Moving all files to root directory

Change-Id: Ica5535fd6ec85f350fe1640b42137b49f83f10f0
Signed-off-by: Patrick Brady <pb071s@att.com>

8 files changed, 671 insertions, 0 deletions

diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockManagerInMemoryImpl.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockManagerInMemoryImpl.java
new file mode 100644
index 000000000..309e2790c
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockManagerInMemoryImpl.java
@@ -0,0 +1,130 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.inmemory;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.openecomp.appc.lockmanager.api.LockException;
+import org.openecomp.appc.lockmanager.api.LockManager;
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+
+
+public class LockManagerInMemoryImpl implements LockManager {
+
+    private static LockManagerInMemoryImpl instance = null;
+    private Map<String, LockValue> lockedVNFs;
+
+    private static final EELFLogger debugLogger = EELFManager.getInstance().getDebugLogger();
+
+    private LockManagerInMemoryImpl() {
+        lockedVNFs = new ConcurrentHashMap<>();
+    }
+
+    public static LockManager getLockManager() {
+        if(instance == null) {
+            instance = new LockManagerInMemoryImpl();
+        }
+        return instance;
+    }
+
+    @Override
+    public boolean acquireLock(String resource, String owner) throws LockException {
+        return acquireLock(resource, owner, 0);
+    }
+
+    @Override
+    public boolean acquireLock(String resource, String owner, long timeout) throws LockException {
+        debugLogger.debug("Try to acquire lock on resource " + resource + " with owner " + owner);
+        long now = System.currentTimeMillis();
+        LockValue lockValue = lockedVNFs.get(resource);
+        if (lockValue != null) {
+            if (lockIsMine(lockValue, owner, now) || hasExpired(lockValue, now)) {
+                setExpirationTime(resource, owner, timeout, now);
+                debugLogger.debug("Locked successfully resource " + resource + " with owner " + owner + " for " + timeout + " ms");
+                return hasExpired(lockValue, now);
+            }
+            else {
+                debugLogger.debug("Owner " + owner + " tried to lock resource " + resource + " but it is already locked by owner " + lockValue.getOwner());
+                throw new LockException("Owner " + owner + " tried to lock resource " + resource + " but it is already locked by owner " + lockValue.getOwner());
+            }
+        }
+        else {
+            setExpirationTime(resource, owner, timeout, now);
+            debugLogger.debug("Locked successfully resource " + resource + " with owner " + owner + " for " + timeout + " ms");
+            return true;
+        }
+    }
+
+    @Override
+    public void releaseLock(String resource, String owner) throws LockException {
+        debugLogger.debug("Try to release lock on resource " + resource + " with owner " + owner);
+        long now = System.currentTimeMillis();
+        LockValue lockValue = lockedVNFs.get(resource);
+        if (lockValue != null) {
+            if (!hasExpired(lockValue, now)) {
+                if (isOwner(lockValue, owner)) {
+                    debugLogger.debug("Unlocked successfully resource " + resource + " with owner " + owner);
+                    lockedVNFs.remove(resource);
+                }
+                else {
+                    debugLogger.debug("Unlock failed. Tried to release lock on resource " + resource + " from owner " + owner + " but it is held by a different owner");
+                    throw new LockException("Unlock failed. Tried to release lock on resource " + resource + " from owner " + owner + " but it is held by a different owner");
+                }
+            }
+            else {
+                lockedVNFs.remove(resource);
+                debugLogger.debug("Unlock failed. lock on resource " + resource + " has expired");
+                throw new LockException("Unlock failed. lock on resource " + resource + " has expired");
+            }
+
+        }
+        else {
+            debugLogger.debug("Tried to release lock on resource " + resource + " from owner " + owner + " but there  is not lock on this resource");
+            throw new LockException("Tried to release lock on resource " + resource + " from owner " + owner + " but there  is not lock on this resource");
+        }
+    }
+
+    @Override
+    public boolean isLocked(String resource) {
+        return lockedVNFs.get(resource)!=null?true:false;
+    }
+
+    private boolean lockIsMine(LockValue lockValue, String owner, long now) {
+        return isOwner(lockValue, owner) && !hasExpired(lockValue, now);
+    }
+
+    private boolean isOwner(LockValue lockValue, String owner) {
+        return lockValue.getOwner() != null && lockValue.getOwner().equals(owner);
+    }
+
+    private boolean hasExpired(LockValue lockValue, long now) {
+        return (lockValue.getExpirationTime() != 0 && now > lockValue.getExpirationTime());
+    }
+
+    private void setExpirationTime(String resource, String owner, long timeout, long now) {
+        long expirationTime = timeout == 0 ? 0 : now + timeout;
+        LockValue lockValue = new LockValue(owner, expirationTime);
+        lockedVNFs.put(resource, lockValue);
+    }
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockValue.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockValue.java
new file mode 100644
index 000000000..abdd494d9
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/inmemory/LockValue.java
@@ -0,0 +1,43 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.inmemory;
+
+
+public class LockValue {
+
+    private String owner;
+    private long expirationTime;
+
+    LockValue(String owner, long expirationTime) {
+        this.owner = owner;
+        this.expirationTime = expirationTime;
+    }
+
+    String getOwner() {
+        return owner;
+    }
+
+    long getExpirationTime() {
+        return expirationTime;
+    }
+
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/JdbcLockManager.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/JdbcLockManager.java
new file mode 100644
index 000000000..97a5cc339
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/JdbcLockManager.java
@@ -0,0 +1,51 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql;
+
+import java.sql.Connection;
+
+import org.openecomp.appc.dao.util.JdbcConnectionFactory;
+import org.openecomp.appc.lockmanager.api.LockManager;
+
+public abstract class JdbcLockManager implements LockManager {
+
+    private static final String DEF_TABLE_LOCK_MANAGEMENT = "LOCK_MANAGEMENT";
+
+    private JdbcConnectionFactory connectionFactory;
+    protected String tableName = DEF_TABLE_LOCK_MANAGEMENT;
+
+    public void setConnectionFactory(JdbcConnectionFactory connectionFactory) {
+        this.connectionFactory = connectionFactory;
+    }
+
+    public void setTableName(String tableName) {
+        this.tableName = tableName;
+    }
+
+    protected Connection openDbConnection() {
+        return connectionFactory.openDbConnection();
+    }
+
+    protected void closeDbConnection(Connection connection) {
+        connectionFactory.closeDbConnection(connection);
+    }
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/Messages.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/Messages.java
new file mode 100644
index 000000000..0399726b5
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/Messages.java
@@ -0,0 +1,47 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql;
+
+public enum Messages {
+
+    ERR_NULL_LOCK_OWNER("Cannot acquire lock for resource [%s]: lock owner must be specified"),
+    ERR_LOCK_LOCKED_BY_OTHER("Cannot lock resource [%s] for [%s]: already locked by [%s]"),
+    ERR_UNLOCK_NOT_LOCKED("Error unlocking resource [%s]: resource is not locked"),
+    ERR_UNLOCK_LOCKED_BY_OTHER("Error unlocking resource [%s] by [%s]: resource is locked by [%s]"),
+    EXP_LOCK("Error locking resource [%s]."),
+    EXP_UNLOCK("Error unlocking resource [%s]."),
+    ;
+
+    private String message;
+
+    Messages(String message) {
+        this.message = message;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public String format(Object... s) {
+        return String.format(message, s);
+    }
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/MySqlConnectionFactory.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/MySqlConnectionFactory.java
new file mode 100644
index 000000000..4ccd0c453
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/MySqlConnectionFactory.java
@@ -0,0 +1,34 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql;
+
+import java.sql.DriverManager;
+import java.sql.SQLException;
+
+import org.openecomp.appc.dao.util.DefaultJdbcConnectionFactory;
+
+public class MySqlConnectionFactory extends DefaultJdbcConnectionFactory {
+
+    protected void registedDriver() throws SQLException {
+        DriverManager.registerDriver(new com.mysql.jdbc.Driver());
+    }
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/LockRecord.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/LockRecord.java
new file mode 100644
index 000000000..d66804488
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/LockRecord.java
@@ -0,0 +1,71 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql.optimistic;
+
+class LockRecord {
+
+	private String resource;
+	private String owner;
+	private long updated;
+	private long timeout;
+	private long ver;
+
+	LockRecord(String resource) {
+		this.resource = resource;
+	}
+
+	public String getResource() {
+		return resource;
+	}
+
+	public String getOwner() {
+		return owner;
+	}
+
+	public void setOwner(String owner) {
+		this.owner = owner;
+	}
+
+	public long getUpdated() {
+		return updated;
+	}
+
+	public void setUpdated(long updated) {
+		this.updated = updated;
+	}
+
+	public long getTimeout() {
+		return timeout;
+	}
+
+	public void setTimeout(long timeout) {
+		this.timeout = timeout;
+	}
+
+	public long getVer() {
+		return ver;
+	}
+
+	public void setVer(long ver) {
+		this.ver = ver;
+	}
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/MySqlLockManager.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/MySqlLockManager.java
new file mode 100644
index 000000000..e80133620
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/MySqlLockManager.java
@@ -0,0 +1,32 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql.optimistic;
+
+import java.sql.SQLException;
+
+public class MySqlLockManager extends SqlLockManager {
+
+	@Override
+	protected boolean isDuplicatePkError(SQLException e) {
+		return (e.getErrorCode() == 1062);
+	}
+}
diff --git a/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/SqlLockManager.java b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/SqlLockManager.java
new file mode 100644
index 000000000..52c75d2b2
--- /dev/null
+++ b/appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/optimistic/SqlLockManager.java
@@ -0,0 +1,263 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 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.openecomp.appc.lockmanager.impl.sql.optimistic;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import org.openecomp.appc.lockmanager.api.LockException;
+import org.openecomp.appc.lockmanager.api.LockRuntimeException;
+import org.openecomp.appc.lockmanager.impl.sql.JdbcLockManager;
+import org.openecomp.appc.lockmanager.impl.sql.Messages;
+
+abstract class SqlLockManager extends JdbcLockManager {
+
+	private static final String SQL_LOAD_LOCK_RECORD = "SELECT * FROM %s WHERE RESOURCE_ID=?";
+	private static final String SQL_INSERT_LOCK_RECORD = "INSERT INTO %s (RESOURCE_ID, OWNER_ID, UPDATED, TIMEOUT, VER) VALUES (?, ?, ?, ?, ?)";
+	private static final String SQL_UPDATE_LOCK_RECORD = "UPDATE %s SET OWNER_ID=?, UPDATED=?, TIMEOUT=?, VER=? WHERE RESOURCE_ID=? AND VER=?";
+//	private static final String SQL_DELETE_LOCK_RECORD = "DELETE FROM %s WHERE RESOURCE_ID=? AND VER=?";
+	private static final String SQL_CURRENT_TIMESTAMP = "SELECT CURRENT_TIMESTAMP()";
+
+	private String sqlLoadLockRecord;
+	private String sqlInsertLockRecord;
+	private String sqlUpdateLockRecord;
+//	private String sqlDeleteLockRecord;
+
+	@Override
+	public boolean acquireLock(String resource, String owner) throws LockException {
+		return acquireLock(resource, owner, 0);
+	}
+
+	@Override
+	public boolean acquireLock(String resource, String owner, long timeout) throws LockException {
+		if(owner == null) {
+			throw new LockRuntimeException(Messages.ERR_NULL_LOCK_OWNER.format(resource));
+		}
+		boolean res = false;
+		Connection connection = openDbConnection();
+		try {
+			res = lockResource(connection, resource, owner, timeout);
+		} finally {
+			closeDbConnection(connection);
+		}
+		return res;
+	}
+
+	@Override
+	public void releaseLock(String resource, String owner) throws LockException {
+		Connection connection = openDbConnection();
+		try {
+			unlockResource(connection, resource, owner);
+		} finally {
+			closeDbConnection(connection);
+		}
+	}
+
+	@Override
+	public boolean isLocked(String resource) {
+        Connection connection=openDbConnection();
+		try {
+			LockRecord lockRecord=loadLockRecord(connection,resource);
+			if(lockRecord==null){
+				return false;
+			}else{
+				if(lockRecord.getOwner()==null){
+					return false;
+				}else if(isLockExpired(lockRecord, connection)){
+					return false;
+				}else{
+                    return true;
+                }
+			}
+		} catch (SQLException e) {
+			throw new LockRuntimeException(Messages.EXP_LOCK.format(resource));
+		}finally {
+            closeDbConnection(connection);
+        }
+    }
+
+	private boolean lockResource(Connection connection, String resource, String owner, long timeout) throws LockException {
+		try {
+			boolean res = false;
+			LockRecord lockRecord = loadLockRecord(connection, resource);
+			if(lockRecord != null) {
+				// lock record already exists
+				String currentOwner = lockRecord.getOwner();
+				if(currentOwner != null) {
+					if(isLockExpired(lockRecord, connection)) {
+						currentOwner = null;
+					} else if(!owner.equals(currentOwner)) {
+						throw new LockException(Messages.ERR_LOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
+					}
+				}
+				// set new owner on the resource lock record
+				if(!updateLockRecord(connection, resource, owner, timeout, lockRecord.getVer())) {
+					// try again - maybe same owner updated the record
+					lockResource(connection, resource, owner, timeout);
+				}
+				if(currentOwner == null) {
+					// no one locked the resource before
+					res = true;
+				}
+			} else {
+				// resource record does not exist in lock table => create new record
+				try {
+					addLockRecord(connection, resource, owner, timeout);
+					res = true;
+				} catch(SQLException e) {
+					if(isDuplicatePkError(e)) {
+						// try again - maybe same owner inserted the record
+						lockResource(connection, resource, owner, timeout);
+					} else {
+						throw e;
+					}
+				}
+			}
+			return res;
+		} catch(SQLException e) {
+			throw new LockRuntimeException(Messages.EXP_LOCK.format(resource), e);
+		}
+	}
+
+	protected boolean isDuplicatePkError(SQLException e) {
+		return e.getSQLState().startsWith("23");
+	}
+
+	private void unlockResource(Connection connection, String resource, String owner) throws LockException {
+		try {
+			LockRecord lockRecord = loadLockRecord(connection, resource);
+			if(lockRecord != null) {
+				// check if expired
+				if(isLockExpired(lockRecord, connection)) {
+					// lock is expired => no lock
+					lockRecord = null;
+				}
+			}
+			if((lockRecord == null) || (lockRecord.getOwner() == null)) {
+				// resource is not locked
+				throw new LockException(Messages.ERR_UNLOCK_NOT_LOCKED.format(resource));
+			}
+			String currentOwner = lockRecord.getOwner();
+			if(!owner.equals(currentOwner)) {
+				throw new LockException(Messages.ERR_UNLOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
+            }
+            if (!updateLockRecord(connection, resource, null, 0, lockRecord.getVer())) {
+				unlockResource(connection, resource, owner);
+			}
+			// TODO delete record from table on lock release?
+//			deleteLockRecord(connection, resource, lockRecord.getVer());
+		} catch(SQLException e) {
+			throw new LockRuntimeException(Messages.EXP_UNLOCK.format(resource), e);
+		}
+	}
+
+	protected LockRecord loadLockRecord(Connection connection, String resource) throws SQLException {
+		LockRecord res = null;
+		if(sqlLoadLockRecord == null) {
+			sqlLoadLockRecord = String.format(SQL_LOAD_LOCK_RECORD, tableName);
+		}
+		try(PreparedStatement statement = connection.prepareStatement(sqlLoadLockRecord)) {
+			statement.setString(1, resource);
+			try(ResultSet resultSet = statement.executeQuery()) {
+				if(resultSet.next()) {
+					res = new LockRecord(resource);
+					res.setOwner(resultSet.getString(2));
+					res.setUpdated(resultSet.getLong(3));
+					res.setTimeout(resultSet.getLong(4));
+					res.setVer(resultSet.getLong(5));
+				}
+			}
+		}
+		return res;
+	}
+
+	protected void addLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
+		if(sqlInsertLockRecord == null) {
+			sqlInsertLockRecord = String.format(SQL_INSERT_LOCK_RECORD, tableName);
+		}
+		try(PreparedStatement statement = connection.prepareStatement(sqlInsertLockRecord)) {
+			statement.setString(1, resource);
+			statement.setString(2, owner);
+            statement.setLong(3, getCurrentTime(connection));
+			statement.setLong(4, timeout);
+			statement.setLong(5, 1);
+			statement.executeUpdate();
+		}
+	}
+
+	protected boolean updateLockRecord(Connection connection, String resource, String owner, long timeout, long ver) throws SQLException {
+		if(sqlUpdateLockRecord == null) {
+			sqlUpdateLockRecord = String.format(SQL_UPDATE_LOCK_RECORD, tableName);
+		}
+		try(PreparedStatement statement = connection.prepareStatement(sqlUpdateLockRecord)) {
+			long newVer = (ver >= Long.MAX_VALUE) ? 1 : (ver + 1);
+			statement.setString(1, owner);
+            statement.setLong(2, getCurrentTime(connection));
+			statement.setLong(3, timeout);
+			statement.setLong(4, newVer);
+			statement.setString(5, resource);
+			statement.setLong(6, ver);
+			return (statement.executeUpdate() != 0);
+		}
+	}
+
+//	protected void deleteLockRecord(Connection connection, String resource, long ver) throws SQLException {
+//		if(sqlDeleteLockRecord == null) {
+//			sqlDeleteLockRecord = String.format(SQL_DELETE_LOCK_RECORD, tableName);
+//		}
+//		try(PreparedStatement statement = connection.prepareStatement(sqlDeleteLockRecord)) {
+//			statement.setString(1, resource);
+//			statement.setLong(2, ver);
+//			statement.executeUpdate();
+//		}
+//	}
+
+	private boolean isLockExpired(LockRecord lockRecord, Connection connection) throws SQLException {
+		long timeout = lockRecord.getTimeout();
+		if(timeout == 0) {
+			return false;
+		}
+		long updated = lockRecord.getUpdated();
+        long now = getCurrentTime(connection);
+		long expiration = updated + timeout;
+		return (now > expiration);
+	}
+
+	private long getCurrentTime(Connection connection) throws SQLException {
+		long res = -1;
+		if(connection != null) {
+			try(PreparedStatement statement = connection.prepareStatement(SQL_CURRENT_TIMESTAMP)) {
+				try(ResultSet resultSet = statement.executeQuery()) {
+					if(resultSet.next()) {
+						res = resultSet.getTimestamp(1).getTime();
+					}
+				}
+			}
+		}
+		if(res == -1) {
+			res = System.currentTimeMillis();
+		}
+		return res;
+	}
+}