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.jexl3; 019 020import java.util.concurrent.Callable; 021 022/** 023 * Represents a single JEXL expression. 024 * <p> 025 * This simple interface provides access to the underlying textual expression through 026 * {@link JexlExpression#getSourceText()}. 027 * </p> 028 * 029 * <p> 030 * An expression is different than a script - it is simply a reference to 031 * a single expression, not to multiple statements. 032 * This implies 'if','for','while','var' and blocks '{'... '}'are <em>not</em> allowed in expressions. 033 * </p> 034 * <p>Do <em>not</em> create classes that implement this interface; delegate or compose instead.</p> 035 * 036 * @since 1.0 037 */ 038public interface JexlExpression { 039 /** 040 * Evaluates the expression with the variables contained in the 041 * supplied {@link JexlContext}. 042 * 043 * @param context A JexlContext containing variables. 044 * @return The result of this evaluation 045 * @throws JexlException on any error 046 */ 047 Object evaluate(JexlContext context); 048 049 /** 050 * Returns the source text of this expression. 051 * 052 * @return the source text 053 */ 054 String getSourceText(); 055 056 /** 057 * Recreates the source text of this expression from the internal syntactic tree. 058 * 059 * @return the source text 060 */ 061 String getParsedText(); 062 063 /** 064 * Creates a Callable from this expression. 065 * 066 * <p>This allows to submit it to an executor pool and provides support for asynchronous calls.</p> 067 * <p>The interpreter will handle interruption/cancellation gracefully if needed.</p> 068 * 069 * @param context the context 070 * @return the callable 071 * @since 3.1 072 */ 073 Callable<Object> callable(JexlContext context); 074}