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.HashMap;
021import java.util.Map;
022
023/**
024 * Wraps a map in a context.
025 * <p>Each entry in the map is considered a variable name, value pair.</p>
026 */
027public class MapContext implements JexlContext {
028
029    /**
030     * The wrapped variable map.
031     */
032    private final Map<String, Object> map;
033
034    /**
035     * Creates a MapContext on an automatically allocated underlying HashMap.
036     */
037    public MapContext() {
038        this(null);
039    }
040
041    /**
042     * Creates a MapContext wrapping an existing user provided map.
043     * 
044     * @param vars the variable map
045     */
046    public MapContext(Map<String, Object> vars) {
047        map = vars == null ? new HashMap<String, Object>() : vars;
048    }
049
050    @Override
051    public boolean has(String name) {
052        return map.containsKey(name);
053    }
054
055    @Override
056    public Object get(String name) {
057        return map.get(name);
058    }
059
060    @Override
061    public void set(String name, Object value) {
062        map.put(name, value);
063    }
064
065    /**
066     * Clears all variables.
067     */
068    public void clear() {
069        map.clear();
070    }
071}