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  * ONAP : APPC
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
   6  * ================================================================================
   7  * Copyright (C) 2017 Amdocs
   8  * =============================================================================
   9  * Licensed under the Apache License, Version 2.0 (the "License");
  10  * you may not use this file except in compliance with the License.
  11  * You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  * Unless required by applicable law or agreed to in writing, software
  16  * distributed under the License is distributed on an "AS IS" BASIS,
  17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  * See the License for the specific language governing permissions and
  19  * limitations under the License.
  20  *
  21  * ECOMP is a trademark and service mark of AT&T Intellectual Property.
  22  * ============LICENSE_END=========================================================
  23  */
  24
  25 package org.openecomp.appc.lockmanager.impl.sql.pessimistic;
  26
  27 import java.sql.Connection;
  28 import java.sql.PreparedStatement;
  29 import java.sql.ResultSet;
  30 import java.sql.SQLException;
  31
  32 import org.openecomp.appc.lockmanager.api.LockException;
  33 import org.openecomp.appc.lockmanager.api.LockRuntimeException;
  34 import org.openecomp.appc.lockmanager.impl.sql.JdbcLockManager;
  35 import org.openecomp.appc.lockmanager.impl.sql.Messages;
  36
  37 abstract class SqlLockManager extends JdbcLockManager {
  38
  39         private static final String SQL_LOAD_LOCK_RECORD = "SELECT * FROM %s WHERE RESOURCE_ID=?";
  40         private static final String SQL_INSERT_LOCK_RECORD = "INSERT INTO %s (RESOURCE_ID, OWNER_ID, UPDATED, TIMEOUT) VALUES (?, ?, ?, ?)";
  41         private static final String SQL_UPDATE_LOCK_RECORD = "UPDATE %s SET OWNER_ID=?, UPDATED=?, TIMEOUT=? WHERE RESOURCE_ID=?";
  42         private static final String SQL_CURRENT_TIMESTAMP = "SELECT CURRENT_TIMESTAMP()";
  43
  44         private String sqlLoadLockRecord;
  45         private String sqlInsertLockRecord;
  46         private String sqlUpdateLockRecord;
  47
  48         @Override
  49         public boolean acquireLock(String resource, String owner) throws LockException {
  50                 return acquireLock(resource, owner, 0);
  51         }
  52
  53         @Override
  54         public boolean acquireLock(String resource, String owner, long timeout) throws LockException {
  55                 if(owner == null) {
  56                         throw new LockRuntimeException(Messages.ERR_NULL_LOCK_OWNER.format(resource));
  57                 }
  58                 boolean res = false;
  59                 Connection connection = openDbConnection();
  60                 try {
  61                         enterCriticalSection(connection, resource);
  62                         try {
  63                                 res = lockResource(connection, resource, owner, timeout);
  64                         } finally {
  65                                 leaveCriticalSection(connection, resource);
  66                         }
  67                 } finally {
  68                         closeDbConnection(connection);
  69                 }
  70                 return res;
  71         }
  72
  73         @Override
  74         public void releaseLock(String resource, String owner) throws LockException {
  75                 Connection connection = openDbConnection();
  76                 try {
  77                         enterCriticalSection(connection, resource);
  78                         try {
  79                                 unlockResource(connection, resource, owner);
  80                         } finally {
  81                                 leaveCriticalSection(connection, resource);
  82                         }
  83                 } finally {
  84                         closeDbConnection(connection);
  85                 }
  86         }
  87
  88         @Override
  89         public boolean isLocked(String resource) {
  90                 Connection connection=openDbConnection();
  91                 try {
  92                         LockRecord lockRecord=loadLockRecord(connection,resource);
  93                         if(lockRecord==null){
  94                                 return false;
  95                         }else{
  96                                 if(lockRecord.getOwner()==null){
  97                                         return false;
  98                                 }else if(isLockExpired(lockRecord, connection)){
  99                                         return false;
 100                                 }else{
 101                                         return true;
 102                                 }
 103                         }
 104                 } catch (SQLException e) {
 105                         throw new LockRuntimeException(Messages.EXP_CHECK_LOCK.format(resource));
 106                 }finally {
 107                         closeDbConnection(connection);
 108                 }
 109         }
 110
 111         private boolean lockResource(Connection connection, String resource, String owner, long timeout) throws LockException {
 112                 try {
 113                         boolean res = false;
 114                         LockRecord lockRecord = loadLockRecord(connection, resource);
 115                         if(lockRecord != null) {
 116                                 // lock record already exists
 117                                 String currentOwner = lockRecord.getOwner();
 118                                 if(currentOwner != null) {
 119                                         if(isLockExpired(lockRecord, connection)) {
 120                                                 currentOwner = null;
 121                                         } else if(!owner.equals(currentOwner)) {
 122                                                 throw new LockException(Messages.ERR_LOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 123                                         }
 124                                 }
 125                                 // set new owner on the resource lock record
 126                                 updateLockRecord(connection, resource, owner, timeout);
 127                                 if(currentOwner == null) {
 128                                         // no one locked the resource before
 129                                         res = true;
 130                                 }
 131                         } else {
 132                                 // resource record does not exist in lock table => create new record
 133                                 addLockRecord(connection, resource, owner, timeout);
 134                                 res = true;
 135                         }
 136                         return res;
 137                 } catch(SQLException e) {
 138                         throw new LockRuntimeException(Messages.EXP_LOCK.format(resource), e);
 139                 }
 140         }
 141
 142         private void unlockResource(Connection connection, String resource, String owner) throws LockException {
 143                 try {
 144                         LockRecord lockRecord = loadLockRecord(connection, resource);
 145                         if(lockRecord != null) {
 146                                 // check if expired
 147                                 if(isLockExpired(lockRecord, connection)) {
 148                                         // lock is expired => no lock
 149                                         lockRecord = null;
 150                                 }
 151                         }
 152                         if((lockRecord == null) || (lockRecord.getOwner() == null)) {
 153                                 // resource is not locked
 154                                 throw new LockException(Messages.ERR_UNLOCK_NOT_LOCKED.format(resource));
 155                         }
 156                         String currentOwner = lockRecord.getOwner();
 157                         if(!owner.equals(currentOwner)) {
 158                                 throw new LockException(Messages.ERR_UNLOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 159                         }
 160                         updateLockRecord(connection, resource, null, 0);
 161                         // TODO delete record from table on lock release?
 162 //                      deleteLockRecord(connection, resource);
 163                 } catch(SQLException e) {
 164                         throw new LockRuntimeException(Messages.EXP_UNLOCK.format(resource), e);
 165                 }
 166         }
 167
 168         protected abstract void enterCriticalSection(Connection connection, String resource);
 169
 170         protected abstract void leaveCriticalSection(Connection connection, String resource);
 171
 172         protected LockRecord loadLockRecord(Connection connection, String resource) throws SQLException {
 173                 LockRecord res = null;
 174                 if(sqlLoadLockRecord == null) {
 175                         sqlLoadLockRecord = String.format(SQL_LOAD_LOCK_RECORD, tableName);
 176                 }
 177                 try(PreparedStatement statement = connection.prepareStatement(sqlLoadLockRecord)) {
 178                         statement.setString(1, resource);
 179                         try(ResultSet resultSet = statement.executeQuery()) {
 180                                 if(resultSet.next()) {
 181                                         res = new LockRecord(resource);
 182                                         res.setOwner(resultSet.getString(2));
 183                                         res.setUpdated(resultSet.getLong(3));
 184                                         res.setTimeout(resultSet.getLong(4));
 185                                 }
 186                         }
 187                 }
 188                 return res;
 189         }
 190
 191         protected void addLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 192                 if(sqlInsertLockRecord == null) {
 193                         sqlInsertLockRecord = String.format(SQL_INSERT_LOCK_RECORD, tableName);
 194                 }
 195                 try(PreparedStatement statement = connection.prepareStatement(sqlInsertLockRecord)) {
 196                         statement.setString(1, resource);
 197                         statement.setString(2, owner);
 198                         statement.setLong(3, getCurrentTime(connection));
 199                         statement.setLong(4, timeout);
 200                         statement.executeUpdate();
 201                 }
 202         }
 203
 204         protected void updateLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 205                 if(sqlUpdateLockRecord == null) {
 206                         sqlUpdateLockRecord = String.format(SQL_UPDATE_LOCK_RECORD, tableName);
 207                 }
 208                 try(PreparedStatement statement = connection.prepareStatement(sqlUpdateLockRecord)) {
 209                         statement.setString(1, owner);
 210                         statement.setLong(2, getCurrentTime(connection));
 211                         statement.setLong(3, timeout);
 212                         statement.setString(4, resource);
 213                         statement.executeUpdate();
 214                 }
 215         }
 216
 217 //      protected void deleteLockRecord(Connection connection, String resource) throws SQLException {
 218 //              if(sqlDeleteLockRecord == null) {
 219 //                      sqlDeleteLockRecord = String.format(SQL_DELETE_LOCK_RECORD, tableName);
 220 //              }
 221 //              try(PreparedStatement statement = connection.prepareStatement(sqlDeleteLockRecord)) {
 222 //                      statement.setString(1, resource);
 223 //                      statement.executeUpdate();
 224 //              }
 225 //      }
 226
 227         private boolean isLockExpired(LockRecord lockRecord, Connection connection) throws SQLException {
 228                 long timeout = lockRecord.getTimeout();
 229                 if(timeout == 0) {
 230                         return false;
 231                 }
 232                 long updated = lockRecord.getUpdated();
 233                 long now = getCurrentTime(connection);
 234                 long expiration = updated + timeout;
 235                 return (now > expiration);
 236         }
 237
 238         private long getCurrentTime(Connection connection) throws SQLException {
 239                 long res = -1;
 240                 if(connection != null) {
 241                         try(PreparedStatement statement = connection.prepareStatement(SQL_CURRENT_TIMESTAMP)) {
 242                                 try(ResultSet resultSet = statement.executeQuery()) {
 243                                         if(resultSet.next()) {
 244                                                 res = resultSet.getTimestamp(1).getTime();
 245                                         }
 246                                 }
 247                         }
 248                 }
 249                 if(res == -1) {
 250                         res = System.currentTimeMillis();
 251                 }
 252                 return res;
 253         }
 254 }