/*******************************************************************************
 * Copyright (c) 2000, 2004 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;


/**
 * A token to be returned by a rule.
 */
public interface IToken {

	/**
	 * Return whether this token is undefined.
	 *
	 * @return <code>true</code>if this token is undefined
	 */
	boolean isUndefined();

	/**
	 * Return whether this token represents a whitespace.
	 *
	 * @return <code>true</code>if this token represents a whitespace
	 */
	boolean isWhitespace();

	/**
	 * Return whether this token represents End Of File.
	 *
	 * @return <code>true</code>if this token represents EOF
	 */
	boolean isEOF();

	/**
	 * Return whether this token is neither undefined, nor whitespace, nor EOF.
	 *
	 * @return <code>true</code>if this token is not undefined, not a whitespace, and not EOF
	 */
	boolean isOther();

	/**
	 * Return a data attached to this token. The semantics of this data kept undefined by this interface.
	 *
	 * @return the data attached to this token.
	 */
	Object getData();
}
