/*
 * 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.exoplatform.services.jcr.impl.core.query;

import org.exoplatform.services.jcr.impl.core.SessionDataManager;
import org.exoplatform.services.jcr.impl.core.SessionImpl;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import javax.jcr.Node;
import javax.jcr.RepositoryException;
import javax.jcr.query.InvalidQueryException;
import javax.jcr.query.Query;
import javax.jcr.query.QueryManager;

/**
 * This class implements the {@link QueryManager} interface.
 */
public class QueryManagerImpl implements QueryManager
{

   /**
    * Defines all supported query languages
    */
   private static final String[] SUPPORTED_QUERIES = QueryTreeBuilderRegistry.getSupportedLanguages();

   /**
    * List of all supported query languages
    */
   private static final List<String> SUPPORTED_QUERIES_LIST = Collections.unmodifiableList(Arrays.asList(SUPPORTED_QUERIES));

   /**
    * The <code>Session</code> for this QueryManager.
    */
   private final SessionImpl session;

   /**
    * The <code>ItemManager</code> of for item retrieval in search results
    */
   private final SessionDataManager itemMgr;

   /**
    * The <code>SearchManager</code> holding the search index.
    */
   private final SearchManager searchMgr;

   /**
    * Creates a new <code>QueryManagerImpl</code> for the passed <code>session</code>
    * 
    * @param session
    * @param itemMgr
    * @param searchMgr
    */
   public QueryManagerImpl(SessionImpl session, SessionDataManager itemMgr, SearchManager searchMgr)
   {
      this.session = session;
      this.itemMgr = itemMgr;
      this.searchMgr = searchMgr;
   }

   /**
    * {@inheritDoc}
    */
   public Query createQuery(String statement, String language) throws InvalidQueryException, RepositoryException
   {
      sanityCheck();
      return searchMgr.createQuery(session, itemMgr, statement, language);
   }

   /**
    * {@inheritDoc}
    */
   public Query getQuery(Node node) throws InvalidQueryException, RepositoryException
   {
      sanityCheck();
      return searchMgr.createQuery(session, itemMgr, node);
   }

   /**
    * {@inheritDoc}
    */
   public String[] getSupportedQueryLanguages() throws RepositoryException
   {
      return (String[])SUPPORTED_QUERIES_LIST.toArray(new String[SUPPORTED_QUERIES.length]);
   }

   // ---------------------------< internal >-----------------------------------

   /**
    * Checks if this <code>QueryManagerImpl</code> instance is still usable, otherwise throws a
    * {@link javax.jcr.RepositoryException}.
    * 
    * @throws RepositoryException
    *           if this query manager is not usable anymore, e.g. the corresponding session is
    *           closed.
    */
   private void sanityCheck() throws RepositoryException
   {
      if (!session.isLive() && !SessionImpl.ALLOW_CLOSED_SESSION_USAGE)
      {
         throw new RepositoryException("corresponding session has been closed");
      }
   }
   //------------------------< testing only >----------------------------------

   /**
    * @return the query handler implementation.
    */
   public QueryHandler getQueryHandler() {
       return searchMgr.getHandler();
   }
}