Unary.java

/*
 * FreeMarker: a tool that allows Java programs to generate HTML
 * output using templates.
 * Copyright (C) 1998-2004 Benjamin Geer
 * Email: beroul@users.sourceforge.net
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 */

package freemarker.template.expression;

/**
 * An interface for unary operators.
 * 
 * @version $Id: Unary.java 987 2004-10-05 10:13:24Z run2000 $
 */
public interface Unary extends Operator {

	/** Indicates a prefix operator */
	public static final int PREFIX = 0;
	/** Indicates a postfix operator */
	public static final int POSTFIX = 1;

	/**
	 * Sets the target for this unary operation.
	 * 
	 * @throws IllegalArgumentException
	 *             the target is of the wrong type for this operator
	 * @throws NullPointerException
	 *             the argument is null
	 */
	public void setTarget(Expression target);

	/**
	 * Determines the operator association of the unary operation.
	 * 
	 * @return <code>PREFIX</code> or <code>POSTFIX</code>.
	 */
	public int getAssociationType();
}