Catalog.java

/**
 *  Copyright 2007-2008 University Of Southern California
 *
 *  Licensed 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 edu.isi.pegasus.planner.catalog;

import java.util.Properties;

/**
 * This interface create a common ancestor for all cataloging
 * interfaces.
 *
 * @author Jens-S. Vöckler
 * @author Yong Zhao
 * @version $Revision$
 */
public interface Catalog{


    /**
     * The default DB Driver properties prefix.
     */
    public static final String DB_ALL_PREFIX = "pegasus.catalog.*.db";


  /**
   * Establishes a link between the implementation and the thing the
   * implementation is build upon. <p>
   * FIXME: The cause for failure is lost without exceptions.
   *
   * @param props contains all necessary data to establish the link.
   * @return true if connected now, or false to indicate a failure.
   */
  public boolean connect( Properties props );

  /**
   * Explicitely free resources before the garbage collection hits.
   */
  public void close();

  /**
   * Predicate to check, if the connection with the catalog's
   * implementation is still active. This helps determining, if it makes
   * sense to call <code>close()</code>.
   *
   * @return true, if the implementation is disassociated, false otherwise.
   * @see #close()
   */
  public boolean isClosed();
}