/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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 com.sun.org.apache.bcel.internal.classfile;

import java.io.DataInput;

import java.io.DataOutputStream;

import java.io.IOException;

import com.sun.org.apache.bcel.internal.Const;

/**

 * This class is derived from the abstract {@link Constant}

 * and represents a reference to a (external) class.

 *

 * @see     Constant

 */

public final class ConstantClass extends Constant implements ConstantObject {

    private int nameIndex; // Identical to ConstantString except for the name

    /**

     * Initialize from another object.

     */

    public ConstantClass(final ConstantClass c) {

        this(c.getNameIndex());

    }

    /**

     * Constructs an instance from file data.

     *

     * @param dataInput Input stream

     * @throws IOException if an I/O error occurs reading from the given {@code dataInput}.

     */

    ConstantClass(final DataInput dataInput) throws IOException {

        this(dataInput.readUnsignedShort());

    }

    /**

     * @param nameIndex Name index in constant pool.  Should refer to a

     * ConstantUtf8.

     */

    public ConstantClass(final int nameIndex) {

        super(Const.CONSTANT_Class);

        this.nameIndex = nameIndex;

    }

    /**

     * Called by objects that are traversing the nodes of the tree implicitely

     * defined by the contents of a Java class. I.e., the hierarchy of methods,

     * fields, attributes, etc. spawns a tree of objects.

     *

     * @param v Visitor object

     */

    @Override

    public void accept( final Visitor v ) {

        v.visitConstantClass(this);

    }

    /**

     * Dumps constant class to file stream in binary format.

     *

     * @param file Output file stream

     * @throws IOException if an I/O error occurs writing to the DataOutputStream.

     */

    @Override

    public void dump( final DataOutputStream file ) throws IOException {

        file.writeByte(super.getTag());

        file.writeShort(nameIndex);

    }

    /**

     * @return Name index in constant pool of class name.

     */

    public int getNameIndex() {

        return nameIndex;

    }

    /**

     * @param nameIndex the name index in the constant pool of this Constant Class

     */

    public void setNameIndex( final int nameIndex ) {

        this.nameIndex = nameIndex;

    }

    /** @return String object

     */

    @Override

    public Object getConstantValue( final ConstantPool cp ) {

        final Constant c = cp.getConstant(nameIndex, Const.CONSTANT_Utf8);

        return ((ConstantUtf8) c).getBytes();

    }

    /** @return dereferenced string

     */

    public String getBytes( final ConstantPool cp ) {

        return (String) getConstantValue(cp);

    }

    /**

     * @return String representation.

     */

    @Override

    public String toString() {

        return super.toString() + "(nameIndex = " + nameIndex + ")";

    }

}