Synchronizer (NetarchiveSuite 7.1 API)

java.lang.Object
- dk.netarkivet.common.distribute.Synchronizer

All Implemented Interfaces:

javax.jms.MessageListener

Direct Known Subclasses:

BitmagArcRepositoryClient, JMSArcRepositoryClient
```
public class Synchronizer
extends Object
implements javax.jms.MessageListener
```
Converts an asynchronous call to a synchronous call. The method sendAndWaitForOneReply() is a blocking call which responds when a reply is received or returns null on timeout.

Constructor Summary

Constructors
Constructor Description

Synchronizer()
Initialise maps containing requests and replies.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`onMessage(javax.jms.Message msg)`	Receives replies from a message queue and triggers the blocked call in sendAndWaitForOneReply().
`NetarkivetMessage`	`sendAndWaitForOneReply(NetarkivetMessage msg, long timeout)`	Sends a message to a message queue and blocks the method invocation until a reply arrives.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Synchronizer
```
public Synchronizer()
```
    Initialise maps containing requests and replies.
- Method Detail
  - onMessage
```
public void onMessage(javax.jms.Message msg)
```
    Receives replies from a message queue and triggers the blocked call in sendAndWaitForOneReply().
    
    Specified by:
    
    onMessage in interface javax.jms.MessageListener
    
    Parameters:
    
    msg - an ObjectMessage containing a NetarkivetMessage.
  - sendAndWaitForOneReply
```
public NetarkivetMessage sendAndWaitForOneReply(NetarkivetMessage msg,
                                                long timeout)
```
    Sends a message to a message queue and blocks the method invocation until a reply arrives. If it times out a null is returned. If a spurious wakeup is received and a timeout is set, the method will carry on waiting for the reply until the total timeout time has been used up. If a spurious wakeup is received and no timeout is set the method will just go back to waiting
    
    Parameters:
    
    msg - the request message
    
    timeout - the timeout in milliseconds (or zero for no timeout)
    
    Returns:
    
    a reply message from the receiver of the request or null if timed out.