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
018package 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 */
035public interface Expression {
036    /**
037     * Evaluates the expression with the variables contained in the
038     * supplied {@link JexlContext}.
039     *
040     * @param context A JexlContext containing variables.
041     * @return The result of this evaluation
042     * @throws JexlException on any error
043     */
044    Object evaluate(JexlContext context);
045
046    /**
047     * Returns the JEXL expression this Expression was created with.
048     *
049     * @return The JEXL expression to be evaluated
050     */
051    String getExpression();
052
053    /**
054     * Returns the JEXL expression by reconstructing it from the parsed tree.
055     * @return the JEXL expression
056     */
057    String dump();
058}