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    package org.apache.commons.jexl2;
018    
019    import java.util.HashMap;
020    import java.util.Map;
021    
022    /**
023     * Wraps a map in a context.
024     * <p>Each entry in the map is considered a variable name, value pair.</p>
025     */
026    public class MapContext implements JexlContext {
027        /**
028         * The wrapped variable map.
029         */
030        protected final Map<String, Object> map;
031    
032        /**
033         * Creates a MapContext on an automatically allocated underlying HashMap.
034         */
035        public MapContext() {
036            this(null);
037        }
038    
039        /**
040         * Creates a MapContext wrapping an existing user provided map.
041         * @param vars the variable map
042         */
043        public MapContext(Map<String, Object> vars) {
044            super();
045            map = vars == null ? new HashMap<String, Object>() : vars;
046        }
047    
048        /** {@inheritDoc} */
049        public boolean has(String name) {
050            return map.containsKey(name);
051        }
052    
053        /** {@inheritDoc} */
054        public Object get(String name) {
055            return map.get(name);
056        }
057    
058        /** {@inheritDoc} */
059        public void set(String name, Object value) {
060            map.put(name, value);
061        }
062    }