1 files changed, 173 insertions, 0 deletions
diff --git a/src/main/java/org/onap/music/datastore/CassaLockStore.java b/src/main/java/org/onap/music/datastore/CassaLockStore.java
new file mode 100644
index 00000000..e03a1c07
--- /dev/null
+++ b/src/main/java/org/onap/music/datastore/CassaLockStore.java
@@ -0,0 +1,173 @@
+package org.onap.music.datastore;
+
+import java.util.UUID;
+
+import org.onap.music.eelf.logging.EELFLoggerDelegate;
+import org.onap.music.exceptions.MusicQueryException;
+import org.onap.music.exceptions.MusicServiceException;
+import org.onap.music.main.MusicUtil;
+
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.Row;
+import com.datastax.driver.core.utils.UUIDs;
+
+/*
+ * This is the lock store that is built on top of Cassandra that is used by MUSIC to maintain lock state. 
+ */
+
+public class CassaLockStore {
+	
+	private EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(CassaLockStore.class);
+	
+	public class LockObject{
+		public String lockRef;
+		public String createTime;
+		public String acquireTime;
+		public LockObject(String lockRef, String createTime, 	String acquireTime) {
+			this.lockRef = lockRef;
+			this.acquireTime = acquireTime;
+			this.createTime = createTime;
+			
+		}
+	}
+	CassaDataStore dsHandle;
+	public CassaLockStore() {
+		dsHandle = new CassaDataStore();
+	}
+	
+	public CassaLockStore(CassaDataStore dsHandle) {
+		this.dsHandle=dsHandle;
+	}
+
+    
+	/**
+	 * 
+	 * This method creates a shadow locking table for every main table in Cassandra. This table tracks all information regarding locks. 
+	 * @param keyspace of the application. 
+	 * @param table of the application. 
+	 * @return true if the operation was successful.
+	 * @throws MusicServiceException
+	 * @throws MusicQueryException
+	 */
+	public boolean createLockQueue(String keyspace, String table) throws MusicServiceException, MusicQueryException {
+        logger.info(EELFLoggerDelegate.applicationLogger,
+                "Create lock queue/table for " +  keyspace+"."+table);
+		table = "lockQ_"+table; 
+		String tabQuery = "CREATE TABLE IF NOT EXISTS "+keyspace+"."+table
+				+ " ( key text, lockReference bigint, createTime text, acquireTime text, guard bigint static, PRIMARY KEY ((key), lockReference) ) "
+				+ "WITH CLUSTERING ORDER BY (lockReference ASC);";
+		System.out.println(tabQuery);
+		PreparedQueryObject queryObject = new PreparedQueryObject(); 
+		
+		queryObject.appendQueryString(tabQuery);
+		boolean result;
+		result = dsHandle.executePut(queryObject, "eventual");
+		return result;
+	}
+
+	/**
+	 * This method creates a lock reference for each invocation. The lock references are monotonically increasing timestamps.
+	 * @param keyspace of the locks.
+	 * @param table of the locks.
+	 * @param lockName is the primary key of the lock table
+	 * @return the UUID lock reference.
+	 * @throws MusicServiceException
+	 * @throws MusicQueryException
+	 */
+	public String genLockRefandEnQueue(String keyspace, String table, String lockName) throws MusicServiceException, MusicQueryException {
+        logger.info(EELFLoggerDelegate.applicationLogger,
+                "Create lock reference for " +  keyspace + "." + table + "." + lockName);
+		table = "lockQ_" + table;
+		long lockEpochMillis = System.currentTimeMillis();
+		long lockRef = lockEpochMillis;
+
+		logger.info(EELFLoggerDelegate.applicationLogger,
+				"Created lock reference for " +  keyspace + "." + table + "." + lockName + ":" + lockRef);
+
+        PreparedQueryObject queryObject = new PreparedQueryObject();
+        String defaultQuery = " UPDATE " + keyspace + "." + table + " SET guard=-1 WHERE key=? IF guard = NULL;";
+
+        queryObject.addValue(lockName);
+        queryObject.appendQueryString(defaultQuery);
+        boolean dqResult = dsHandle.executePut(queryObject, "critical");
+//        System.out.println("dqResult: " + dqResult);
+
+
+        queryObject = new PreparedQueryObject();
+		String insQuery = "BEGIN BATCH" +
+                " UPDATE " + keyspace + "." + table + " SET guard=? WHERE key=? IF guard < ?;" +
+                " INSERT INTO " + keyspace + "." + table +
+				"(key, lockReference, createTime, acquireTime) VALUES (?,?,?,?) IF NOT EXISTS; APPLY BATCH;";
+
+        queryObject.addValue(lockRef);
+        queryObject.addValue(lockName);
+        queryObject.addValue(lockRef);
+
+        queryObject.addValue(lockName);
+        queryObject.addValue(lockRef);
+        queryObject.addValue(String.valueOf(lockEpochMillis));
+        queryObject.addValue("0");
+        queryObject.appendQueryString(insQuery);
+        boolean pResult = dsHandle.executePut(queryObject, "critical");
+//        System.out.println("pResult: " + pResult);
+		return String.valueOf(lockRef);
+	}
+	
+	
+	/**
+	 * This method returns the top of lock table/queue for the key. 
+	 * @param keyspace of the application. 
+	 * @param table of the application. 
+	 * @param key is the primary key of the application table
+	 * @return the UUID lock reference.
+	 * @throws MusicServiceException
+	 * @throws MusicQueryException
+	 */
+	public LockObject peekLockQueue(String keyspace, String table, String key) throws MusicServiceException, MusicQueryException{
+        logger.info(EELFLoggerDelegate.applicationLogger,
+                "Peek in lock table for " +  keyspace+"."+table+"."+key);
+		table = "lockQ_"+table; 
+		String selectQuery = "select * from "+keyspace+"."+table+" where key='"+key+"' LIMIT 1;";	
+        PreparedQueryObject queryObject = new PreparedQueryObject();
+        queryObject.appendQueryString(selectQuery);
+		ResultSet results = dsHandle.executeEventualGet(queryObject);
+		Row row = results.one();
+		String lockReference = "" + row.getLong("lockReference");
+		String createTime = row.getString("createTime");
+		String acquireTime = row.getString("acquireTime");
+
+		return new LockObject(lockReference, createTime,acquireTime);
+	}
+	
+	
+	/**
+	 * This method removes the lock ref from the lock table/queue for the key. 
+	 * @param keyspace of the application. 
+	 * @param table of the application. 
+	 * @param key is the primary key of the application table
+	 * @param lockReference the lock reference that needs to be dequeued.
+	 * @throws MusicServiceException
+	 * @throws MusicQueryException
+	 */	
+	public void deQueueLockRef(String keyspace, String table, String key, String lockReference) throws MusicServiceException, MusicQueryException{
+		table = "lockQ_"+table; 
+        PreparedQueryObject queryObject = new PreparedQueryObject();
+        Long lockReferenceL = Long.parseLong(lockReference);
+        String deleteQuery = "delete from "+keyspace+"."+table+" where key='"+key+"' AND lockReference ="+lockReferenceL+" IF EXISTS;";
+        queryObject.appendQueryString(deleteQuery);
+		dsHandle.executePut(queryObject, "critical");	
+	}
+	
+
+	public void updateLockAcquireTime(String keyspace, String table, String key, String lockReference) throws MusicServiceException, MusicQueryException{
+		table = "lockQ_"+table; 
+        PreparedQueryObject queryObject = new PreparedQueryObject();
+        Long lockReferenceL = Long.parseLong(lockReference);
+        String updateQuery = "update "+keyspace+"."+table+" set acquireTime='"+ System.currentTimeMillis()+"' where key='"+key+"' AND lockReference = "+lockReferenceL+" IF EXISTS;";
+        queryObject.appendQueryString(updateQuery);
+		dsHandle.executePut(queryObject, "eventual");	
+
+	}
+	
+
+}