javax.persistence.criteria.Path Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of javax.persistence Show documentation
javax.persistence build based upon git transaction cfcdce1
There is a newer version: 2.2.1
/*******************************************************************************
 * Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Linda DeMichiel - Java Persistence 2.1
 *     Linda DeMichiel - Java Persistence 2.0
 *
 ******************************************************************************/ 
package javax.persistence.criteria;

import javax.persistence.metamodel.PluralAttribute;
import javax.persistence.metamodel.SingularAttribute;
import javax.persistence.metamodel.Bindable;
import javax.persistence.metamodel.MapAttribute;

/**
 * Represents a simple or compound attribute path from a 
 * bound type or collection, and is a "primitive" expression.
 *
 * @param   the type referenced by the path
 *
 * @since Java Persistence 2.0
 */
public interface Path extends Expression {

    /** 
     * Return the bindable object that corresponds to the
     * path expression.
     * @return bindable object corresponding to the path
     */
    Bindable getModel(); 
    
    /**
     *  Return the parent "node" in the path or null if no parent.
     *  @return parent
     */
    Path getParentPath();
	
    /**
     *  Create a path corresponding to the referenced 
     *  single-valued attribute.
     *  @param attribute single-valued attribute
     *  @return path corresponding to the referenced attribute
     */
     Path get(SingularAttribute attribute);

    /**
     *  Create a path corresponding to the referenced 
     *  collection-valued attribute.
     *  @param collection collection-valued attribute
     *  @return expression corresponding to the referenced attribute
     */
    > Expression get(PluralAttribute collection);

    /**
     *  Create a path corresponding to the referenced 
     *  map-valued attribute.
     *  @param map map-valued attribute
     *  @return expression corresponding to the referenced attribute
     */
    > Expression get(MapAttribute map);

    /**
     *  Create an expression corresponding to the type of the path.
     *  @return expression corresponding to the type of the path
     */
    Expression> type();


    //String-based:
	
    /**
     *  Create a path corresponding to the referenced attribute.
     * 
     *   Note: Applications using the string-based API may need to 
     *  specify the type resulting from the get operation in order
     *  to avoid the use of Path variables.
     *
     *  
     *     For example:
     *
     *     CriteriaQuery<Person> q = cb.createQuery(Person.class);
     *     Root<Person> p = q.from(Person.class);
     *     q.select(p)
     *      .where(cb.isMember("joe",
     *                         p.<Set<String>>get("nicknames")));
     *
     *     rather than:
     * 
     *     CriteriaQuery<Person> q = cb.createQuery(Person.class);
     *     Root<Person> p = q.from(Person.class);
     *     Path<Set<String>> nicknames = p.get("nicknames");
     *     q.select(p)
     *      .where(cb.isMember("joe", nicknames));
     *  
     *
     *  @param attributeName  name of the attribute
     *  @return path corresponding to the referenced attribute
     *  @throws IllegalStateException if invoked on a path that
     *          corresponds to a basic type
     *  @throws IllegalArgumentException if attribute of the given
     *           name does not otherwise exist
     */
     Path get(String attributeName);
}