package org.apache.commons.collections.comparators;
/*
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 *  The Apache Software License, Version 1.1
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 *  "This product includes software developed by the
 *  Apache Software Foundation (http://www.apache.org/)."
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 *  if and wherever such third-party acknowledgments normally appear.
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import java.io.Serializable;
import java.util.Comparator;
import org.apache.commons.beanutils.PropertyUtils;
import java.math.BigDecimal;

/**
 *  allows you to pass the name of a method in and compare two beans
 *
 *@author     <a href="mailto:epugh@upstate.com">Eric Pugh</a>
 *@created    May 5, 2002
 */
public class BeanComparator implements Comparator, Serializable {

	private String compareProperty;
	private Comparator comparator;


	/**
	 *  Creates a Bean comparator that calls the property specified on the objects.
	 *  If you pass in a null, the BeanComparator defaults to comparingbasedon the
	 *  natiural order
	 *
	 *@param  compareProperty  Description of Parameter
	 */
	public BeanComparator( String compareProperty ) {
		this( compareProperty, null );
	}

	/**
	 *  Creates a comparator that compares objects based on the method name of two
	 *  JavaBeans
	 *
	 *@param  compareProperty  The method to call to compare to beans
	 *@param  comparator       The comparator to call afterwords!
	 */
	public BeanComparator( String compareProperty, Comparator comparator ) {
		setCompareProperty( compareProperty );
		if ( comparator != null ) {
			this.comparator = comparator;
		}
		else {
			this.comparator = ComparableComparator.getInstance();
		}

	}

	/**
	 *  Sets the method to be called to compare two JavaBeans
	 *
	 *@param  compareProperty  The method to call to compare to beans
	 */
	public void setCompareProperty( String compareProperty ) {
		this.compareProperty = compareProperty;
	}


	/**
	 *  Gets the compareProperty attribute of the BeanComparator
	 *
	 *@return    Gets the method to call to compare to beans
	 */
	public String getCompareProperty() {
		return compareProperty;
	}

	/**
	 *  Compare two JavaBeans by invoking the property specified in
	 *  compareProperty.
	 *
	 *@param  o1  The first bean to get data from to compare against
	 *@param  o2  The second bean to get data from to compare
	 *@return     Either a negative integer, 0, or a postitive integer
	 *@see        org.apache.commons.collections.comparators.BeanComparator#setCompareProperty()
	 */
	public int compare( Object o1, Object o2 ) {
		try {
			Comparable value1 = (Comparable) PropertyUtils.getProperty( o1, compareProperty );
			Comparable value2 = (Comparable) PropertyUtils.getProperty( o2, compareProperty );
			return comparator.compare( value1, value2 );
		}
		catch ( Exception e ) {
			throw new ClassCastException( e.toString() );
		}
	}

}