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

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jakarta.persistence-api Show documentation
There is a newer version: 3.2.0
Show newest version
/*
 * Copyright (c) 2008, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Linda DeMichiel - 2.1
//     Linda DeMichiel - 2.0

package jakarta.persistence.criteria;

import jakarta.persistence.metamodel.PluralAttribute;
import jakarta.persistence.metamodel.SingularAttribute;
import jakarta.persistence.metamodel.Bindable;
import jakarta.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 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);
}