org.hibernate.dialect.DerbyDialect Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*
*/
package org.hibernate.dialect;
import java.lang.reflect.Method;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.dialect.function.AnsiTrimFunction;
import org.hibernate.dialect.function.DerbyConcatFunction;
import org.hibernate.id.TableHiLoGenerator;
import org.hibernate.sql.CaseFragment;
import org.hibernate.sql.DerbyCaseFragment;
import org.hibernate.util.ReflectHelper;
/**
* Hibernate Dialect for Cloudscape 10 - aka Derby. This implements both an
* override for the identity column generator as well as for the case statement
* issue documented at:
* http://www.jroller.com/comments/kenlars99/Weblog/cloudscape_soon_to_be_derby
*
* @author Simon Johnston
*/
public class DerbyDialect extends DB2Dialect {
private static final Logger log = LoggerFactory.getLogger( DerbyDialect.class );
private int driverVersionMajor;
private int driverVersionMinor;
public DerbyDialect() {
super();
registerFunction( "concat", new DerbyConcatFunction() );
registerFunction( "trim", new AnsiTrimFunction() );
determineDriverVersion();
}
/*package*/ void determineDriverVersion() {
try {
// locate the derby sysinfo class and query its version info
final Class sysinfoClass = ReflectHelper.classForName( "org.apache.derby.tools.sysinfo", this.getClass() );
final Method majorVersionGetter = sysinfoClass.getMethod( "getMajorVersion", ReflectHelper.NO_PARAM_SIGNATURE );
final Method minorVersionGetter = sysinfoClass.getMethod( "getMinorVersion", ReflectHelper.NO_PARAM_SIGNATURE );
driverVersionMajor = ( (Integer) majorVersionGetter.invoke( null, ReflectHelper.NO_PARAMS ) ).intValue();
driverVersionMinor = ( (Integer) minorVersionGetter.invoke( null, ReflectHelper.NO_PARAMS ) ).intValue();
}
catch ( Exception e ) {
log.warn( "Unable to load/access derby driver class sysinfo to check versions : " + e );
driverVersionMajor = -1;
driverVersionMinor = -1;
}
}
/*package*/ boolean isTenPointFiveReleaseOrNewer() {
return driverVersionMajor > 10 || ( driverVersionMajor == 10 && driverVersionMinor >= 5 );
}
public String getCrossJoinSeparator() {
return ", ";
}
// /**
// * This is different in Cloudscape to DB2.
// */
// public String getIdentityColumnString() {
// return "not null generated always as identity"; //$NON-NLS-1
// }
/**
* Return the case statement modified for Cloudscape.
*/
public CaseFragment createCaseFragment() {
return new DerbyCaseFragment();
}
public boolean dropConstraints() {
return true;
}
// public Class getNativeIdentifierGeneratorClass() {
// return TableHiLoGenerator.class;
// }
public boolean supportsSequences() {
return false;
}
public boolean supportsLimit() {
return isTenPointFiveReleaseOrNewer();
}
//HHH-4531
public boolean supportsCommentOn() {
return false;
}
public boolean supportsLimitOffset() {
return isTenPointFiveReleaseOrNewer();
}
public String getForUpdateString() {
return " for update with rs";
}
public String getWriteLockString(int timeout) {
return " for update with rs";
}
public String getReadLockString(int timeout) {
return " for read only with rs";
}
/**
* {@inheritDoc}
*
* From Derby 10.5 Docs:
*
* Query
* [ORDER BY clause]
* [result offset clause]
* [fetch first clause]
* [FOR UPDATE clause]
* [WITH {RR|RS|CS|UR}]
*
*/
public String getLimitString(String query, final int offset, final int limit) {
StringBuffer sb = new StringBuffer(query.length() + 50);
final String normalizedSelect = query.toLowerCase().trim();
final int forUpdateIndex = normalizedSelect.lastIndexOf( "for update") ;
if ( hasForUpdateClause( forUpdateIndex ) ) {
sb.append( query.substring( 0, forUpdateIndex-1 ) );
}
else if ( hasWithClause( normalizedSelect ) ) {
sb.append( query.substring( 0, getWithIndex( query ) - 1 ) );
}
else {
sb.append( query );
}
if ( offset == 0 ) {
sb.append( " fetch first " );
}
else {
sb.append( " offset " ).append( offset ).append( " rows fetch next " );
}
sb.append( limit ).append( " rows only" );
if ( hasForUpdateClause( forUpdateIndex ) ) {
sb.append(' ');
sb.append( query.substring( forUpdateIndex ) );
}
else if ( hasWithClause( normalizedSelect ) ) {
sb.append( ' ' ).append( query.substring( getWithIndex( query ) ) );
}
return sb.toString();
}
public boolean supportsVariableLimit() {
// we bind the limit and offset values directly into the sql...
return false;
}
private boolean hasForUpdateClause(int forUpdateIndex) {
return forUpdateIndex >= 0;
}
private boolean hasWithClause(String normalizedSelect){
return normalizedSelect.startsWith( "with ", normalizedSelect.length()-7 );
}
private int getWithIndex(String querySelect) {
int i = querySelect.lastIndexOf( "with " );
if ( i < 0 ) {
i = querySelect.lastIndexOf( "WITH " );
}
return i;
}
public String getQuerySequencesString() {
return null ;
}
// Overridden informational metadata ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
public boolean supportsLobValueChangePropogation() {
return false;
}
}