Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that represents a structured query, and can be

 *             constructed from an XML serialization conforming to

 *             pathquery.dtd. The printSQL() method can be used to print

 *             a SQL serialization of the query.

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Matt Jones

 *

 *   '$Author: jones $'

 *     '$Date: 2006-11-10 10:25:38 -0800 (Fri, 10 Nov 2006) $'

 * '$Revision: 3077 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat;

import edu.ucsb.nceas.dbadapter.*;

import java.io.*;

import java.util.Hashtable;

import java.util.Stack;

import java.util.Vector;

import java.util.Enumeration;

import org.apache.log4j.Logger;

 /** a utility class that represents a group of terms in a query */

public  class QueryGroup {

    private String operator = null;  // indicates how query terms are combined

    private Vector children = null;  // the list of query terms and groups

    private int countPercentageSearchItem = 0;

    private static Logger logMetacat = Logger.getLogger(QueryGroup.class);

    /**

     * construct a new QueryGroup

     *

     * @param operator the boolean conector used to connect query terms

     *                    in this query group

     */

    public QueryGroup(String operator) {

      this.operator = operator;

      children = new Vector();

    }

    /**

     * Add a child QueryGroup to this QueryGroup

     *

     * @param qgroup the query group to be added to the list of terms

     */

    public void addChild(QueryGroup qgroup) {

      children.add((Object)qgroup);

    }

    /**

     * Add a child QueryTerm to this QueryGroup

     *

     * @param qterm the query term to be added to the list of terms

     */

    public void addChild(QueryTerm qterm) {

      children.add((Object)qterm);

    }

    /**

     * Retrieve an Enumeration of query terms for this QueryGroup

     */

    public Enumeration getChildren() {

      return children.elements();

    }

    public int getPercentageSymbolCount()

    {

      return countPercentageSearchItem;

    }

    /**

     * create a SQL serialization of the query that this instance represents

     */

    public String printSQL(boolean useXMLIndex) {

      StringBuffer self = new StringBuffer();

      StringBuffer queryString = new StringBuffer();

      boolean first = true;

      Enumeration en= getChildren();

      while (en.hasMoreElements()) {

        Object qobject = en.nextElement();

        if (qobject instanceof QueryGroup) {

            QueryGroup qg = (QueryGroup)qobject;

        	String queryGroupSQL = qg.printSQL(useXMLIndex);

        	logMetacat.info("In QueryGroup.printSQL.. found a QueryGroup: " 

        			+ queryGroupSQL);

        	if (first) {

        		first = false;

        	} else {

        		if(!queryString.toString().equals("") && queryGroupSQL != null &&!queryGroupSQL.equals("")){

                    queryString.append(" " + operator + " ");

        		}

        	}

   		  	queryString.append(queryGroupSQL);

   		  	// count percerntage number

   		  	int count = qg.getPercentageSymbolCount();

   		  	countPercentageSearchItem = countPercentageSearchItem + count;

        } else if (qobject instanceof QueryTerm) {

           QueryTerm qt = (QueryTerm)qobject;

           String termQueryString = qt.printSQL(useXMLIndex);

       	   logMetacat.info("In QueryGroup.printSQL.. found a QueryGroup: " 

        			+ termQueryString);

           if(!(qt.getSearchMode().equals("contains") && qt.getValue().equals("%"))){

        	   if (first) {

                   first = false;

               } else {

                   if(!queryString.toString().equals("")){

                       queryString.append(" " + operator + " ");

                   }

               }

               queryString.append(termQueryString);

           }

           // count percerntage number

           int count = qt.getPercentageSymbolCount();

           countPercentageSearchItem = countPercentageSearchItem + count;

        } else {

          System.err.println("qobject wrong type: fatal error");

        }

      }

      if(!queryString.toString().equals("")){

          self.append("(");

          self.append(queryString.toString());

          self.append(")");

      }

      logMetacat.info("In QueryGroup.printSQL.. final query returned is: " 

			+ self.toString());

      return self.toString();

    }

    /**

     * create a String description of the query that this instance represents.

     * This should become a way to get the XML serialization of the query.

     */

    public String toString() {

      StringBuffer self = new StringBuffer();

      self.append("  (Query group operator=" + operator + "\n");

      Enumeration en= getChildren();

      while (en.hasMoreElements()) {

        Object qobject = en.nextElement();

        self.append(qobject);

      }

      self.append("  )\n");

      return self.toString();

    }

  }