NullConstant.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.classfile;

import java.io.IOException;

import org.eclipse.persistence.tools.workbench.utility.classfile.tools.ClassFileDataInputStream;
import org.eclipse.persistence.tools.workbench.utility.io.IndentingPrintWriter;


/**
 * This class models a null class file constant, the first entry
 * in the constant pool.
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public class NullConstant extends Constant {

    /**
     * Construct a "null" class file constant.
     */
    NullConstant(ConstantPool pool, byte tag, ClassFileDataInputStream stream) throws IOException {
        super(pool, tag, stream);
    }

    void initialize(ClassFileDataInputStream stream) throws IOException {
        // do nothing
    }

    public void displayStringOn(IndentingPrintWriter writer) {
        super.displayStringOn(writer);
        writer.println();
    }

    public String description() {
        return "null";
    }

    public Object value() {
        return null;
    }

    public void accept(Visitor visitor) {
        visitor.visit(this);
    }

}