ScopeManager.java

/**
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This 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 software 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.exoplatform.commons.scope;

import javax.jcr.RepositoryException;

import org.exoplatform.container.ExoContainer;
import org.exoplatform.container.component.ComponentRequestLifecycle;
import org.exoplatform.services.jcr.RepositoryService;
import org.exoplatform.services.jcr.core.ManageableRepository;
import org.gatein.common.logging.Logger;
import org.gatein.common.logging.LoggerFactory;

/**
 * <p>
 * </p>
 * The scope manager manages the life cycle of a scope value (which means a mere string) associated with the current thread
 * aimed to scope state. The scope manager takes it values from the current repository service name when it is associated with a
 * request on a container containing the repository service.</p>
 *
 * <p>
 * The manager implements the {@link ComponentRequestLifecycle}
 * </p>
 * interface to be aware of the request life cycle.</p>
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 */
public class ScopeManager implements ComponentRequestLifecycle {

    /** The scope thread local. */
    private static final ThreadLocal<String> currentScope = new ThreadLocal<String>();

    /** . */
    private static final Logger log = LoggerFactory.getLogger(ScopeManager.class);

    /**
     * Returns the current scope value or null if no value is associated with the current thread.
     *
     * @return the current scope
     */
    public static String getCurrentScope() {
        return currentScope.get();
    }

    public void startRequest(ExoContainer container) {
        if (currentScope.get() != null) {
            throw new IllegalStateException("Detected scope reentrancy " + currentScope.get());
        }

        //
        RepositoryService repositoryService = (RepositoryService) container.getComponentInstanceOfType(RepositoryService.class);

        //
        String scope = null;
        if (repositoryService != null) {
            try {
                ManageableRepository currentRepository = repositoryService.getCurrentRepository();
                if (currentRepository != null) {
                    scope = currentRepository.getConfiguration().getName();
                }
            } catch (RepositoryException e) {
                log.error("Could not obtain scope value from repository", e);
            }
        }

        //
        if (scope == null) {
            scope = "";
        }

        //
        currentScope.set(scope);
        log.debug("Starting scope request \"" + scope + "\"");
    }

    public void endRequest(ExoContainer container) {
        if (currentScope.get() == null) {
            throw new IllegalStateException("Detected unscoped unscoping ");
        }

        //
        currentScope.set(null);
    }
}