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.jxpath.servlet;
019
020import java.util.Enumeration;
021import java.util.HashSet;
022
023import javax.servlet.ServletContext;
024
025import org.apache.commons.jxpath.DynamicPropertyHandler;
026
027/**
028 * Implementation of the {@link DynamicPropertyHandler} interface that provides access to attributes of a {@link ServletContext}.
029 */
030public class ServletContextHandler implements DynamicPropertyHandler {
031
032    private static final int DEFAULT_PROPERTY_COUNT = 16;
033
034    /**
035     * Constructs a new instance.
036     */
037    public ServletContextHandler() {
038        // empty
039    }
040
041    /**
042     * Collect the property names from bean, storing in set.
043     *
044     * @param set  destination
045     * @param bean to read
046     */
047    protected void collectPropertyNames(final HashSet<String> set, Object bean) {
048        if (bean instanceof HttpSessionAndServletContext) {
049            bean = ((HttpSessionAndServletContext) bean).getServletContext();
050        }
051        final Enumeration<String> e = ((ServletContext) bean).getAttributeNames();
052        while (e.hasMoreElements()) {
053            set.add(e.nextElement());
054        }
055    }
056
057    @Override
058    public Object getProperty(final Object context, final String property) {
059        return ((ServletContext) context).getAttribute(property);
060    }
061
062    @Override
063    public String[] getPropertyNames(final Object context) {
064        final HashSet<String> set = new HashSet<>(DEFAULT_PROPERTY_COUNT);
065        collectPropertyNames(set, context);
066        return set.toArray(new String[set.size()]);
067    }
068
069    @Override
070    public void setProperty(final Object context, final String property, final Object value) {
071        ((ServletContext) context).setAttribute(property, value);
072    }
073}