appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/pessimistic/SqlLockManager.java

   1 /*-
   2  * ============LICENSE_START=======================================================
   3  * APPC
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
   6  * Copyright (C) 2017 Amdocs
   7  * ================================================================================
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  * ============LICENSE_END=========================================================
  20  * ECOMP is a trademark and service mark of AT&T Intellectual Property.
  21  */
  22
  23 package org.openecomp.appc.lockmanager.impl.sql.pessimistic;
  24
  25 import java.sql.Connection;
  26 import java.sql.PreparedStatement;
  27 import java.sql.ResultSet;
  28 import java.sql.SQLException;
  29
  30 import org.openecomp.appc.lockmanager.api.LockException;
  31 import org.openecomp.appc.lockmanager.api.LockRuntimeException;
  32 import org.openecomp.appc.lockmanager.impl.sql.JdbcLockManager;
  33 import org.openecomp.appc.lockmanager.impl.sql.Messages;
  34
  35 abstract class SqlLockManager extends JdbcLockManager {
  36
  37         private static final String SQL_LOAD_LOCK_RECORD = "SELECT * FROM %s WHERE RESOURCE_ID=?";
  38         private static final String SQL_INSERT_LOCK_RECORD = "INSERT INTO %s (RESOURCE_ID, OWNER_ID, UPDATED, TIMEOUT) VALUES (?, ?, ?, ?)";
  39         private static final String SQL_UPDATE_LOCK_RECORD = "UPDATE %s SET OWNER_ID=?, UPDATED=?, TIMEOUT=? WHERE RESOURCE_ID=?";
  40         private static final String SQL_CURRENT_TIMESTAMP = "SELECT CURRENT_TIMESTAMP()";
  41
  42         private String sqlLoadLockRecord;
  43         private String sqlInsertLockRecord;
  44         private String sqlUpdateLockRecord;
  45
  46         @Override
  47         public boolean acquireLock(String resource, String owner) throws LockException {
  48                 return acquireLock(resource, owner, 0);
  49         }
  50
  51         @Override
  52         public boolean acquireLock(String resource, String owner, long timeout) throws LockException {
  53                 if(owner == null) {
  54                         throw new LockRuntimeException(Messages.ERR_NULL_LOCK_OWNER.format(resource));
  55                 }
  56                 boolean res = false;
  57                 Connection connection = openDbConnection();
  58                 try {
  59                         enterCriticalSection(connection, resource);
  60                         try {
  61                                 res = lockResource(connection, resource, owner, timeout);
  62                         } finally {
  63                                 leaveCriticalSection(connection, resource);
  64                         }
  65                 } finally {
  66                         closeDbConnection(connection);
  67                 }
  68                 return res;
  69         }
  70
  71         @Override
  72         public void releaseLock(String resource, String owner) throws LockException {
  73                 Connection connection = openDbConnection();
  74                 try {
  75                         enterCriticalSection(connection, resource);
  76                         try {
  77                                 unlockResource(connection, resource, owner);
  78                         } finally {
  79                                 leaveCriticalSection(connection, resource);
  80                         }
  81                 } finally {
  82                         closeDbConnection(connection);
  83                 }
  84         }
  85
  86         @Override
  87         public boolean isLocked(String resource) {
  88                 Connection connection=openDbConnection();
  89                 try {
  90                         LockRecord lockRecord=loadLockRecord(connection,resource);
  91                         if(lockRecord==null){
  92                                 return false;
  93                         }else{
  94                                 if(lockRecord.getOwner()==null){
  95                                         return false;
  96                                 }else if(isLockExpired(lockRecord, connection)){
  97                                         return false;
  98                                 }else{
  99                                         return true;
 100                                 }
 101                         }
 102                 } catch (SQLException e) {
 103                         throw new LockRuntimeException(Messages.EXP_CHECK_LOCK.format(resource));
 104                 }finally {
 105                         closeDbConnection(connection);
 106                 }
 107         }
 108
 109         private boolean lockResource(Connection connection, String resource, String owner, long timeout) throws LockException {
 110                 try {
 111                         boolean res = false;
 112                         LockRecord lockRecord = loadLockRecord(connection, resource);
 113                         if(lockRecord != null) {
 114                                 // lock record already exists
 115                                 String currentOwner = lockRecord.getOwner();
 116                                 if(currentOwner != null) {
 117                                         if(isLockExpired(lockRecord, connection)) {
 118                                                 currentOwner = null;
 119                                         } else if(!owner.equals(currentOwner)) {
 120                                                 throw new LockException(Messages.ERR_LOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 121                                         }
 122                                 }
 123                                 // set new owner on the resource lock record
 124                                 updateLockRecord(connection, resource, owner, timeout);
 125                                 if(currentOwner == null) {
 126                                         // no one locked the resource before
 127                                         res = true;
 128                                 }
 129                         } else {
 130                                 // resource record does not exist in lock table => create new record
 131                                 addLockRecord(connection, resource, owner, timeout);
 132                                 res = true;
 133                         }
 134                         return res;
 135                 } catch(SQLException e) {
 136                         throw new LockRuntimeException(Messages.EXP_LOCK.format(resource), e);
 137                 }
 138         }
 139
 140         private void unlockResource(Connection connection, String resource, String owner) throws LockException {
 141                 try {
 142                         LockRecord lockRecord = loadLockRecord(connection, resource);
 143                         if(lockRecord != null) {
 144                                 // check if expired
 145                                 if(isLockExpired(lockRecord, connection)) {
 146                                         // lock is expired => no lock
 147                                         lockRecord = null;
 148                                 }
 149                         }
 150                         if((lockRecord == null) || (lockRecord.getOwner() == null)) {
 151                                 // resource is not locked
 152                                 throw new LockException(Messages.ERR_UNLOCK_NOT_LOCKED.format(resource));
 153                         }
 154                         String currentOwner = lockRecord.getOwner();
 155                         if(!owner.equals(currentOwner)) {
 156                                 throw new LockException(Messages.ERR_UNLOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 157                         }
 158                         updateLockRecord(connection, resource, null, 0);
 159                         // TODO delete record from table on lock release?
 160 //                      deleteLockRecord(connection, resource);
 161                 } catch(SQLException e) {
 162                         throw new LockRuntimeException(Messages.EXP_UNLOCK.format(resource), e);
 163                 }
 164         }
 165
 166         protected abstract void enterCriticalSection(Connection connection, String resource);
 167
 168         protected abstract void leaveCriticalSection(Connection connection, String resource);
 169
 170         protected LockRecord loadLockRecord(Connection connection, String resource) throws SQLException {
 171                 LockRecord res = null;
 172                 if(sqlLoadLockRecord == null) {
 173                         sqlLoadLockRecord = String.format(SQL_LOAD_LOCK_RECORD, tableName);
 174                 }
 175                 try(PreparedStatement statement = connection.prepareStatement(sqlLoadLockRecord)) {
 176                         statement.setString(1, resource);
 177                         try(ResultSet resultSet = statement.executeQuery()) {
 178                                 if(resultSet.next()) {
 179                                         res = new LockRecord(resource);
 180                                         res.setOwner(resultSet.getString(2));
 181                                         res.setUpdated(resultSet.getLong(3));
 182                                         res.setTimeout(resultSet.getLong(4));
 183                                 }
 184                         }
 185                 }
 186                 return res;
 187         }
 188
 189         protected void addLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 190                 if(sqlInsertLockRecord == null) {
 191                         sqlInsertLockRecord = String.format(SQL_INSERT_LOCK_RECORD, tableName);
 192                 }
 193                 try(PreparedStatement statement = connection.prepareStatement(sqlInsertLockRecord)) {
 194                         statement.setString(1, resource);
 195                         statement.setString(2, owner);
 196                         statement.setLong(3, getCurrentTime(connection));
 197                         statement.setLong(4, timeout);
 198                         statement.executeUpdate();
 199                 }
 200         }
 201
 202         protected void updateLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 203                 if(sqlUpdateLockRecord == null) {
 204                         sqlUpdateLockRecord = String.format(SQL_UPDATE_LOCK_RECORD, tableName);
 205                 }
 206                 try(PreparedStatement statement = connection.prepareStatement(sqlUpdateLockRecord)) {
 207                         statement.setString(1, owner);
 208                         statement.setLong(2, getCurrentTime(connection));
 209                         statement.setLong(3, timeout);
 210                         statement.setString(4, resource);
 211                         statement.executeUpdate();
 212                 }
 213         }
 214
 215 //      protected void deleteLockRecord(Connection connection, String resource) throws SQLException {
 216 //              if(sqlDeleteLockRecord == null) {
 217 //                      sqlDeleteLockRecord = String.format(SQL_DELETE_LOCK_RECORD, tableName);
 218 //              }
 219 //              try(PreparedStatement statement = connection.prepareStatement(sqlDeleteLockRecord)) {
 220 //                      statement.setString(1, resource);
 221 //                      statement.executeUpdate();
 222 //              }
 223 //      }
 224
 225         private boolean isLockExpired(LockRecord lockRecord, Connection connection) throws SQLException {
 226                 long timeout = lockRecord.getTimeout();
 227                 if(timeout == 0) {
 228                         return false;
 229                 }
 230                 long updated = lockRecord.getUpdated();
 231                 long now = getCurrentTime(connection);
 232                 long expiration = updated + timeout;
 233                 return (now > expiration);
 234         }
 235
 236         private long getCurrentTime(Connection connection) throws SQLException {
 237                 long res = -1;
 238                 if(connection != null) {
 239                         try(PreparedStatement statement = connection.prepareStatement(SQL_CURRENT_TIMESTAMP)) {
 240                                 try(ResultSet resultSet = statement.executeQuery()) {
 241                                         if(resultSet.next()) {
 242                                                 res = resultSet.getTimestamp(1).getTime();
 243                                         }
 244                                 }
 245                         }
 246                 }
 247                 if(res == -1) {
 248                         res = System.currentTimeMillis();
 249                 }
 250                 return res;
 251         }
 252 }