Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.jexl3; import java.util.HashMap; import java.util.Map; /** * Wraps a map in a context. * <p>Each entry in the map is considered a variable name, value pair.</p> */ public class MapContext implements JexlContext { /** * The wrapped variable map. */ private final Map<String, Object> map; /** * Creates a MapContext on an automatically allocated underlying HashMap. */ public MapContext() { this(null); } /** * Creates a MapContext wrapping an existing user provided map. * * @param vars the variable map */ public MapContext(Map<String, Object> vars) { map = vars == null ? new HashMap<String, Object>() : vars; } @Override public boolean has(String name) { return map.containsKey(name); } @Override public Object get(String name) { return map.get(name); } @Override public void set(String name, Object value) { map.put(name, value); } /** * Clears all variables. */ public void clear() { map.clear(); } }