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Hibernate definition of the Java Persistence 2.0 (JSR 317) API.

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// $Id: Path.java 17752 2009-10-15 01:19:21Z [email protected] $
// EJB3 Specification Copyright 2004-2009 Sun Microsystems, Inc.
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);
}