ZTuple.java

/*
 * This file is part of Zql.
 *
 * Zql 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 3 of the License, or
 * (at your option) any later version.
 *
 * Zql 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 Zql.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.gibello.zql.data;

import java.lang.*;
import java.util.Vector;
import java.util.Hashtable;
import java.util.StringTokenizer;

import org.gibello.zql.*;

public class ZTuple {

    /**
     * the names of the attributes
     */
    private Vector attributes_;
    /**
     * the values of the attributes
     */
    private Vector values_;
    /**
     * hashtable to locate attribute names more easily
     */
    private Hashtable searchTable_;


    /**
     * The simplest constructor
     */
    public ZTuple() {
	attributes_=new Vector();
	values_=new Vector();
	searchTable_ = new Hashtable();
    }

  /**
   * Create a new tuple, given it's column names
   * @param colnames Column names separated by commas (,).
   */
  public ZTuple(String colnames) {
    this();
    StringTokenizer st = new StringTokenizer(colnames, ",");
    while(st.hasMoreTokens()) {
      setAtt(st.nextToken().trim(), null);
    }
  }

  /**
   * Set the current tuple's column values.
   * @param row Column values separated by commas (,).
   */
  public void setRow(String row) {
    StringTokenizer st = new StringTokenizer(row, ",");
    for(int i = 0; st.hasMoreTokens(); i++) {
      String val = st.nextToken().trim();
      try {
        Double d = new Double(val);
        setAtt(getAttName(i), d);
      } catch(Exception e) {
        setAtt(getAttName(i), val);
      }
    }
  }

  /**
   * Set the current tuple's column values.
   * @param row A vector of column values.
   */
  public void setRow(Vector row) {
    for(int i = 0; i < row.size(); i++) {
      setAtt(getAttName(i), row.elementAt(i));
    }
  }

    
    /**
     * Set the value of the given attribute name
     * @param name the string representing the attribute name
     * @param value the Object representing the attribute value
     */
    public void setAtt(String name, Object value)
    {
	if(name != null)
	    {
	    boolean exist = searchTable_.containsKey(name);
	    
	    if(exist)
		{
		int i = ((Integer)searchTable_.get(name)).intValue();
		values_.setElementAt(value,i);
		}
	    else
		{
		int i = attributes_.size();
		attributes_.addElement(name);
		values_.addElement(value);
		searchTable_.put(name, new Integer(i));
		}
	    }
    }

    /**
     * Return the name of the attribute corresponding to the index
     * @param index integer giving the index of the attribute
     * @return a String
    */
    public String getAttName(int index)
    {
	try
	    {
	    return (String)attributes_.elementAt(index);
	    }
	catch(ArrayIndexOutOfBoundsException e)
	    {
	    return null;
	    }
    }

    /**
     * Return the index  of the attribute corresponding to the name
     * @param index integer giving the index of the attribute
     * @return the index as an int, -1 if name is not an attribute
    */
    public int getAttIndex(String name)
    {
	if(name == null)
	    return -1;
	Integer index = (Integer)searchTable_.get(name);
	if(index != null)
	    return index.intValue();
	else
	    return -1;
    }

    /**
     * Return the value of the attribute corresponding to the index
     * @param index integer giving the index of the attribute
     * @return an Object (null if index is out of bound)
    */
    public Object getAttValue(int index)
    {
	try
	    {
	    return values_.elementAt(index);
	    }
	catch(ArrayIndexOutOfBoundsException e)
	    {
	    return null;
	    }
    }

    /**
     * Return the value of the attribute whith the given name
     * @return an Object (null if name is not an existing attribute)
    */
    public Object getAttValue(String name)
    {
	boolean exist = false;

	if(name != null)
	    exist = searchTable_.containsKey(name);
	
	if (exist)
	    {
	    int index = ((Integer)searchTable_.get(name)).intValue();
            return values_.elementAt(index);
	    }
        else
            return null;
    }

    /**
     * To know if an attributes is already defined
     * @param attrName the name of the attribute
     * @return true if there, else false
     */
    public boolean isAttribute(String attrName)
    {
	if(attrName != null)
	    return searchTable_.containsKey(attrName);
	else
	    return false;
    }
    
    /**
     * Return the number of attributes in the tupple
     * @return int the number of attributes
     */
    public int getNumAtt()
    {
	return values_.size();
    }

    /**
     * Returns a string representation of the object
     * @return a string representation of the object
     */
    public String toString()
    {
	Object att;
	Object value;
	String attS;
	String valueS;
	
	StringBuffer resp = new StringBuffer();
	resp.append("[");
	if(attributes_.size() > 0)
	    {
	    att = attributes_.elementAt(0);
	    if(att==null)
		attS = "(null)";
	    else
		attS = att.toString();
	    
	    value = values_.elementAt(0);
	    if(value==null)
		valueS = "(null)";
	    else
		valueS = value.toString();
	    resp.append(attS +" = "+ valueS);
	    }
	
	for(int i=1; i < attributes_.size(); i++)
	    {
	    att = attributes_.elementAt(i);
	    if(att==null)
		attS = "(null)";
	    else
		attS = att.toString();
	    
	    value = values_.elementAt(i);
	    if(value==null)
		valueS = "(null)";
	    else
		valueS = value.toString();
	    resp.append(", "+ attS + " = "+ valueS);
	    }
	resp.append("]");
	return resp.toString();
    }

};