/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jface.text.rules;

import org.eclipse.core.runtime.Assert;


/**
 * Standard implementation of <code>IToken</code>.
 */
public class Token implements IToken {

	/** Internal token type: Undefined */
	private static final int T_UNDEFINED= 0;
	/** Internal token type: EOF */
	private static final int T_EOF=	1;
	/** Internal token type: Whitespace */
	private static final int T_WHITESPACE= 2;
	/** Internal token type: Others */
	private static final int T_OTHER=	3;


	/**
	 * Standard token: Undefined.
	 */
	public static final IToken UNDEFINED= new Token(T_UNDEFINED);
	/**
	 * Standard token: End Of File.
	 */
	public static final IToken EOF= new Token(T_EOF);
	/**
	 * Standard token: Whitespace.
	 */
	public static final IToken WHITESPACE= new Token(T_WHITESPACE);

	/**
	 * Standard token: Neither {@link #UNDEFINED}, {@link #WHITESPACE}, nor {@link #EOF}.
	 * @deprecated will be removed
	 */
	@Deprecated
	public static final IToken OTHER= new Token(T_OTHER);

	/** The type of this token */
	private int fType;
	/** The data associated with this token */
	private Object fData;

	/**
	 * Creates a new token according to the given specification which does not
	 * have any data attached to it.
	 *
	 * @param type the type of the token
	 * @since 2.0
	 */
	private Token(int type) {
		fType= type;
		fData= null;
	}

	/**
	 * Creates a new token which represents neither undefined, whitespace, nor EOF.
	 * The newly created token has the given data attached to it.
	 *
	 * @param data the data attached to the newly created token
	 */
	public Token(Object data) {
		fType= T_OTHER;
		fData= data;
	}

	/**
	 * Re-initializes the data of this token. The token may not represent
	 * undefined, whitespace, or EOF.
	 *
	 * @param data to be attached to the token
	 * @since 2.0
	 */
	public void setData(Object data) {
		Assert.isTrue(isOther());
		fData= data;
	}

	@Override
	public Object getData() {
		return fData;
	}

	@Override
	public boolean isOther() {
		return (fType == T_OTHER);
	}

	@Override
	public boolean isEOF() {
		return (fType == T_EOF);
	}

	@Override
	public boolean isWhitespace() {
		return (fType == T_WHITESPACE);
	}

	@Override
	public boolean isUndefined() {
		return (fType == T_UNDEFINED);
	}
}