Package com.hp.hpl.squirrelrdf.rdb

Source Code of com.hp.hpl.squirrelrdf.rdb.ProcessedQuery

/*
* (c) Copyright 2006 Hewlett-Packard Development Company, LP
* All rights reserved.
* [See end of file]
*/

package com.hp.hpl.squirrelrdf.rdb;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.query.engine.QueryIterator;
import com.hp.hpl.jena.query.engine1.ExecutionContext;
import com.hp.hpl.squirrelrdf.querymap.QueryMapEngine;
import com.hp.hpl.squirrelrdf.querymap.QueryMapIterator;

/**
* ProcessedQuery
*
*
*
* @author Damian Steer <pldms@mac.com>
*/
public class ProcessedQuery
{
  final static Log log = LogFactory.getLog(ProcessedQuery.class);
 
  Map<Database,ProcessedPattern> dbToTriples;
 
  public ProcessedQuery()
  {
    this.dbToTriples = new HashMap<Database,ProcessedPattern>();
  }
 
  /**
   * Add a triple (mapped predicate -> col) to this query.
   *
   * @param subject
   * @param col
   * @param object
   */
  public void add(Node subject, Col col, Node object)
  {
    ProcessedPattern triples =
      (ProcessedPattern) dbToTriples.get(col.getDatabase());
    if (triples == null)
    {
      triples = new ProcessedPattern(col.getDatabase());
      dbToTriples.put(col.getDatabase(), triples);
    }
    triples.add(subject, col, object);
  }
 
  public void add(Node subject, Table table)
  {
    ProcessedPattern triples =
      (ProcessedPattern) dbToTriples.get(table.getDatabase());
    if (triples == null)
    {
      triples = new ProcessedPattern(table.getDatabase());
      dbToTriples.put(table.getDatabase(), triples);
    }
    triples.add(subject, table);
  }
 
  /**
   * Execute this query.
   * @param arg1
   * @param theResult An existing result to continue.
   * @return The result, a list of bindings.
   * @throws SQLException
   */
  public QueryIterator execute(QueryIterator results, ExecutionContext context) throws SQLException
  {
    /*
     * This is dumb. We just go through the triple patterns and execute
     * them in a random order.
     */
    for (QueryMapEngine subquery: dbToTriples.values())
    {
      results = new QueryMapIterator(subquery, results, context);
    }
    return results;
  }

}

/*
* (c) Copyright 2006 Hewlett-Packard Development Company, LP
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/ 
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