Hibernate example source code file (CriteriaQueryImpl.java)

This example Hibernate source code file (CriteriaQueryImpl.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

class, criteriaquery, criteriaquery, illegalstateexception, illegalstateexception, io, list, root, selection, selection, selectionimplementor, set, suppresswarnings, t, t, util

The Hibernate CriteriaQueryImpl.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2009 by Red Hat Inc and/or its affiliates or by
 * third-party contributors as indicated by either @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.ejb.criteria;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import javax.persistence.Tuple;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Expression;
import javax.persistence.criteria.Order;
import javax.persistence.criteria.ParameterExpression;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import javax.persistence.criteria.Selection;
import javax.persistence.criteria.Subquery;
import javax.persistence.metamodel.EntityType;
import org.hibernate.ejb.HibernateEntityManagerImplementor;
import org.hibernate.type.Type;

/**
 * The Hibernate implementation of the JPA {@link CriteriaQuery} contract.  Mostly a set of delegation to its
 * internal {@link QueryStructure}.
 *
 * @author Steve Ebersole
 */
public class CriteriaQueryImpl<T> extends AbstractNode implements CriteriaQuery, Serializable {
	private final Class<T> returnType;

	private final QueryStructure<T> queryStructure;
	private List<Order> orderSpecs = Collections.emptyList();


	public CriteriaQueryImpl(
			CriteriaBuilderImpl criteriaBuilder,
			Class<T> returnType) {
		super( criteriaBuilder );
		this.returnType = returnType;
		this.queryStructure = new QueryStructure<T>( this, criteriaBuilder );
	}

	/**
	 * {@inheritDoc}
	 */
	public Class<T> getResultType() {
		return returnType;
	}


	// SELECTION ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> distinct(boolean applyDistinction) {
		queryStructure.setDistinct( applyDistinction );
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public boolean isDistinct() {
		return queryStructure.isDistinct();
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings({ "unchecked" })
	public Selection<T> getSelection() {
		return ( Selection<T> ) queryStructure.getSelection();
	}

	public void applySelection(Selection<? extends T> selection) {
		queryStructure.setSelection( selection );
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> select(Selection selection) {
		applySelection( selection );
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings({ "unchecked" })
	public CriteriaQuery<T> multiselect(Selection... selections) {
		return multiselect( Arrays.asList( selections ) );
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings({ "unchecked" })
	public CriteriaQuery<T> multiselect(List> selections) {
		final Selection<? extends T> selection;

		if ( Tuple.class.isAssignableFrom( getResultType() ) ) {
			selection = ( Selection<? extends T> ) criteriaBuilder().tuple( selections );
		}
		else if ( getResultType().isArray() ) {
			selection = ( Selection<? extends T> )  criteriaBuilder().array(
					( Class<? extends Object[]> ) getResultType(),
					selections
			);
		}
		else if ( Object.class.equals( getResultType() ) ) {
			switch ( selections.size() ) {
				case 0: {
					throw new IllegalArgumentException(
							"empty selections passed to criteria query typed as Object"
					);
				}
				case 1: {
					selection = ( Selection<? extends T> ) selections.get( 0 );
					break;
				}
				default: {
					selection = ( Selection<? extends T> ) criteriaBuilder().array( selections );
				}
			}
		}
		else {
			selection = criteriaBuilder().construct( getResultType(), selections );
		}
		applySelection( selection );
		return this;
	}


	// ROOTS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/**
	 * {@inheritDoc}
	 */
	public Set<Root getRoots() {
		return queryStructure.getRoots();
	}

	/**
	 * {@inheritDoc}
	 */
	public <X> Root from(EntityType entityType) {
		return queryStructure.from( entityType );
	}

	/**
	 * {@inheritDoc}
	 */
	public <X> Root from(Class entityClass) {
		return queryStructure.from( entityClass );
	}


	// RESTRICTION ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/**
	 * {@inheritDoc}
	 */
	public Predicate getRestriction() {
		return queryStructure.getRestriction();
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> where(Expression expression) {
		queryStructure.setRestriction( criteriaBuilder().wrap( expression ) );
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> where(Predicate... predicates) {
		// TODO : assuming this should be a conjuntion, but the spec does not say specifically...
		queryStructure.setRestriction( criteriaBuilder().and( predicates ) );
		return this;
	}


	// GROUPING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/**
	 * {@inheritDoc}
	 */
	public List<Expression getGroupList() {
		return queryStructure.getGroupings();
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> groupBy(Expression... groupings) {
		queryStructure.setGroupings( groupings );
		return this;
	}

	public CriteriaQuery<T> groupBy(List> groupings) {
		queryStructure.setGroupings( groupings );
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public Predicate getGroupRestriction() {
		return queryStructure.getHaving();
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> having(Expression expression) {
		queryStructure.setHaving( criteriaBuilder().wrap( expression ) );
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> having(Predicate... predicates) {
		queryStructure.setHaving( criteriaBuilder().and( predicates ) );
		return this;
	}


	// ORDERING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/**
	 * {@inheritDoc}
	 */
	public List<Order> getOrderList() {
		return orderSpecs;
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> orderBy(Order... orders) {
		if ( orders != null && orders.length > 0 ) {
			orderSpecs = Arrays.asList( orders );
		}
		else {
			orderSpecs = Collections.emptyList();
		}
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public CriteriaQuery<T> orderBy(List orders) {
		orderSpecs = orders;
		return this;
	}

	/**
	 * {@inheritDoc}
	 */
	public Set<ParameterExpression getParameters() {
		return queryStructure.getParameters();
	}

	/**
	 * {@inheritDoc}
	 */
	public <U> Subquery subquery(Class subqueryType) {
		return queryStructure.subquery( subqueryType );
	}

	public void validate() {
		// getRoots() is explicitly supposed to return empty if none defined, no need to check for null
		if ( getRoots().isEmpty() ) {
			throw new IllegalStateException( "No criteria query roots were specified" );
		}

		// if there is not an explicit selection, there is an *implicit* selection of the root entity provided only
		// a single query root was defined.
		if ( getSelection() == null && !hasImplicitSelection() ) {
			throw new IllegalStateException( "No explicit selection and an implicit one cold not be determined" );
		}
	}

	/**
	 * If no explicit selection was defined, we have a condition called an implicit selection if the query specified
	 * a single {@link Root} and the java type of that {@link Root root's} model is the same as this criteria's
	 * {@link #getResultType() result type}.
	 *
	 * @return True if there is an explicit selection; false otherwise.
	 */
	private boolean hasImplicitSelection() {
		if ( getRoots().size() != 1 ) {
			return false;
		}

		Root root = getRoots().iterator().next();
		if ( root.getModel().getJavaType() != returnType ) {
			return false;
		}

		// if we get here, the query defined no selection but defined a single root of the same type as the
		// criteria query return, so we use that as the implicit selection
		//
		// todo : should we put an implicit marker in the selection to this fact to make later processing easier?
		return true;
	}

	public CriteriaQueryCompiler.RenderedCriteriaQuery render(CriteriaQueryCompiler.RenderingContext renderingContext) {
		final StringBuilder jpaqlQuery = new StringBuilder();

		queryStructure.render( jpaqlQuery, renderingContext );

		if ( ! getOrderList().isEmpty() ) {
			jpaqlQuery.append( " order by " );
			String sep = "";
			for ( Order orderSpec : getOrderList() ) {
				jpaqlQuery.append( sep )
						.append( ( ( Renderable ) orderSpec.getExpression() ).render( renderingContext ) )
						.append( orderSpec.isAscending() ? " asc" : " desc" );
				sep = ", ";
			}
		}

		return new CriteriaQueryCompiler.RenderedCriteriaQuery() {
			public String getQueryString() {
				return jpaqlQuery.toString();
			}

			@SuppressWarnings({ "unchecked" })
			public List<ValueHandlerFactory.ValueHandler> getValueHandlers() {
				SelectionImplementor selection = (SelectionImplementor) queryStructure.getSelection();
				return selection == null
						? null
						: selection.getValueHandlers();
			}

			public HibernateEntityManagerImplementor.Options.ResultMetadataValidator getResultMetadataValidator() {
				return new HibernateEntityManagerImplementor.Options.ResultMetadataValidator() {
					public void validate(Type[] returnTypes) {
						SelectionImplementor selection = (SelectionImplementor) queryStructure.getSelection();
						if ( selection != null ) {
							if ( selection.isCompoundSelection() ) {
								if ( returnTypes.length != selection.getCompoundSelectionItems().size() ) {
									throw new IllegalStateException(
											"Number of return values [" + returnTypes.length +
													"] did not match expected [" +
													selection.getCompoundSelectionItems().size() + "]"
									);
								}
							}
							else {
								if ( returnTypes.length > 1 ) {
									throw new IllegalStateException(
											"Number of return values [" + returnTypes.length +
													"] did not match expected [1]"
									);
								}
							}
						}
					}
				};
			}
		};
	}
}