/** * Licensed under the Artistic License; you may not use this file * except in compliance with the License. * You may obtain a copy of the License at * *      http://displaytag.sourceforge.net/license.html * * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */package org.displaytag.model;import java.util.Comparator;import org.apache.commons.lang.builder.EqualsBuilder;import org.apache.commons.lang.builder.HashCodeBuilder;import org.displaytag.decorator.TableDecorator;import org.displaytag.exception.ObjectLookupException;import org.displaytag.exception.RuntimeLookupException;import org.displaytag.util.LookupUtil;/** * Comparator for rows. * @author Fabrizio Giustina * @version $Revision: 1139 $ ($Author: fgiust $) */public class RowSorter implements Comparator{    /**     * name of the property in bean.     */    private String property;    /**     * table decorator.     */    private TableDecorator decorator;    /**     * sort order ascending?     */    private boolean ascending;    /**     * Index of the sorted column.     */    private int columnIndex;    /**     * Comparator used for comparisons.     */    private Comparator comparator;    /**     * Initialize a new RowSorter.     * @param sortedColumnIndex index of the sorted column     * @param beanProperty name of the property. If pProperty is null column index is used to get a static cell value     * from the row object     * @param tableDecorator TableDecorator instance     * @param ascendingOrder boolean ascending order?     * @param compar the comparator to use     */    public RowSorter(        int sortedColumnIndex,        String beanProperty,        TableDecorator tableDecorator,        boolean ascendingOrder,        Comparator compar)    {        this.columnIndex = sortedColumnIndex;        this.property = beanProperty;        this.decorator = tableDecorator;        this.ascending = ascendingOrder;        this.comparator = compar;        if (compar == null)        {            throw new IllegalArgumentException(                "A null comparator has been passed to RowSorter. A comparator instance is required");        }    }    /**     * Compares two objects by first fetching a property from each object and then comparing that value. If there are     * any errors produced while trying to compare these objects then a RunTimeException will be thrown as any error     * found here will most likely be a programming error that needs to be quickly addressed (like trying to compare     * objects that are not comparable, or trying to read a property from a bean that is invalid, etc...)     * @param object1 Object     * @param object2 Object     * @return int     * @see java.util.Comparator#compare(Object, Object)     */    public final int compare(Object object1, Object object2)    {        Object obj1 = null;        Object obj2 = null;        // if property is null compare using two static cell objects        if (this.property == null)        {            if (object1 instanceof Row)            {                obj1 = ((Row) object1).getCellList().get(this.columnIndex);            }            if (object2 instanceof Row)            {                obj2 = ((Row) object2).getCellList().get(this.columnIndex);            }            return checkNullsAndCompare(obj1, obj2);        }        if (object1 instanceof Row)        {            obj1 = ((Row) object1).getObject();        }        if (object2 instanceof Row)        {            obj2 = ((Row) object2).getObject();        }        try        {            Object result1;            Object result2;            // If they have supplied a decorator, then make sure and use it for the sorting as well            if (this.decorator != null && this.decorator.hasGetterFor(this.property))            {                // set the row before sending to the decorator                this.decorator.initRow(obj1, 0, 0);                result1 = LookupUtil.getBeanProperty(this.decorator, this.property);                // set the row before sending to the decorator                this.decorator.initRow(obj2, 0, 0);                result2 = LookupUtil.getBeanProperty(this.decorator, this.property);            }            else            {                result1 = LookupUtil.getBeanProperty(obj1, this.property);                result2 = LookupUtil.getBeanProperty(obj2, this.property);            }            return checkNullsAndCompare(result1, result2);        }        catch (ObjectLookupException e)        {            throw new RuntimeLookupException(getClass(), this.property, e);        }    }    /**     * Compares two given objects, and handles the case where nulls are present.     * @param object1 first object to compare     * @param object2 second object to compare     * @return int result     */    private int checkNullsAndCompare(Object object1, Object object2)    {        int returnValue;        if (object1 == null && object2 != null)        {            returnValue = -1;        }        else if (object1 != null && object2 == null)        {            returnValue = 1;        }        else if (object1 == null && object2 == null)        {            // both null            returnValue = 0;        }        else        {            returnValue = comparator.compare(object1, object2);        }        int ascendingInt = this.ascending ? 1 : -1;        return ascendingInt * returnValue;    }    /**     * Is this Comparator the same as another one?     * @param object Object     * @return boolean     * @see java.util.Comparator#equals(Object)     */    public final boolean equals(Object object)    {        if (object instanceof RowSorter)        {            return new EqualsBuilder().append(this.property, ((RowSorter) object).property).append(                this.columnIndex,                ((RowSorter) object).columnIndex).isEquals();        }        return false;    }    /**     * @see java.lang.Object#hashCode()     */    public final int hashCode()    {        return new HashCodeBuilder(31, 33).append(this.property).append(this.columnIndex).toHashCode();    }}