Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.gwt; import org.opencms.db.CmsDriverManager; import org.opencms.file.CmsObject; import org.opencms.file.CmsResource; import org.opencms.main.CmsEvent; import org.opencms.main.CmsException; import org.opencms.main.CmsLog; import org.opencms.main.I_CmsEventListener; import org.opencms.main.OpenCms; import org.opencms.util.CmsCollectionsGenericWrapper; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.net.MalformedURLException; import java.net.URL; import java.text.ParseException; import java.util.List; import org.apache.commons.logging.Log; import com.google.gwt.user.server.rpc.SerializationPolicy; import com.google.gwt.user.server.rpc.SerializationPolicyLoader; /** * This class contains the data that should be cached for a specific service class.<p> * * We cache instances of this class rather than caching instances of {@link CmsGwtService} directly because * its superclass, {@link com.google.gwt.user.server.rpc.RemoteServiceServlet}, does some caching which we can't use because it doesn't * take the distinction between online and offline requests into account. * * @since 8.0.0 * */ public class CmsGwtServiceContext implements I_CmsEventListener { /** The static log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsGwtServiceContext.class); /** The name, which is used for debugging. */ private String m_name; /** The serialization policy path. */ private String m_serializationPolicyPath; /** The offline serialization policy. */ private SerializationPolicy m_serPolicyOffline; /** The online serialization policy. */ private SerializationPolicy m_serPolicyOnline; /** * Creates a new service context object.<p> * * @param name an identifier which is used for debugging */ public CmsGwtServiceContext(String name) { m_name = name; // listen on VFS changes for serialization policies OpenCms.addCmsEventListener(this, new int[] { I_CmsEventListener.EVENT_RESOURCE_AND_PROPERTIES_MODIFIED, I_CmsEventListener.EVENT_RESOURCES_AND_PROPERTIES_MODIFIED, I_CmsEventListener.EVENT_RESOURCE_MODIFIED, I_CmsEventListener.EVENT_RESOURCES_MODIFIED, I_CmsEventListener.EVENT_RESOURCE_DELETED, I_CmsEventListener.EVENT_PUBLISH_PROJECT, I_CmsEventListener.EVENT_CLEAR_CACHES, I_CmsEventListener.EVENT_CLEAR_ONLINE_CACHES, I_CmsEventListener.EVENT_CLEAR_OFFLINE_CACHES }); } /** * @see org.opencms.main.I_CmsEventListener#cmsEvent(org.opencms.main.CmsEvent) */ public void cmsEvent(CmsEvent event) { CmsResource resource = null; List<CmsResource> resources = null; switch (event.getType()) { case I_CmsEventListener.EVENT_RESOURCE_AND_PROPERTIES_MODIFIED: case I_CmsEventListener.EVENT_RESOURCE_MODIFIED: Object change = event.getData().get(I_CmsEventListener.KEY_CHANGE); if ((change != null) && change.equals(new Integer(CmsDriverManager.NOTHING_CHANGED))) { // skip lock & unlock return; } // a resource has been modified in a way that it *IS NOT* necessary also to clear // lists of cached sub-resources where the specified resource might be contained inside. resource = (CmsResource) event.getData().get(I_CmsEventListener.KEY_RESOURCE); uncacheResource(resource); break; case I_CmsEventListener.EVENT_RESOURCES_AND_PROPERTIES_MODIFIED: // a list of resources and all of their properties have been modified resources = CmsCollectionsGenericWrapper.list(event.getData().get(I_CmsEventListener.KEY_RESOURCES)); uncacheResources(resources); break; case I_CmsEventListener.EVENT_RESOURCE_MOVED: case I_CmsEventListener.EVENT_RESOURCE_DELETED: case I_CmsEventListener.EVENT_RESOURCES_MODIFIED: // a list of resources has been modified resources = CmsCollectionsGenericWrapper.list(event.getData().get(I_CmsEventListener.KEY_RESOURCES)); uncacheResources(resources); break; case I_CmsEventListener.EVENT_CLEAR_ONLINE_CACHES: case I_CmsEventListener.EVENT_PUBLISH_PROJECT: m_serPolicyOnline = null; break; case I_CmsEventListener.EVENT_CLEAR_CACHES: m_serPolicyOnline = null; m_serPolicyOffline = null; break; case I_CmsEventListener.EVENT_CLEAR_OFFLINE_CACHES: m_serPolicyOffline = null; break; default: // noop break; } } /** * @see java.lang.Object#toString() */ @Override public String toString() { return super.toString() + "(" + m_name + ")"; } /** * Returns the serialization policy for the service.<p> * * @param cms the current CMS context * @param moduleBaseURL the module's base URL * @param strongName the strong name of the service * * @return the serialization policy for the given service */ protected SerializationPolicy getSerializationPolicy(CmsObject cms, String moduleBaseURL, String strongName) { if (m_serializationPolicyPath == null) { m_serializationPolicyPath = getSerializationPolicyPath(cms, moduleBaseURL, strongName); } return getSerializationPolicy(cms); } /** * Finds the path of the serialization policy file.<p> * * @param cms the current CMS context * @param moduleBaseURL the GWT module's base url * @param strongName the strong name of the service * * @return the serialization policy path */ protected String getSerializationPolicyPath(CmsObject cms, String moduleBaseURL, String strongName) { // locate the serialization policy file in OpenCms String modulePath = null; try { modulePath = new URL(moduleBaseURL).getPath(); } catch (MalformedURLException ex) { // moduleBaseUrl is bad LOG.error(ex.getLocalizedMessage(), ex); return null; } catch (NullPointerException ex) { // moduleBaseUrl is null LOG.error(ex.getLocalizedMessage(), ex); return null; } String serializationPolicyUrl = SerializationPolicyLoader .getSerializationPolicyFileName(modulePath + strongName); return OpenCms.getLinkManager().getRootPath(cms, serializationPolicyUrl); } /** * Returns the serialization policy, using lazy initialization.<p> * * @param cms the current cms context * * @return the serialization policy */ private SerializationPolicy getSerializationPolicy(CmsObject cms) { boolean online = cms.getRequestContext().getCurrentProject().isOnlineProject(); if (online && (m_serPolicyOnline != null)) { return m_serPolicyOnline; } else if (!online && (m_serPolicyOffline != null)) { return m_serPolicyOffline; } SerializationPolicy serializationPolicy = null; // Open the RPC resource file and read its contents InputStream is; try { is = new ByteArrayInputStream(cms.readFile(m_serializationPolicyPath).getContents()); } catch (CmsException ex) { // most likely file not found String message = "ERROR: The serialization policy file '" + m_serializationPolicyPath + "' was not found; did you forget to include it in this deployment?"; LOG.warn(message); LOG.warn(ex.getLocalizedMessage(), ex); return new CmsDummySerializationPolicy(); } // read the policy try { serializationPolicy = SerializationPolicyLoader.loadFromStream(is, null); } catch (ParseException e) { LOG.error("ERROR: Failed to parse the policy file '" + m_serializationPolicyPath + "'", e); } catch (IOException e) { LOG.error("ERROR: Could not read the policy file '" + m_serializationPolicyPath + "'", e); } finally { try { is.close(); } catch (IOException e) { // Ignore this error } } if (online) { m_serPolicyOnline = serializationPolicy; } else { m_serPolicyOffline = serializationPolicy; } return serializationPolicy; } /** * Removes a cached resource from the cache.<p> * * @param resource the resource */ private void uncacheResource(CmsResource resource) { if (resource == null) { return; } if ((m_serializationPolicyPath != null) && resource.getRootPath().equals(m_serializationPolicyPath)) { m_serPolicyOffline = null; } } /** * Removes a bunch of cached resources from the cache.<p> * * @param resources a list of resources * * @see #uncacheResource(CmsResource) */ private void uncacheResources(List<CmsResource> resources) { if (resources == null) { return; } for (int i = 0, n = resources.size(); i < n; i++) { // remove the resource uncacheResource(resources.get(i)); } } }