versioningpast.java

pastry的java实现的2.0b版

/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

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********************************************************************************/
package rice.p2p.glacier;

import rice.*;
import rice.p2p.commonapi.*;

/**
 * @(#) VersioningPast.java This interface is exported by a PAST instance that
 * offers access to specific versions of an object.
 *
 * @version $Id: VersioningPast.java 2042 2004-09-03 23:36:52Z ahae $
 * @author Andreas Haeberlen
 */

public interface VersioningPast {

  /**
   * Retrieves the object stored in this instance of Past with the given ID and
   * the specified version. Asynchronously returns a PastContent object as the
   * result to the provided Continuation, or a PastException.
   *
   * @param id the key to be queried @
   * @param version the requested version
   * @param command Command to be performed when the result is received
   */
  public void lookup(Id id, long version, Continuation command);

  /**
   * Retrieves the handles of up to max replicas of the object stored in this
   * instance of Past with the given ID. Asynchronously returns an array of
   * PastContentHandles as the result to the provided Continuation, or a
   * PastException. Each replica handle is obtained from a different primary
   * storage root for the the given key. If max exceeds the replication factor r
   * of this Past instance, only r replicas are returned. This method will
   * return a PastContentHandle[] array containing all of the handles.
   *
   * @param id the key to be queried
   * @param version the requested version
   * @param command Command to be performed when the result is received
   * @param num DESCRIBE THE PARAMETER
   */
  public void lookupHandles(Id id, long version, int num, Continuation command);

  /**
   * Updates the objects stored under the provided keys id to expire no earlier
   * than the provided expiration time. Asyncroniously returns the result to the
   * caller via the provided continuation. The result of this operation is an
   * Object[], which is the same length as the input array of Ids. Each element
   * in the array is either Boolean(true), representing that the refresh
   * succeeded for the cooresponding Id, or an Exception describing why the
   * refresh failed. Specifically, the possible exceptions which can be returned
   * are: ObjectNotFoundException - if no object was found under the given key
   * RefreshFailedException - if the refresh operation failed for any other
   * reason (the getMessage() will describe the failure)
   *
   * @param command Command to be performed when the result is received
   * @param ids DESCRIBE THE PARAMETER
   * @param versions DESCRIBE THE PARAMETER
   * @param expirations DESCRIBE THE PARAMETER
   */
  public void refresh(Id[] ids, long[] versions, long[] expirations, Continuation command);

}