Struts example source code file (StrutsXmlConfigurationProvider.java)

This example Struts source code file (StrutsXmlConfigurationProvider.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

apache, configuration, file, file, foundation//dtd, io, ioexception, net, network, override, override, servlet, software, string, struts, struts, url, url, util

The Struts StrutsXmlConfigurationProvider.java source code

/*
 * $Id: StrutsXmlConfigurationProvider.java 762875 2009-04-07 17:56:30Z musachy $
 *
 * 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.struts2.config;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.config.providers.XmlConfigurationProvider;
import com.opensymphony.xwork2.inject.ContainerBuilder;
import com.opensymphony.xwork2.inject.Context;
import com.opensymphony.xwork2.inject.Factory;
import com.opensymphony.xwork2.util.location.LocatableProperties;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

/**
 * Override Xwork class so we can use an arbitrary config file
 */
public class StrutsXmlConfigurationProvider extends XmlConfigurationProvider {

    private static final Logger LOG = LoggerFactory.getLogger(StrutsXmlConfigurationProvider.class);
    private File baseDir = null;
    private String filename;
    private String reloadKey;
    private ServletContext servletContext;

    /**
     * Constructs the configuration provider
     *
     * @param errorIfMissing If we should throw an exception if the file can't be found
     */
    public StrutsXmlConfigurationProvider(boolean errorIfMissing) {
        this("struts.xml", errorIfMissing, null);
    }

    /**
     * Constructs the configuration provider
     *
     * @param filename The filename to look for
     * @param errorIfMissing If we should throw an exception if the file can't be found
     * @param ctx Our ServletContext
     */
    public StrutsXmlConfigurationProvider(String filename, boolean errorIfMissing, ServletContext ctx) {
        super(filename, errorIfMissing);
        this.servletContext = ctx;
        this.filename = filename;
        reloadKey = "configurationReload-"+filename;
        Map<String,String> dtdMappings = new HashMap(getDtdMappings());
        dtdMappings.put("-//Apache Software Foundation//DTD Struts Configuration 2.0//EN", "struts-2.0.dtd");
        dtdMappings.put("-//Apache Software Foundation//DTD Struts Configuration 2.1//EN", "struts-2.1.dtd");
        dtdMappings.put("-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN", "struts-2.1.7.dtd");
        setDtdMappings(dtdMappings);
        File file = new File(filename);
        if (file.getParent() != null) {
            this.baseDir = file.getParentFile();
        }
    }
    
    /* (non-Javadoc)
     * @see com.opensymphony.xwork2.config.providers.XmlConfigurationProvider#register(com.opensymphony.xwork2.inject.ContainerBuilder, java.util.Properties)
     */
    @Override
    public void register(ContainerBuilder containerBuilder, LocatableProperties props) throws ConfigurationException {
        if (servletContext != null && !containerBuilder.contains(ServletContext.class)) {
            containerBuilder.factory(ServletContext.class, new Factory<ServletContext>() {
                public ServletContext create(Context context) throws Exception {
                    return servletContext;
                }
            });
        }
        super.register(containerBuilder, props);
    }

    /* (non-Javadoc)
     * @see com.opensymphony.xwork2.config.providers.XmlConfigurationProvider#init(com.opensymphony.xwork2.config.Configuration)
     */
    @Override
    public void loadPackages() {
        ActionContext ctx = ActionContext.getContext();
        ctx.put(reloadKey, Boolean.TRUE);
        super.loadPackages();
    }

    /**
     * Look for the configuration file on the classpath and in the file system
     *
     * @param fileName The file name to retrieve
     * @see com.opensymphony.xwork2.config.providers.XmlConfigurationProvider#getConfigurationUrls
     */
    @Override
    protected Iterator<URL> getConfigurationUrls(String fileName) throws IOException {
        URL url = null;
        if (baseDir != null) {
            url = findInFileSystem(fileName);
            if (url == null) {
                return super.getConfigurationUrls(fileName);
            }
        }
        if (url != null) {
            List<URL> list = new ArrayList();
            list.add(url);
            return list.iterator();
        } else {
            return super.getConfigurationUrls(fileName);
        }
    }

    protected URL findInFileSystem(String fileName) throws IOException {
        URL url = null;
        File file = new File(fileName);
        if (LOG.isDebugEnabled()) {
            LOG.debug("Trying to load file " + file);
        }

        // Trying relative path to original file
        if (!file.exists()) {
            file = new File(baseDir, fileName);
        }
        if (file.exists()) {
            try {
                url = file.toURI().toURL();
            } catch (MalformedURLException e) {
                throw new IOException("Unable to convert "+file+" to a URL");
            }
        }
        return url;
    }

    /**
     * Overrides needs reload to ensure it is only checked once per request
     */
    @Override
    public boolean needsReload() {
        ActionContext ctx = ActionContext.getContext();
        if (ctx != null) {
            return ctx.get(reloadKey) == null && super.needsReload();
        } else {
            return super.needsReload();
        }

    }
    
    public String toString() {
        return ("Struts XML configuration provider ("+filename+")");
    }
}