package org.hibernate.id.enhanced;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.exception.JDBCExceptionHelper;
import org.hibernate.HibernateException;
/**
* Describes a sequence.
*
* @author Steve Ebersole
*/
public class SequenceStructure implements DatabaseStructure {
private static final Log log = LogFactory.getLog( SequenceStructure.class );
private final String sequenceName;
private final int initialValue;
private final int incrementSize;
private final String sql;
private boolean applyIncrementSizeToSourceValues;
private int accessCounter;
public SequenceStructure(Dialect dialect, String sequenceName, int initialValue, int incrementSize) {
this.sequenceName = sequenceName;
this.initialValue = initialValue;
this.incrementSize = incrementSize;
sql = dialect.getSequenceNextValString( sequenceName );
}
/**
* {@inheritDoc}
*/
public String getName() {
return sequenceName;
}
/**
* {@inheritDoc}
*/
public int getIncrementSize() {
return incrementSize;
}
/**
* {@inheritDoc}
*/
public int getTimesAccessed() {
return accessCounter;
}
/**
* {@inheritDoc}
*/
public AccessCallback buildCallback(final SessionImplementor session) {
return new AccessCallback() {
public long getNextValue() {
accessCounter++;
try {
PreparedStatement st = session.getBatcher().prepareSelectStatement( sql );
try {
ResultSet rs = st.executeQuery();
try {
rs.next();
long result = rs.getLong( 1 );
if ( log.isDebugEnabled() ) {
log.debug("Sequence identifier generated: " + result);
}
return result;
}
finally {
try {
rs.close();
}
catch( Throwable ignore ) {
// intentionally empty
}
}
}
finally {
session.getBatcher().closeStatement( st );
}
}
catch ( SQLException sqle) {
throw JDBCExceptionHelper.convert(
session.getFactory().getSQLExceptionConverter(),
sqle,
"could not get next sequence value",
sql
);
}
}
};
}
/**
* {@inheritDoc}
*/
public void prepare(Optimizer optimizer) {
applyIncrementSizeToSourceValues = optimizer.applyIncrementSizeToSourceValues();
}
/**
* {@inheritDoc}
*/
public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
int sourceIncrementSize = applyIncrementSizeToSourceValues ? incrementSize : 1;
return dialect.getCreateSequenceStrings( sequenceName, initialValue, sourceIncrementSize );
}
/**
* {@inheritDoc}
*/
public String[] sqlDropStrings(Dialect dialect) throws HibernateException {
return dialect.getDropSequenceStrings( sequenceName );
}
}
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