/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed 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.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!
 * 
 * @version $Id: FieldOrMethod.java 386056 2006-03-15 11:31:56Z tcurdt $
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 */
public abstract class FieldOrMethod extends CPInstruction implements LoadClass {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * Empty constructor needed for the Class.newInstance() statement in
	 * Instruction.readInstruction(). Not to be used otherwise.
	 */
	FieldOrMethod() {
	}

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

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

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

	/**
	 * @return name of the referenced class/interface
	 */
	public String getClassName(ConstantPoolGen cpg) {
		ConstantPool cp = cpg.getConstantPool();
		ConstantCP cmr = (ConstantCP) cp.getConstant(index);
		String className = cp.getConstantString(cmr.getClassIndex(),
				org.apache.bcel.Constants.CONSTANT_Class);
		if (className.startsWith("[")) {
			// Turn array classes into java.lang.Object.
			return "java.lang.Object";
		}
		return className.replace('/', '.');
	}

	/**
	 * @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(ConstantPoolGen cpg) {
		return new ObjectType(getClassName(cpg));
	}

	/**
	 * Return 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(ConstantPoolGen cpg) {
		ConstantPool cp = cpg.getConstantPool();
		ConstantCP cmr = (ConstantCP) cp.getConstant(index);
		String className = cp.getConstantString(cmr.getClassIndex(),
				org.apache.bcel.Constants.CONSTANT_Class);
		if (className.startsWith("[")) {
			return (ArrayType) Type.getType(className);
		} else {
			className = className.replace('/', '.');
			return new ObjectType(className);
		}
	}

	/**
	 * @return type of the referenced class/interface
	 */
	@Override
	public ObjectType getLoadClassType(ConstantPoolGen cpg) {
		return getClassType(cpg);
	}
}
