Added Sequence Generator and a Factory Delegate utility for Mongo

Author: Ryan Colobong

sipXcommons/src/main/java/org/sipfoundry/commons/mongo/MongoDelegateFactory.java

@@ -0,0 +1,28 @@
+package org.sipfoundry.commons.mongo;
+
+import org.springframework.dao.DataAccessException;
+import org.springframework.data.mongodb.MongoDbFactory;
+
+import com.mongodb.DB;
+
+public class MongoDelegateFactory implements MongoDbFactory {
+
+    private MongoDbFactory m_delegateFactory;
+    private String m_dbName;
+    
+    public MongoDelegateFactory(MongoDbFactory delegateFactory, String dbName) {
+        this.m_delegateFactory = delegateFactory;
+        this.m_dbName = dbName;
+    }
+
+    @Override
+    public DB getDb() throws DataAccessException {
+        return getDb(m_dbName);
+    }
+
+    @Override
+    public DB getDb(String dbName) throws DataAccessException {
+        return m_delegateFactory.getDb(dbName);
+    }
+    
+}

sipXcommons/src/main/java/org/sipfoundry/commons/mongo/MongoSequenceCounter.java

@@ -0,0 +1,83 @@
+package org.sipfoundry.commons.mongo;
+
+import org.apache.commons.lang.StringUtils;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBCollection;
+
+public class MongoSequenceCounter {
+	
+	private static final String COUNTER_COLLECTION_NAME = "counter";
+	private static final String COUNTER_KEY_NAME = "sequence";
+	
+	private MongoSpringTemplate m_dbTemplate;
+	private String m_counterCollectionName;
+	
+	public MongoSequenceCounter() {
+		
+	}
+	
+	public MongoSequenceCounter(MongoSpringTemplate dbTemplate) {
+		this(dbTemplate, COUNTER_COLLECTION_NAME);
+	}
+	
+	public MongoSequenceCounter(MongoSpringTemplate dbTemplate, String collectionName) {
+		this.m_dbTemplate = dbTemplate;
+		this.m_counterCollectionName = collectionName;
+	}
+	
+	public long getCurrentSequence(String key) {
+		Assert.notNull(m_dbTemplate, "MongoTemplate must not be null");
+		
+		BasicDBObject result = (BasicDBObject)getCounterCollection().findOne(
+					new BasicDBObject(MongoConstants.ID, key));
+		if(result != null) {
+			return result.getLong(COUNTER_KEY_NAME);
+		}
+		
+		return 0;
+	}
+	
+	public long getNextSequence(String key) {
+		Assert.notNull(m_dbTemplate, "MongoTemplate must not be null");
+		
+		//Use automic increment operation to prevent race condition
+		//during multiple calls
+		BasicDBObject updateQuery = new BasicDBObject("$inc"
+				, new BasicDBObject(COUNTER_KEY_NAME, 1));
+		
+		//Return the modified/incremented object.
+		BasicDBObject result = (BasicDBObject)getCounterCollection().findAndModify(
+					new BasicDBObject(MongoConstants.ID, key),
+					null, null, false, updateQuery, true, true
+				);
+		return result.getLong(COUNTER_KEY_NAME);
+	}
+	
+	
+	private DBCollection getCounterCollection() {
+		return m_dbTemplate.getDb().getCollection(getCounterCollectionName());
+	}
+	
+	public MongoSpringTemplate getDbTemplate() {
+		return m_dbTemplate;
+	}
+
+	public void setDbTemplate(MongoSpringTemplate dbTemplate) {
+		this.m_dbTemplate = dbTemplate;
+	}
+
+	public String getCounterCollectionName() {
+		if(StringUtils.isBlank(m_counterCollectionName)) {
+			m_counterCollectionName = COUNTER_COLLECTION_NAME;
+		}
+		
+		return m_counterCollectionName;
+	}
+
+	public void setCounterCollectionName(String counterCollectionName) {
+		this.m_counterCollectionName = counterCollectionName;
+	}
+	
+}