content: /*
   * Copyright (c) 2009 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.jet.core.expressions;
  
  import org.eclipse.jet.JET2Context;
  import org.eclipse.jet.taglib.JET2TagException;
  
  /**
   * Protocol for embedded expression evaluators
   *
   */
  public interface IEmbeddedExpression {
  	
  	/**
  	 * Return the expression value as a string
  	 * @param context the JET context in which from which variables are to be resolved
  	 * @return a string value
  	 * @throws JET2TagException if the expression cannot be evaluated
  	 */
  	public abstract String evalAsString(JET2Context context) throws JET2TagException;
  	
  	/**
  	 * Test whether the expression contains nothing but text.
  	 * @return <code>true</code> if the expression is text only
  	 */
  	public abstract boolean isText();
  
  }
  