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Struts example source code file (DefaultBundleAccessor.java)

This example Struts source code file (DefaultBundleAccessor.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

bundle, bundle, defaultbundleaccessor, hashmap, io, ioexception, ioexception, list, map, net, network, servicereference, set, string, string, url, url, util

The Struts DefaultBundleAccessor.java source code

/*
 * $Id$
 *
 * 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.osgi;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.*;
import java.util.Map.Entry;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;

import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.config.entities.ActionConfig;

/**
 * Helper class that find resources and loads classes from the list of bundles
 */
public class DefaultBundleAccessor implements BundleAccessor {

    private static DefaultBundleAccessor self;
    private static final Logger LOG = LoggerFactory.getLogger(DefaultBundleAccessor.class);

    private BundleContext bundleContext;
    private Map<String, String> packageToBundle = new HashMap();
    private Map<Bundle, Set packagesByBundle = new HashMap>();
    private OsgiHost osgiHost;

    public DefaultBundleAccessor() {
        self = this;
    }

    public static DefaultBundleAccessor getInstance() {
        return self;
    }

    public Object getService(ServiceReference ref) {
        return bundleContext != null ? bundleContext.getService(ref) : null;
    }

    public ServiceReference getServiceReference(String className) {
        return bundleContext != null ? bundleContext.getServiceReference(className) : null;
    }

    public ServiceReference[] getAllServiceReferences(String className) {
        if (bundleContext != null) {
            try {
                return bundleContext.getServiceReferences(className, null);
            } catch (InvalidSyntaxException e) {
                //cannot happen we are passing null as the param
                if (LOG.isErrorEnabled())
                    LOG.error("Invalid syntax for service lookup", e);
            }
        }

        return null;
    }

    public ServiceReference[] getServiceReferences(String className, String params) throws InvalidSyntaxException {
        return bundleContext != null ? bundleContext.getServiceReferences(className, params) : null;
    }

    /**
     *  Add as Bundle -> Package mapping 
     * @param bundle the bundle where the package was loaded from
     * @param packageName the anme of the loaded package
     */
    public void addPackageFromBundle(Bundle bundle, String packageName) {
        this.packageToBundle.put(packageName, bundle.getSymbolicName());
        Set<String> pkgs = packagesByBundle.get(bundle);
        if (pkgs == null) {
            pkgs = new HashSet<String>();
            packagesByBundle.put(bundle, pkgs);
        }
        pkgs.add(packageName);
    }

    public Class<?> loadClass(String className) throws ClassNotFoundException {
        Bundle bundle = getCurrentBundle();
        if (bundle != null) {
            Class cls = bundle.loadClass(className);
            if (LOG.isTraceEnabled())
                LOG.trace("Located class [#0] in bundle [#1]", className, bundle.getSymbolicName());
            return cls;
        }

        throw new ClassNotFoundException("Unable to find class " + className);
    }

    private Bundle getCurrentBundle() {
        ActionContext ctx = ActionContext.getContext();
        String bundleName = (String) ctx.get(CURRENT_BUNDLE_NAME);
        if (bundleName == null) {
            ActionInvocation inv = ctx.getActionInvocation();
            ActionProxy proxy = inv.getProxy();
            ActionConfig actionConfig = proxy.getConfig();
            bundleName = packageToBundle.get(actionConfig.getPackageName());
        }
        if (bundleName != null) {
            return osgiHost.getActiveBundles().get(bundleName);
        }
        return null;
    }

    public List<URL> loadResources(String name) throws IOException {
        return loadResources(name, false);
    }

    public List<URL> loadResources(String name, boolean translate) throws IOException {
        Bundle bundle = getCurrentBundle();
        if (bundle != null) {
            List<URL> resources = new ArrayList();
            Enumeration e = bundle.getResources(name);
            while (e.hasMoreElements()) {
                resources.add(translate ? OsgiUtil.translateBundleURLToJarURL((URL) e.nextElement(), getCurrentBundle()) : (URL) e.nextElement());
            }
            return resources;
        }

        return null;
    }

    public URL loadResourceFromAllBundles(String name) throws IOException {
        for (Map.Entry<String, Bundle> entry : osgiHost.getActiveBundles().entrySet()) {
            Enumeration e = entry.getValue().getResources(name);
            if (e.hasMoreElements()) {
                return (URL) e.nextElement();
            }
        }

        return null;
    }

    public InputStream loadResourceFromAllBundlesAsStream(String name) throws IOException {
        URL url = loadResourceFromAllBundles(name);
        if (url != null) {
            return url.openStream();
        }
        return null;
    }

    public URL loadResource(String name) {
        return loadResource(name, false);
    }

    public URL loadResource(String name, boolean translate) {
        Bundle bundle = getCurrentBundle();
        if (bundle != null) {
            URL url = bundle.getResource(name);
            try {
                return translate ? OsgiUtil.translateBundleURLToJarURL(url, getCurrentBundle()) : url;
            } catch (Exception e) {
                if (LOG.isErrorEnabled()) {
                    LOG.error("Unable to translate bundle URL to jar URL", e);
                }

                return null;
            }
        }

        return null;
    }

    public Set<String> getPackagesByBundle(Bundle bundle) {
        return packagesByBundle.get(bundle);
    }

    public InputStream loadResourceAsStream(String name) throws IOException {
        URL url = loadResource(name);
        if (url != null) {
            return url.openStream();
        }
        return null;
    }

    public void setBundleContext(BundleContext bundleContext) {
        this.bundleContext = bundleContext;
    }

    public void setOsgiHost(OsgiHost osgiHost) {
        this.osgiHost = osgiHost;
    }
}

Other Struts examples (source code examples)

Here is a short list of links related to this Struts DefaultBundleAccessor.java source code file:

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