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.scxml2.env;
018
019import java.io.Serializable;
020import java.util.AbstractMap;
021import java.util.HashSet;
022import java.util.Set;
023
024import org.apache.commons.scxml2.Context;
025
026/**
027 * A map that will back the effective {@link Context} for an {@link org.apache.commons.scxml2.Evaluator} execution.
028 * The effective context enables the chaining of contexts all the way from the current state node to the root.
029 */
030public final class EffectiveContextMap extends AbstractMap<String, Object> implements Serializable {
031
032    private static final long serialVersionUID = 1L;
033
034    /** The {@link org.apache.commons.scxml2.Context} for the current state. */
035    private final Context leaf;
036
037    /** Constructor. */
038    public EffectiveContextMap(final Context ctx) {
039        super();
040        this.leaf = ctx;
041    }
042
043    /**
044     * {@inheritDoc}
045     */
046    @Override
047    public Set<Entry<String, Object>> entrySet() {
048        Set<Entry<String, Object>> entrySet = new HashSet<Entry<String, Object>>();
049        Context current = leaf;
050        while (current != null) {
051            entrySet.addAll(current.getVars().entrySet());
052            current = current.getParent();
053        }
054        return entrySet;
055    }
056
057    /**
058     * {@inheritDoc}
059     */
060    @Override
061    public Object put(final String key, final Object value) {
062        Object old = leaf.get(key);
063        if (leaf.has(key)) {
064            leaf.set(key, value);
065        } else {
066            leaf.setLocal(key, value);
067        }
068        return old;
069    }
070
071    /**
072     * {@inheritDoc}
073     */
074    @Override
075    public Object get(final Object key) {
076        if (key != null) {
077            Context current = leaf;
078            while (current != null) {
079                if (current.getVars().containsKey(key.toString())) {
080                    return current.getVars().get(key);
081                }
082                current = current.getParent();
083            }
084        }
085        return null;
086    }
087}