Example usage for java.net URLClassLoader URLClassLoader

Introduction

In this page you can find the example usage for java.net URLClassLoader URLClassLoader.

Prototype

public URLClassLoader(URL[] urls)

Source Link

Document

Constructs a new URLClassLoader for the specified URLs using the default delegation parent ClassLoader .

Usage

From source file:org.lockss.plugin.PluginManager.java

protected void processOneRegistryJar(CachedUrl cu, String url, ArchivalUnit au, Map tmpMap) {
    Integer curVersion = Integer.valueOf(cu.getVersion());

    if (cuNodeVersionMap.get(url) == null) {
        cuNodeVersionMap.put(url, Integer.valueOf(-1));
    }//  ww w.j  a  v  a  2  s  . c o  m

    // If we've already visited this CU, skip it unless the current
    // repository node is a different version (older OR newer)
    Integer oldVersion = (Integer) cuNodeVersionMap.get(url);

    if (oldVersion.equals(curVersion)) {
        log.debug2(url + ": JAR repository and map versions are identical.  Skipping...");
        return;
    }

    File blessedJar = null;
    if (cu.getContentSize() == 0) {
        log.debug("Empty plugin jar: " + cu);
        return;
    } else {
        try {
            // Validate and bless the JAR file from the CU.
            blessedJar = jarValidator.getBlessedJar(cu);
            log.debug2("Plugin jar: " + cu.getUrl() + " -> " + blessedJar);
        } catch (IOException ex) {
            log.error("Error processing jar file: " + url, ex);
            return;
        } catch (JarValidator.JarValidationException ex) {
            log.error("CachedUrl did not validate: " + cu, ex);
            return;
        }
    }

    // Update the cuNodeVersion map now that we have the blessed Jar.
    cuNodeVersionMap.put(url, curVersion);

    if (blessedJar != null) {
        // Get the list of plugins to load from this jar.
        List loadPlugins = null;
        try {
            loadPlugins = getJarPluginClasses(blessedJar);
        } catch (IOException ex) {
            log.error("Error while getting list of plugins for " + blessedJar);
            return; // skip this CU.

        }
        log.debug2("Blessed jar: " + blessedJar + ", plugins: " + loadPlugins);

        // Although this -should- never happen, it's possible.
        if (loadPlugins.size() == 0) {
            log.warning("Jar " + blessedJar + " does not contain any plugins.  Skipping...");
            return; // skip this CU.
        }

        // Load the plugin classes
        ClassLoader pluginLoader = null;
        URL blessedUrl;
        try {
            blessedUrl = blessedJar.toURL();
            URL[] urls = new URL[] { blessedUrl };
            pluginLoader = preferLoadablePlugin ? new LoadablePluginClassLoader(urls)
                    : new URLClassLoader(urls);
        } catch (MalformedURLException ex) {
            log.error("Malformed URL exception attempting to create " + "classloader for plugin JAR "
                    + blessedJar);
            return; // skip this CU.
        }

        String pluginName = null;

        for (Iterator pluginIter = loadPlugins.iterator(); pluginIter.hasNext();) {
            pluginName = (String) pluginIter.next();
            String key = pluginKeyFromName(pluginName);

            Plugin plugin;
            PluginInfo info;
            try {
                info = retrievePlugin(pluginName, pluginLoader);
                if (info == null) {
                    log.warning("Probable plugin packaging error: plugin " + pluginName + " not found in "
                            + cu.getUrl());
                    continue;
                } else {
                    info.setCuUrl(url);
                    info.setRegistryAu(au);
                    List urls = info.getResourceUrls();
                    if (urls != null && !urls.isEmpty()) {
                        String jar = urls.get(0).toString();
                        if (jar != null) {
                            // If the blessed jar path is a substring of the jar:
                            // url from which the actual plugin resource or class
                            // was loaded, then it is a loadable plugin.
                            boolean isLoadable = jar.indexOf(blessedUrl.getFile()) > 0;
                            info.setIsOnLoadablePath(isLoadable);
                        }
                    }
                    plugin = info.getPlugin();
                }
            } catch (Exception ex) {
                log.error(String.format("Unable to load plugin %s", pluginName), ex);
                continue;
            }

            PluginVersion version = null;

            try {
                version = new PluginVersion(plugin.getVersion());
                info.setVersion(version);
            } catch (IllegalArgumentException ex) {
                // Don't let this runtime exception stop the daemon.  Skip the plugin.
                log.error(String.format("Skipping plugin %s: %s", pluginName, ex.getMessage()));
                // must stop plugin to enable it to be collected
                plugin.stopPlugin();
                return;
            }

            if (pluginMap.containsKey(key)) {
                // Plugin already exists in the global plugin map.
                // Replace it with a new version if one is available.
                log.debug2("Plugin " + key + " is already in global pluginMap.");
                Plugin otherPlugin = getPlugin(key);
                PluginVersion otherVer = new PluginVersion(otherPlugin.getVersion());
                if (version.toLong() > otherVer.toLong()) {
                    if (log.isDebug2()) {
                        log.debug2("Existing plugin " + plugin.getPluginId() + ": Newer version " + version
                                + " found.");
                    }
                    tmpMap.put(key, info);
                } else {
                    if (log.isDebug2()) {
                        log.debug2("Existing plugin " + plugin.getPluginId() + ": No newer version found.");
                    }
                    // must stop plugin to enable it to be collected
                    plugin.stopPlugin();
                }
            } else if (!tmpMap.containsKey(key)) {
                // Plugin doesn't yet exist in the temporary map, add it.
                tmpMap.put(key, info);

                if (log.isDebug2()) {
                    log.debug2("Plugin " + plugin.getPluginId() + ": No previous version in temp map.");
                }
            } else {
                // Plugin already exists in the temporary map, use whichever
                // version is higher.
                PluginVersion otherVer = ((PluginInfo) tmpMap.get(key)).getVersion();

                if (version.toLong() > otherVer.toLong()) {
                    if (log.isDebug2()) {
                        log.debug2("Plugin " + plugin.getPluginId() + ": version " + version
                                + " is newer than version " + otherVer + " already in temp map, overwriting.");
                    }
                    // Overwrite old key in temp map
                    tmpMap.put(key, info);
                } else {
                    // must stop plugin to enable it to be collected
                    plugin.stopPlugin();
                }
            }
        }
    }
}