org.qbroker.jms

Class MongoDBMessenger

java.lang.Object

org.qbroker.net.MongoDBConnector

org.qbroker.jms.MongoDBMessenger

All Implemented Interfaces:

Connector

public class MongoDBMessenger
extends MongoDBConnector

MongoDBMessenger connects to a Mongo database specified by URI and initializes the operations of find and update, etc with JMS Messages on various document collections.

There are four methods, findone(), list(), find() and update() for MongoDB operations. The method of findone() executes a predefined query on the default collection. The rest of methods extract both the collection name and the command from the field of CollectionField and the JSON query and/or the JSON data from the incoming messages. The method of list() is to list all collections with the filter support. The method of find() is used for synchronous requests, whereas update() is for asynchronous persisting request. Therefore, if you what to update collections automatically, please use update(). It will keep retry upon database failures until the message expires.

Author:

yannanlu@yahoo.com

Field Summary

Fields inherited from class org.qbroker.net.MongoDBConnector

ACTION_COUNT, ACTION_FIND, ACTION_FINDANDMODIFY, ACTION_FINDANDREMOVE, ACTION_FINDONE, ACTION_GROUP, ACTION_INSERT, ACTION_LIST, ACTION_MAPREDUCE, ACTION_REMOVE, ACTION_UPDATE, ACTION_UPDATEMULTI, dbName, hostname, isConnected, isSlaveOK, password, port, uri, username

Constructor Summary

Constructors

Constructor and Description
MongoDBMessenger(java.util.Map props)

Method Summary

Modifier and Type	Method and Description
void	find(XQueue xq) It listens to an XQueue for incoming JMS messages and extracts the query JSON statement and data from each message.
void	findone(XQueue xq) It executes the predfined query on the default collection and finds the only one doc.
java.lang.String	getOperation()
static java.lang.StringBuffer	getResult(int type, com.mongodb.DBCursor cursor)
java.lang.StringBuffer	getResult(int type, java.lang.String[] list)
void	list(XQueue xq) It lists all collections in the db
void	update(XQueue xq) It listens to the XQueue for incoming JMS messages and extracts the collection name and JSON data from each message.

Methods inherited from class org.qbroker.net.MongoDBConnector

close, count, find, find, findOne, findOne, getCollection, getCommandID, getURI, insert, isConnected, list, main, parse, reconnect, remove, update, updateMulti

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MongoDBMessenger

public MongoDBMessenger(java.util.Map props)

Method Detail

findone

public void findone(XQueue xq)
             throws NonSQLException,
                    javax.jms.JMSException

It executes the predfined query on the default collection and finds the only one doc. The doc will be put into the body of a new message. The new message will be added to the XQueue as the output.

Throws:

NonSQLException

javax.jms.JMSException

list

public void list(XQueue xq)
          throws NonSQLException,
                 TimeoutException

It lists all collections in the db

Throws:

NonSQLException

TimeoutException

find

public void find(XQueue xq)
          throws NonSQLException,
                 TimeoutException

It listens to an XQueue for incoming JMS messages and extracts the query JSON statement and data from each message. After compiling and setting data on the statement, it executes the JSON statement to query the collection. Based on the result type, the query result can be formatted into the customized content. Or the DBCursor of the query can be put into the message before it is removed from the XQueue. The requester will be able to get the result content or DBCursor out of the message.

Since the query operation relies on the request, this method will intercept the request and processes it. The incoming message is required to be writeable. The method will set a String property of the message specified by the RCField with the return code, indicating the status of the process to fulfill the request. The requester is required to check the value of the property once it gets the message back. If the return code is 0, the query is successful. Otherwise, the message body will not contain the content out of query operation.

If the MaxIdleTime is set to none-zero, it will monitor the idle time and will throw TimeoutException once the idle time exceeds MaxIdleTime. it is up to the caller to handle this exception.

Throws:

NonSQLException

TimeoutException

update

public void update(XQueue xq)
            throws NonSQLException,
                   TimeoutException

It listens to the XQueue for incoming JMS messages and extracts the collection name and JSON data from each message. After the parsing the data, it updates the collection with the query and the data. CollectionField is supposed to contain the name of the collection and the method name separated via the char of '.', similar to the shell. If the collection name contains the char of '.', the method has to be appended to it. If there is no '.' in the name, the default method of update will be assumed.

If the MaxIdleTime is set to none-zero, it will monitor the idle time and will throw TimeoutException once the idle time exceeds MaxIdleTime. It is up to the caller to handle this exception.

The original message will not be modified. If the XQueue has enabled the EXTERNAL_XA bit, it will also acknowledge the messages. It is NOT MT-Safe.

Throws:

NonSQLException

TimeoutException

getResult

public static java.lang.StringBuffer getResult(int type,
                                               com.mongodb.DBCursor cursor)

getResult

public java.lang.StringBuffer getResult(int type,
                                        java.lang.String[] list)
                                 throws com.mongodb.MongoException

Throws:

com.mongodb.MongoException

getOperation

public java.lang.String getOperation()