1 files changed, 158 insertions, 0 deletions
diff --git a/feature-distributed-locking/src/main/java/org/onap/policy/distributed/locking/DistributedLockingFeature.java b/feature-distributed-locking/src/main/java/org/onap/policy/distributed/locking/DistributedLockingFeature.java
new file mode 100644
index 00000000..cc7a7a12
--- /dev/null
+++ b/feature-distributed-locking/src/main/java/org/onap/policy/distributed/locking/DistributedLockingFeature.java
@@ -0,0 +1,158 @@
+/*
+ * ============LICENSE_START=======================================================
+ * feature-distributed-locking
+ * ================================================================================
+ * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.policy.distributed.locking;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.util.UUID;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.onap.policy.common.utils.properties.exception.PropertyException;
+import org.onap.policy.drools.core.lock.LockRequestFuture;
+import org.onap.policy.drools.core.lock.PolicyResourceLockFeatureAPI;
+import org.onap.policy.drools.features.PolicyEngineFeatureAPI;
+import org.onap.policy.drools.persistence.SystemPersistence;
+import org.onap.policy.drools.system.PolicyEngine;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class DistributedLockingFeature implements PolicyEngineFeatureAPI, PolicyResourceLockFeatureAPI {
+	
+	/**
+	 * Logger instance
+	 */
+	private static final Logger logger = LoggerFactory.getLogger(DistributedLockingFeature.class);
+	
+	/**
+	 * Properties Configuration Name
+	 */
+	public static final String CONFIGURATION_PROPERTIES_NAME = "feature-distributed-locking";
+	
+	/**
+	 * Properties for locking feature
+	 */
+	private DistributedLockingProperties lockProps;
+	
+	/**
+	 *ScheduledExecutorService for LockHeartbeat 
+	 */
+	private ScheduledExecutorService scheduledExecutorService;
+	
+	/**
+	 * UUID 
+	 */
+	private static final UUID uuid = UUID.randomUUID();
+	
+	/**
+	 * Config directory
+	 */
+	@Override
+	public int getSequenceNumber() {
+        return 1000;
+	}
+	
+	@Override
+	public Future<Boolean> beforeLock(String resourceId, String owner, Callback callback) {
+		
+		TargetLock tLock = new TargetLock(resourceId, this.uuid, owner, lockProps);
+		
+		return new LockRequestFuture(resourceId, owner, tLock.lock());
+				
+	}
+
+	@Override
+	public Boolean beforeUnlock(String resourceId, String owner) {
+		TargetLock tLock = new TargetLock(resourceId, this.uuid, owner, lockProps);
+		
+		return tLock.unlock();
+	}
+	
+	@Override
+	public Boolean beforeIsLockedBy(String resourceId, String owner) {
+		TargetLock tLock = new TargetLock(resourceId, this.uuid, owner, lockProps);
+		
+		return tLock.isActive();
+	}
+	
+	@Override
+	public Boolean beforeIsLocked(String resourceId) {
+		TargetLock tLock = new TargetLock(resourceId, this.uuid, "dummyOwner", lockProps);
+		
+		return tLock.isLocked();
+	}
+	
+	@Override
+	public boolean afterStart(PolicyEngine engine) {
+
+		try {
+			this.lockProps = new DistributedLockingProperties(SystemPersistence.manager.getProperties(DistributedLockingFeature.CONFIGURATION_PROPERTIES_NAME));
+		} catch (PropertyException e) {
+			logger.error("DistributedLockingFeature feature properies have not been loaded", e);
+			throw new DistributedLockingFeatureException(e);
+		}
+		
+		long heartbeatInterval = this.lockProps.getHeartBeatIntervalProperty();
+		
+		cleanLockTable();
+		Heartbeat heartbeat = new Heartbeat(this.uuid, lockProps);
+		
+		this.scheduledExecutorService = Executors.newScheduledThreadPool(1);
+		this.scheduledExecutorService.scheduleAtFixedRate(heartbeat, heartbeatInterval, heartbeatInterval, TimeUnit.MILLISECONDS);
+		return false;
+	}
+	
+	/**
+	 * This method kills the heartbeat thread and calls refreshLockTable which removes
+	 * any records from the db where the current host is the owner.
+	 */
+	@Override
+	public boolean beforeShutdown(PolicyEngine engine) {
+		scheduledExecutorService.shutdown();
+		cleanLockTable();
+		return false;
+	}
+
+	/**
+	 * This method removes all records owned by the current host from the db.
+	 */
+	private void cleanLockTable() {
+		
+	    try (Connection conn = DriverManager.getConnection(lockProps.getDbUrl(), 
+			lockProps.getDbUser(),
+			lockProps.getDbPwd());
+	    	PreparedStatement statement = conn.prepareStatement("DELETE FROM pooling.locks WHERE host = ? OR expirationTime < ?");
+	    	){
+			
+				statement.setString(1, this.uuid.toString());
+				statement.setLong(2, System.currentTimeMillis());
+				statement.executeUpdate();
+			
+		} catch (SQLException e) {
+			logger.error("error in refreshLockTable()", e);
+		}
+		
+	}
+	
+}