GroupGraphPattern.java

/*
 * Copyright 2008 Fedora Commons
 *
 * 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.mulgara.sparql.parser.cst;

import java.util.List;


/**
 * A group of triple patterns, ANDed together.
 *
 * @created Feb 18, 2008
 * @author Paula Gearon
 * @copyright © 2008 <a href="http://www.fedora-commons.org/">Fedora Commons</a>
 * @licence <a href="{@docRoot}/../LICENCE.txt">Apache License, Version 2.0</a>
 */
public interface GroupGraphPattern extends Node {
  
  /** A singleton empty graph pattern */
  public static final GroupGraphPattern EMPTY = new EmptyGraphPattern();

  /**
   * Returns all the elements at this operational level
   */
  public List<? extends GroupGraphPattern> getElements();

  /**
   * Returns all the patterns flattened from this level down.
   */
  public List<GroupGraphPattern> getAllTriples();

  /**
   * Sets the graph for an expression
   * @param g The graph the triples match on.
   */
  public void setGraph(Expression g);
  
  /**
   * @return the graph for the pattern. Either a variable or an IRI
   */
  public Expression getGraph();

  /**
   * Sets the filter for a pattern
   * @param f The filter for the matched triples
   */
  public void setFilter(Expression f);
  
  /**
   * @return the filter for the pattern.
   */
  public Expression getFilter();
}