjectType of the method return or field.
     *
     * @return type of the referenced class/interface
     * @throws ClassGenException when the field is (or method returns) an array,
     */
    @Override
    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
        final ReferenceType rt = getReferenceType(cpg);
        if (rt instanceof ObjectType) {
            return (ObjectType) rt;
        }
        throw new ClassGenException(
            rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
    }
}