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00025 package org.objectweb.cjdbc.controller.scheduler.raidb0;
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.util.Constants;
00033 import org.objectweb.cjdbc.common.xml.DatabasesXmlTags;
00034 import org.objectweb.cjdbc.controller.requestmanager.RAIDbLevels;
00035 import org.objectweb.cjdbc.controller.scheduler.AbstractScheduler;
00036 import org.objectweb.cjdbc.controller.scheduler.schema.TransactionExclusiveLock;
00037
00038
00039
00040
00041
00042
00043
00044
00045
00046 public class RAIDb0PessimisticTransactionLevelScheduler
00047 extends
00048 AbstractScheduler
00049 {
00050
00051
00052
00053
00054
00055
00056
00057
00058
00059
00060
00061 private long requestId;
00062 private TransactionExclusiveLock lock = new TransactionExclusiveLock();
00063
00064
00065
00066
00067
00068
00069
00070
00071 public RAIDb0PessimisticTransactionLevelScheduler()
00072 {
00073 super(RAIDbLevels.RAIDb0, ParsingGranularities.NO_PARSING);
00074 }
00075
00076
00077
00078
00079
00080
00081
00082
00083
00084
00085
00086 public final void scheduleReadRequest(SelectRequest request)
00087 throws SQLException
00088 {
00089 synchronized (this)
00090 {
00091 request.setId(requestId++);
00092 }
00093 }
00094
00095
00096
00097
00098 public final void readCompletedNotify(SelectRequest request)
00099 {
00100 }
00101
00102
00103
00104
00105
00106
00107
00108
00109 public void scheduleNonSuspendedWriteRequest(AbstractWriteRequest request)
00110 throws SQLException
00111 {
00112 if (request.isCreate())
00113 {
00114 synchronized (this)
00115 {
00116 request.setId(requestId++);
00117 }
00118 return;
00119 }
00120
00121 if (lock.acquire(request))
00122 {
00123 synchronized (this)
00124 {
00125 request.setId(requestId++);
00126 }
00127 if (logger.isDebugEnabled())
00128 logger.debug("Request " + request.getId() + " scheduled for write ("
00129 + getPendingWrites() + " pending writes)");
00130 }
00131 else
00132 {
00133 if (logger.isWarnEnabled())
00134 logger.warn("Request " + request.getId() + " timed out ("
00135 + request.getTimeout() + " s)");
00136 throw new SQLException("Timeout (" + request.getTimeout()
00137 + ") for request: "
00138 + request.getSQLShortForm(Constants.SQL_SHORT_FORM_LENGTH));
00139 }
00140 }
00141
00142
00143
00144
00145 public final synchronized void notifyWriteCompleted(
00146 AbstractWriteRequest request)
00147 {
00148
00149
00150 if (request.isAutoCommit() && (!request.isCreate()))
00151 releaseLock(request.getTransactionId());
00152 }
00153
00154
00155
00156
00157
00158
00159
00160
00161 protected final void commitTransaction(long transactionId)
00162 {
00163 releaseLock(transactionId);
00164 }
00165
00166
00167
00168
00169 protected final void rollbackTransaction(long transactionId)
00170 {
00171 releaseLock(transactionId);
00172 }
00173
00174
00175
00176
00177
00178
00179 private void releaseLock(long transactionId)
00180 {
00181
00182 if (lock.isLocked())
00183 {
00184 if (lock.getLocker() == transactionId)
00185 lock.release();
00186
00187
00188
00189
00190
00191 else if (logger.isDebugEnabled())
00192 logger.debug("Transaction " + transactionId
00193 + " wants to release the lock held by transaction "
00194 + lock.getLocker());
00195 }
00196 else if (logger.isDebugEnabled())
00197 logger.warn("Transaction " + transactionId
00198 + " tries to release a lock that has not been acquired.");
00199 }
00200
00201
00202
00203
00204
00205
00206
00207
00208 public String getXmlImpl()
00209 {
00210 StringBuffer info = new StringBuffer();
00211 info.append("<" + DatabasesXmlTags.ELT_RAIDb0Scheduler + " "
00212 + DatabasesXmlTags.ATT_level + "=\""
00213 + DatabasesXmlTags.VAL_pessimisticTransaction + "\"/>");
00214 return info.toString();
00215 }
00216
00217 }