ColumnComparators.java

/*!
 * This program is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 * or from the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 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 Lesser General Public License for more details.
 *
 * Copyright (c) 2002-2013 Pentaho Corporation..  All rights reserved.
 */

package org.pentaho.gwt.widgets.client.table;

import java.util.Comparator;
import java.util.Date;

import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;

/**
 * Classes for comparing columns when sorting a scroll table.
 */
public interface ColumnComparators {
  public enum ColumnComparatorTypes {
    NUMERIC, DATE, STRING_CASE, STRING_NOCASE
  }

  public abstract class BaseColumnComparator implements Comparator<Element> {
    protected boolean ascending = true;

    public static BaseColumnComparator getInstance( ColumnComparatorTypes type ) {
      switch ( type ) {
        case NUMERIC:
          return new NumericColumnComparator();
        case STRING_NOCASE:
          return new StringColumnComparator( false );
        case STRING_CASE:
          return new StringColumnComparator( true );
        case DATE:
          return new DateColumnComparator();
      }
      return null;
    }

    public boolean isAscending() {
      return ascending;
    }

    public void setAscending( boolean ascending ) {
      this.ascending = ascending;
    }

    public BaseColumnComparator( boolean ascending ) {
      this.ascending = ascending;
    }

    public BaseColumnComparator() {
    }

    protected Element getLeftObject( Element o1, Element o2 ) {
      return ascending ? o1 : o2;
    }

    protected Element getRightObject( Element o1, Element o2 ) {
      return ascending ? o2 : o1;
    }
  }

  public class NumericColumnComparator extends BaseColumnComparator {
    public int compare( Element arg0, Element arg1 ) {
      Element left = getLeftObject( arg0, arg1 );
      Element right = getRightObject( arg0, arg1 );

      // If left object is null, it is less; unless both are null, then they are equal
      if ( left == null ) {
        if ( right == null ) {
          return 0;
        }
        return -1;
      }

      Float vLeft = Float.valueOf( DOM.getInnerText( left ) );
      Float vRight = Float.valueOf( DOM.getInnerText( right ) );

      if ( vLeft < vRight ) {
        return -1;
      }
      if ( vLeft > vRight ) {
        return 1;
      }

      // Assumed equal
      return 0;
    }
  }

  public class DateColumnComparator extends BaseColumnComparator {
    @SuppressWarnings( "deprecation" )
    // GWT requires new Date(String)
    public int compare( Element arg0, Element arg1 ) {
      Element left = getLeftObject( arg0, arg1 );
      Element right = getRightObject( arg0, arg1 );

      // If left object is null, it is less; unless both are null, then they are equal
      if ( left == null ) {
        if ( right == null ) {
          return 0;
        }
        return -1;
      }

      Date vLeft = null;
      Date vRight = null;

      try {
        vLeft = new Date( DOM.getInnerText( left ) );
      } catch ( Exception ex ) {
        return -1;
      }

      try {
        vRight = new Date( DOM.getInnerText( right ) );
      } catch ( Exception ex ) {
        return 1;
      }

      if ( vLeft.before( vRight ) ) {
        return -1;
      }
      if ( vLeft.after( vRight ) ) {
        return 1;
      }

      // Assumed equal
      return 0;
    }
  }

  public class StringColumnComparator extends BaseColumnComparator {
    private boolean caseSensitive = false;

    public void setCaseSensitive( boolean caseSensitive ) {
      this.caseSensitive = caseSensitive;
    }

    public boolean isCaseSensitive() {
      return caseSensitive;
    }

    public StringColumnComparator() {
    }

    public StringColumnComparator( boolean caseSensitive ) {
      this.setCaseSensitive( caseSensitive );
    }

    public int compare( Element arg0, Element arg1 ) {
      Element left = getLeftObject( arg0, arg1 );
      Element right = getRightObject( arg0, arg1 );

      // If left object is null, it is less; unless both are null, then they are equal
      if ( left == null ) {
        if ( right == null ) {
          return 0;
        }
        return -1;
      }

      String vLeft = DOM.getInnerText( left );
      String vRight = DOM.getInnerText( right );

      if ( caseSensitive ) {
        return vLeft.compareTo( vRight );
      } else {
        return vLeft.compareToIgnoreCase( vRight );
      }
    }
  }
}