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00025 package org.objectweb.cjdbc.controller.scheduler.raidb2;
00026
00027 import java.sql.SQLException;
00028
00029 import org.objectweb.cjdbc.common.sql.AbstractWriteRequest;
00030 import org.objectweb.cjdbc.common.sql.ParsingGranularities;
00031 import org.objectweb.cjdbc.common.sql.SelectRequest;
00032 import org.objectweb.cjdbc.common.xml.DatabasesXmlTags;
00033 import org.objectweb.cjdbc.controller.requestmanager.RAIDbLevels;
00034 import org.objectweb.cjdbc.controller.scheduler.AbstractScheduler;
00035 import org.objectweb.cjdbc.controller.scheduler.schema.TransactionExclusiveLock;
00036
00037
00038
00039
00040
00041
00042
00043
00044
00045 public class RAIDb2PessimisticTransactionLevelScheduler
00046 extends AbstractScheduler
00047 {
00048
00049
00050
00051
00052
00053
00054
00055
00056
00057
00058
00059 private long requestId;
00060 private TransactionExclusiveLock lock = new TransactionExclusiveLock();
00061
00062
00063
00064
00065
00066
00067
00068
00069 public RAIDb2PessimisticTransactionLevelScheduler()
00070 {
00071 super(RAIDbLevels.RAIDb2, ParsingGranularities.NO_PARSING);
00072 }
00073
00074
00075
00076
00077
00078
00079
00080
00081
00082
00083
00084 public final void scheduleReadRequest(SelectRequest request)
00085 throws SQLException
00086 {
00087 synchronized (this)
00088 {
00089 request.setId(requestId++);
00090 }
00091 }
00092
00093
00094
00095
00096 public final void readCompletedNotify(SelectRequest request)
00097 {
00098 }
00099
00100
00101
00102
00103
00104
00105 public void scheduleNonSuspendedWriteRequest(AbstractWriteRequest request)
00106 throws SQLException
00107 {
00108 if (request.isCreate())
00109 {
00110 synchronized (this)
00111 {
00112 request.setId(requestId++);
00113 }
00114 return;
00115 }
00116
00117 if (lock.acquire(request))
00118 {
00119 synchronized (this)
00120 {
00121 request.setId(requestId++);
00122 }
00123 if (logger.isDebugEnabled())
00124 logger.debug("Request " + request.getId() + " scheduled for write ("
00125 + getPendingWrites() + " pending writes)");
00126 }
00127 else
00128 {
00129 if (logger.isWarnEnabled())
00130 logger.warn("Request " + request.getId() + " timed out ("
00131 + request.getTimeout() + " s)");
00132 throw new SQLException("Timeout (" + request.getTimeout()
00133 + ") for request: " + request.getId());
00134 }
00135 }
00136
00137
00138
00139
00140 public final synchronized void notifyWriteCompleted(
00141 AbstractWriteRequest request)
00142 {
00143
00144
00145 if (request.isAutoCommit() && (!request.isCreate()))
00146 releaseLock(request.getTransactionId());
00147 }
00148
00149
00150
00151
00152
00153
00154
00155
00156 protected final void commitTransaction(long transactionId)
00157 {
00158 if (lock.isLocked())
00159 releaseLock(transactionId);
00160
00161 }
00162
00163
00164
00165
00166 protected final void rollbackTransaction(long transactionId)
00167 {
00168 if (lock.isLocked())
00169 releaseLock(transactionId);
00170
00171 }
00172
00173
00174
00175
00176
00177
00178 private void releaseLock(long transactionId)
00179 {
00180
00181 if (lock.isLocked())
00182 {
00183 if (lock.getLocker() == transactionId)
00184 lock.release();
00185
00186
00187
00188
00189 else if (logger.isDebugEnabled())
00190 logger.debug("Transaction " + transactionId
00191 + " wants to release the lock held by transaction "
00192 + lock.getLocker());
00193 }
00194 else if (logger.isDebugEnabled())
00195 logger.warn("Transaction " + transactionId
00196 + " tries to release a lock that has not been acquired.");
00197 }
00198
00199
00200
00201
00202
00203
00204
00205
00206 public String getXmlImpl()
00207 {
00208 return "<" + DatabasesXmlTags.ELT_RAIDb2Scheduler + " "
00209 + DatabasesXmlTags.ATT_level + "=\""
00210 + DatabasesXmlTags.VAL_pessimisticTransaction + "\"/>";
00211 }
00212
00213 }