org.modeshape.jcr.api.query.qom.SetQueryObjectModel Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.modeshape.jcr.api.query.qom;
import javax.jcr.query.Query;
import javax.jcr.query.qom.QueryObjectModel;
import javax.jcr.query.qom.QueryObjectModelFactory;
/**
* A set query extension to the JCR query object model.
*
* The JCR query object model describes the queries that can be evaluated by a JCR repository independent of any particular query
* language, such as SQL. JCR defines the {@link QueryObjectModel} interface as the primary representatino of this query object
* model, but this interface is not sufficient for certain queries, such as unions or intersections of other queries. This
* interface is an extension to the JCR API that mirrors the QueryObjectModel interface for set queries.
*
*
* A query consists of:
*
* - a source. When the query is evaluated, the source evaluates its selectors and the joins between them to produce a (possibly
* empty) set of node-tuples. This is a set of 1-tuples if the query has one selector (and therefore no joins), a set of 2-tuples
* if the query has two selectors (and therefore one join), a set of 3-tuples if the query has three selectors (two joins), and so
* forth.
* - an optional constraint. When the query is evaluated, the constraint filters the set of node-tuples.
* - a list of zero or more orderings. The orderings specify the order in which the node-tuples appear in the query results. The
* relative order of two node-tuples is determined by evaluating the specified orderings, in list order, until encountering an
* ordering for which one node-tuple precedes the other. If no orderings are specified, or if for none of the specified orderings
* does one node-tuple precede the other, then the relative order of the node-tuples is implementation determined (and may be
* arbitrary).
* - a list of zero or more columns to include in the tabular view of the query results. If no columns are specified, the
* columns available in the tabular view are implementation determined, but minimally include, for each selector, a column for
* each single-valued non-residual property of the selector's node type.
*
*
* The query object model representation of a query is created by factory methods in the {@link QueryObjectModelFactory}.
*
* @see QueryObjectModel
*/
public interface SetQueryObjectModel extends SetQuery, Query {
}