001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.jexl2;
019
020
021 /**
022 * Represents a single JEXL expression.
023 * <p>
024 * This simple interface provides access to the underlying expression through
025 * {@link Expression#getExpression()}.
026 * </p>
027 *
028 * <p>
029 * An expression is different than a script - it is simply a reference of
030 * an expression.
031 * </p>
032 *
033 * @since 1.0
034 * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
035 * @version $Id: Expression.java 884175 2009-11-25 16:23:41Z henrib $
036 */
037 public interface Expression {
038 /**
039 * Evaluates the expression with the variables contained in the
040 * supplied {@link JexlContext}.
041 *
042 * @param context A JexlContext containing variables.
043 * @return The result of this evaluation
044 * @throws JexlException on any error
045 */
046 Object evaluate(JexlContext context);
047
048 /**
049 * Returns the JEXL expression this Expression was created with.
050 *
051 * @return The JEXL expression to be evaluated
052 */
053 String getExpression();
054
055 /**
056 * Returns the JEXL expression by reconstructing it from the parsed tree.
057 * @return the JEXL expression
058 */
059 String dump();
060 }