SmartContentAPI.java

/*
 *
 * This is a simple Content Management System (CMS)
 * Copyright (C) 2010  Imran M Yousuf (imyousuf@smartitengineering.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.smartitengineering.cms.api.factory;

import com.smartitengineering.cms.api.factory.workspace.WorkspaceAPI;
import com.smartitengineering.cms.api.factory.content.ContentLoader;
import com.smartitengineering.cms.api.factory.event.EventRegistrar;
import com.smartitengineering.cms.api.factory.type.ContentTypeLoader;
import com.smartitengineering.cms.api.type.ContentType;
import com.smartitengineering.util.bean.BeanFactoryRegistrar;
import com.smartitengineering.util.bean.annotations.Aggregator;
import com.smartitengineering.util.bean.annotations.InjectableField;
import java.util.concurrent.Semaphore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The single point of entry to the APIs' of Smart CMS. All other APIs will be
 * avaiable from this class using the getInstance singleton intializer.<p /> For
 * developers wanting to inject to this intializer use {@link SmartContentAPI#CONTEXT_NAME}
 * as the context name to {@link BeanFactoryRegistrar}. Consult the protected
 * members section to find out the beans available for injection and their class
 * and expected name.
 * @author imyousuf
 * @since 0.1
 */
@Aggregator(contextName = SmartContentAPI.CONTEXT_NAME)
public final class SmartContentAPI {

  /**
   * Name of the context to bind all the beans to be injected into this
   * class.
   */
  public static final String CONTEXT_NAME = "com.smartitnengineering.smart-cms";
  private static final Logger LOGGER = LoggerFactory.getLogger(SmartContentAPI.class);
  private static SmartContentAPI api;
  private static final Semaphore MUTEX = new Semaphore(1);

  private SmartContentAPI() {
  }

  /**
   * Retrieves the singleton instance of the API entry point. The API will
   * have all its beans injected before returning itself.
   * @return The API entry point
   */
  public static SmartContentAPI getInstance() {
    if (api == null) {
      try {
        MUTEX.acquire();
      }
      catch (Exception ex) {
        return null;
      }
      try {
        if (api == null) {
          api = new SmartContentAPI();
          if (LOGGER.isInfoEnabled()) {
            StackTraceElement[] stack = Thread.currentThread().getStackTrace();
            final StringBuilder builder = new StringBuilder();
            for (StackTraceElement traceElement : stack) {
              builder.append(traceElement.getClassName()).append(':').append(traceElement.getMethodName()).append(
                  ':').append(traceElement.getLineNumber()).append('\n');
            }
            LOGGER.info(new StringBuilder("Initializing Smart Content API:\n").append(builder.toString()).toString());
          }
          BeanFactoryRegistrar.aggregate(api);
        }
      }
      finally {
        MUTEX.release();
      }
    }
    return api;
  }
  /**
   * The API for loading all DTOs related to {@link ContentType}. Use the name
   * 'apiContentTypeLoader' as the bean's name to be injected to it.
   */
  @InjectableField(beanName = "apiContentTypeLoader")
  protected ContentTypeLoader contentTypeLoader;
  @InjectableField(beanName = "apiContentLoader")
  protected ContentLoader contentLoader;
  @InjectableField(beanName = "apiWorkspaceApi")
  protected WorkspaceAPI workspaceApi;
  @InjectableField(beanName = "apiEventRegistrar")
  protected EventRegistrar eventRegistrar;

  public EventRegistrar getEventRegistrar() {
    return eventRegistrar;
  }

  public ContentTypeLoader getContentTypeLoader() {
    return contentTypeLoader;
  }

  public ContentLoader getContentLoader() {
    return contentLoader;
  }

  public WorkspaceAPI getWorkspaceApi() {
    return workspaceApi;
  }
}