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 */
017package org.apache.commons.jexl2;
018
019import java.util.HashMap;
020import 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 */
026public 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}