Package org.hibernate.dialect

Source Code of org.hibernate.dialect.DerbyDialect

/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. 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 Inc.
*
* 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 java.sql.Types;

import org.jboss.logging.Logger;

import org.hibernate.MappingException;
import org.hibernate.dialect.function.AnsiTrimFunction;
import org.hibernate.dialect.function.DerbyConcatFunction;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.sql.CaseFragment;
import org.hibernate.sql.DerbyCaseFragment;

/**
* 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
*
* @deprecated HHH-6073
*/
@Deprecated
public class DerbyDialect extends DB2Dialect {

    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, DerbyDialect.class.getName());

  private int driverVersionMajor;
  private int driverVersionMinor;

  public DerbyDialect() {
    super();
    if (this.getClass() == DerbyDialect.class) {
      LOG.deprecatedDerbyDialect();
    }
    registerFunction( "concat", new DerbyConcatFunction() );
    registerFunction( "trim", new AnsiTrimFunction() );
        registerColumnType( Types.BLOB, "blob" );
        determineDriverVersion();

        if ( driverVersionMajor > 10 || ( driverVersionMajor == 10 && driverVersionMinor >= 7 ) ) {
            registerColumnType( Types.BOOLEAN, "boolean" );
        }
  }

  @SuppressWarnings({ "UnnecessaryUnboxing" })
  private 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.unableToLoadDerbyDriver( e.getMessage() );
      driverVersionMajor = -1;
      driverVersionMinor = -1;
    }
  }

  private boolean isTenPointFiveReleaseOrNewer() {
    return driverVersionMajor > 10 || ( driverVersionMajor == 10 && driverVersionMinor >= 5 );
  }

  @Override
    public String getCrossJoinSeparator() {
    return ", ";
  }

  /**
   * Return the case statement modified for Cloudscape.
   */
  @Override
    public CaseFragment createCaseFragment() {
    return new DerbyCaseFragment();
  }

  @Override
    public boolean dropConstraints() {
        return true;
  }

  @Override
    public boolean supportsSequences() {
    // technically sequence support was added in 10.6.1.0...
    //
    // The problem though is that I am not exactly sure how to differentiate 10.6.1.0 from any other 10.6.x release.
    //
    // http://db.apache.org/derby/docs/10.0/publishedapi/org/apache/derby/tools/sysinfo.html seems incorrect.  It
    // states that derby's versioning scheme is major.minor.maintenance, but obviously 10.6.1.0 has 4 components
    // to it, not 3.
    //
    // Let alone the fact that it states that versions with the matching major.minor are 'feature
    // compatible' which is clearly not the case here (sequence support is a new feature...)
    return driverVersionMajor > 10 || ( driverVersionMajor == 10 && driverVersionMinor >= 6 );
  }

  @Override
  public String getSequenceNextValString(String sequenceName) {
    if ( supportsSequences() ) {
      return "values next value for " + sequenceName;
    }
    else {
      throw new MappingException( "Derby does not support sequence prior to release 10.6.1.0" );
    }
  }

  @Override
    public boolean supportsLimit() {
    return isTenPointFiveReleaseOrNewer();
  }

  //HHH-4531
  @Override
    public boolean supportsCommentOn() {
    return false;
  }

  @Override
    public boolean supportsLimitOffset() {
    return isTenPointFiveReleaseOrNewer();
  }

   @Override
public String getForUpdateString() {
    return " for update with rs";
   }

  @Override
    public String getWriteLockString(int timeout) {
    return " for update with rs";
  }

  @Override
    public String getReadLockString(int timeout) {
    return " for read only with rs";
  }


  /**
   * {@inheritDoc}
   * <p/>
   * From Derby 10.5 Docs:
   * <pre>
   * Query
   * [ORDER BY clause]
   * [result offset clause]
   * [fetch first clause]
   * [FOR UPDATE clause]
   * [WITH {RR|RS|CS|UR}]
   * </pre>
   */
  @Override
    public String getLimitString(String query, final int offset, final int limit) {
    StringBuilder sb = new StringBuilder(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();
  }

  @Override
    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;
  }

  @Override
    public String getQuerySequencesString() {
     return null ;
  }


  // Overridden informational metadata ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  @Override
    public boolean supportsLobValueChangePropogation() {
    return false;
  }

  @Override
    public boolean supportsUnboundedLobLocatorMaterialization() {
    return false;
  }
}
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