Package org.hibernate.hql.internal.ast.tree

Source Code of org.hibernate.hql.internal.ast.tree.IndexNode

/*
* 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.hql.internal.ast.tree;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;

import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.QueryException;
import org.hibernate.engine.internal.JoinSequence;
import org.hibernate.engine.spi.QueryParameters;
import org.hibernate.hql.internal.ast.SqlGenerator;
import org.hibernate.hql.internal.ast.util.SessionFactoryHelper;
import org.hibernate.param.ParameterSpecification;
import org.hibernate.persister.collection.QueryableCollection;
import org.hibernate.type.CollectionType;
import org.hibernate.type.Type;
import org.jboss.logging.Logger;
import antlr.RecognitionException;
import antlr.SemanticException;
import antlr.collections.AST;

/**
* Represents the [] operator and provides it's semantics.
*
* @author josh
*/
public class IndexNode extends FromReferenceNode {

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

  public void setScalarColumnText(int i) throws SemanticException {
    throw new UnsupportedOperationException( "An IndexNode cannot generate column text!" );
  }

  @Override
    public void prepareForDot(String propertyName) throws SemanticException {
    FromElement fromElement = getFromElement();
    if ( fromElement == null ) {
      throw new IllegalStateException( "No FROM element for index operator!" );
    }
    QueryableCollection queryableCollection = fromElement.getQueryableCollection();
    if ( queryableCollection != null && !queryableCollection.isOneToMany() ) {

      FromReferenceNode collectionNode = ( FromReferenceNode ) getFirstChild();
      String path = collectionNode.getPath() + "[]." + propertyName;
            LOG.debugf("Creating join for many-to-many elements for %s", path);
      FromElementFactory factory = new FromElementFactory( fromElement.getFromClause(), fromElement, path );
      // This will add the new from element to the origin.
      FromElement elementJoin = factory.createElementJoin( queryableCollection );
      setFromElement( elementJoin );
    }
  }

  public void resolveIndex(AST parent) throws SemanticException {
    throw new UnsupportedOperationException();
  }

  public void resolve(boolean generateJoin, boolean implicitJoin, String classAlias, AST parent)
  throws SemanticException {
    if ( isResolved() ) {
      return;
    }
    FromReferenceNode collectionNode = ( FromReferenceNode ) getFirstChild();
    SessionFactoryHelper sessionFactoryHelper = getSessionFactoryHelper();
    collectionNode.resolveIndex( this );    // Fully resolve the map reference, create implicit joins.

    Type type = collectionNode.getDataType();
    if ( !type.isCollectionType() ) {
      throw new SemanticException( "The [] operator cannot be applied to type " + type.toString() );
    }
    String collectionRole = ( ( CollectionType ) type ).getRole();
    QueryableCollection queryableCollection = sessionFactoryHelper.requireQueryableCollection( collectionRole );
    if ( !queryableCollection.hasIndex() ) {
      throw new QueryException( "unindexed fromElement before []: " + collectionNode.getPath() );
    }

    // Generate the inner join -- The elements need to be joined to the collection they are in.
    FromElement fromElement = collectionNode.getFromElement();
    String elementTable = fromElement.getTableAlias();
    FromClause fromClause = fromElement.getFromClause();
    String path = collectionNode.getPath();

    FromElement elem = fromClause.findCollectionJoin( path );
    if ( elem == null ) {
      FromElementFactory factory = new FromElementFactory( fromClause, fromElement, path );
      elem = factory.createCollectionElementsJoin( queryableCollection, elementTable );
            LOG.debugf("No FROM element found for the elements of collection join path %s, created %s", path, elem);
        } else LOG.debugf("FROM element found for collection join path %s", path);

    // The 'from element' that represents the elements of the collection.
    setFromElement( fromElement );

    // Add the condition to the join sequence that qualifies the indexed element.
    AST selector = collectionNode.getNextSibling();
    if ( selector == null ) {
      throw new QueryException( "No index value!" );
    }

    // Sometimes use the element table alias, sometimes use the... umm... collection table alias (many to many)
    String collectionTableAlias = elementTable;
    if ( elem.getCollectionTableAlias() != null ) {
      collectionTableAlias = elem.getCollectionTableAlias();
    }

    // TODO: get SQL rendering out of here, create an AST for the join expressions.
    // Use the SQL generator grammar to generate the SQL text for the index expression.
    JoinSequence joinSequence = fromElement.getJoinSequence();
    String[] indexCols = queryableCollection.getIndexColumnNames();
    if ( indexCols.length != 1 ) {
      throw new QueryException( "composite-index appears in []: " + collectionNode.getPath() );
    }
    SqlGenerator gen = new SqlGenerator( getSessionFactoryHelper().getFactory() );
    try {
      gen.simpleExpr( selector ); //TODO: used to be exprNoParens! was this needed?
    }
    catch ( RecognitionException e ) {
      throw new QueryException( e.getMessage(), e );
    }
    String selectorExpression = gen.getSQL();
    joinSequence.addCondition( collectionTableAlias + '.' + indexCols[0] + " = " + selectorExpression );
    List paramSpecs = gen.getCollectedParameters();
    if ( paramSpecs != null ) {
      switch ( paramSpecs.size() ) {
        case 0 :
          // nothing to do
          break;
        case 1 :
          ParameterSpecification paramSpec = ( ParameterSpecification ) paramSpecs.get( 0 );
          paramSpec.setExpectedType( queryableCollection.getIndexType() );
          fromElement.setIndexCollectionSelectorParamSpec( paramSpec );
          break;
        default:
          fromElement.setIndexCollectionSelectorParamSpec(
              new AggregatedIndexCollectionSelectorParameterSpecifications( paramSpecs )
          );
          break;
      }
    }

    // Now, set the text for this node.  It should be the element columns.
    String[] elementColumns = queryableCollection.getElementColumnNames( elementTable );
    setText( elementColumns[0] );
    setResolved();
  }

  /**
   * In the (rare?) case where the index selector contains multiple parameters...
   */
  private static class AggregatedIndexCollectionSelectorParameterSpecifications implements ParameterSpecification {
    private final List paramSpecs;

    public AggregatedIndexCollectionSelectorParameterSpecifications(List paramSpecs) {
      this.paramSpecs = paramSpecs;
    }

    public int bind(PreparedStatement statement, QueryParameters qp, SessionImplementor session, int position)
    throws SQLException {
      int bindCount = 0;
      Iterator itr = paramSpecs.iterator();
      while ( itr.hasNext() ) {
        final ParameterSpecification paramSpec = ( ParameterSpecification ) itr.next();
        bindCount += paramSpec.bind( statement, qp, session, position + bindCount );
      }
      return bindCount;
    }

    public Type getExpectedType() {
      return null;
    }

    public void setExpectedType(Type expectedType) {
    }

    public String renderDisplayInfo() {
      return "index-selector [" + collectDisplayInfo() + "]" ;
    }

    private String collectDisplayInfo() {
      StringBuffer buffer = new StringBuffer();
      Iterator itr = paramSpecs.iterator();
      while ( itr.hasNext() ) {
        buffer.append( ( ( ParameterSpecification ) itr.next() ).renderDisplayInfo() );
      }
      return buffer.toString();
    }
  }
}
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