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    • com.vaadin.data.util.DefaultItemSorter Maven / Gradle / Ivy

    /*
 * Vaadin Framework 7
 *
 * Copyright (C) 2000-2024 Vaadin Ltd
 *
 * This program is available under Vaadin Commercial License and Service Terms.
 *
 * See  for the full
 * license.
 */
package com.vaadin.data.util;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;

import com.vaadin.data.Container;
import com.vaadin.data.Container.Sortable;
import com.vaadin.data.Item;
import com.vaadin.data.Property;

/**
 * Provides a default implementation of an ItemSorter. The
 * DefaultItemSorter adheres to the
 * {@link Sortable#sort(Object[], boolean[])} rules and sorts the container
 * according to the properties given using
 * {@link #setSortProperties(Sortable, Object[], boolean[])}.
 * 
    
 * A Comparator is used for comparing the individual Property
 * values. The comparator can be set using the constructor. If no comparator is
 * provided a default comparator is used.
 *
 */
public class DefaultItemSorter implements ItemSorter {

    private java.lang.Object[] sortPropertyIds;
    private boolean[] sortDirections;
    private Container container;
    private Comparator propertyValueComparator;

    /**
     * Constructs a DefaultItemSorter using the default Comparator
     * for comparing Propertyvalues.
     *
     */
    public DefaultItemSorter() {
        this(new DefaultPropertyValueComparator());
    }

    /**
     * Constructs a DefaultItemSorter which uses the Comparator
     * indicated by the propertyValueComparator parameter for
     * comparing Propertyvalues.
     *
     * @param propertyValueComparator
     *            The comparator to use when comparing individual
     *            Property values
     */
    public DefaultItemSorter(Comparator propertyValueComparator) {
        this.propertyValueComparator = propertyValueComparator;
    }

    /*
     * (non-Javadoc)
     *
     * @see com.vaadin.data.util.ItemSorter#compare(java.lang.Object,
     * java.lang.Object)
     */
    @Override
    public int compare(Object o1, Object o2) {
        Item item1 = container.getItem(o1);
        Item item2 = container.getItem(o2);

        /*
         * Items can be null if the container is filtered. Null is considered
         * "less" than not-null.
         */
        if (item1 == null) {
            if (item2 == null) {
                return 0;
            } else {
                return 1;
            }
        } else if (item2 == null) {
            return -1;
        }

        for (int i = 0; i < sortPropertyIds.length; i++) {

            int result = compareProperty(sortPropertyIds[i], sortDirections[i],
                    item1, item2);

            // If order can be decided
            if (result != 0) {
                return result;
            }

        }

        return 0;
    }

    /**
     * Compares the property indicated by propertyId in the items
     * indicated by item1 and item2 for order. Returns
     * a negative integer, zero, or a positive integer as the property value in
     * the first item is less than, equal to, or greater than the property value
     * in the second item. If the sortDirection is false the
     * returned value is negated.
     * 
    
     * The comparator set for this DefaultItemSorter is used for
     * comparing the two property values.
     *
     * @param propertyId
     *            The property id for the property that is used for comparison.
     * @param sortDirection
     *            The direction of the sort. A false value negates the result.
     * @param item1
     *            The first item to compare.
     * @param item2
     *            The second item to compare.
     * @return a negative, zero, or positive integer if the property value in
     *         the first item is less than, equal to, or greater than the
     *         property value in the second item. Negated if
     *         {@code sortDirection} is false.
     */
    protected int compareProperty(Object propertyId, boolean sortDirection,
            Item item1, Item item2) {

        // Get the properties to compare
        final Property property1 = item1.getItemProperty(propertyId);
        final Property property2 = item2.getItemProperty(propertyId);

        // Get the values to compare
        final Object value1 = (property1 == null) ? null : property1.getValue();
        final Object value2 = (property2 == null) ? null : property2.getValue();

        // Result of the comparison
        int r = 0;
        if (sortDirection) {
            r = propertyValueComparator.compare(value1, value2);
        } else {
            r = propertyValueComparator.compare(value2, value1);
        }

        return r;
    }

    /*
     * (non-Javadoc)
     *
     * @see com.vaadin.data.util.ItemSorter#setSortProperties(com.vaadin.data.
     * Container .Sortable, java.lang.Object[], boolean[])
     */
    @Override
    public void setSortProperties(Container.Sortable container,
            Object[] propertyId, boolean[] ascending) {
        this.container = container;

        // Removes any non-sortable property ids
        final List ids = new ArrayList();
        final List orders = new ArrayList();
        final Collection sortable = container
                .getSortableContainerPropertyIds();
        for (int i = 0; i < propertyId.length; i++) {
            if (sortable.contains(propertyId[i])) {
                ids.add(propertyId[i]);
                orders.add(Boolean
                        .valueOf(i < ascending.length ? ascending[i] : true));
            }
        }

        sortPropertyIds = ids.toArray();
        sortDirections = new boolean[orders.size()];
        for (int i = 0; i < sortDirections.length; i++) {
            sortDirections[i] = (orders.get(i)).booleanValue();
        }

    }

    /**
     * Provides a default comparator used for comparing {@link Property} values.
     * The DefaultPropertyValueComparator assumes all objects it
     * compares can be cast to Comparable.
     *
     */
    public static class DefaultPropertyValueComparator
            implements Comparator, Serializable {

        @Override
        @SuppressWarnings("unchecked")
        public int compare(Object o1, Object o2) {
            int r = 0;
            // Normal non-null comparison
            if (o1 != null && o2 != null) {
                // Assume the objects can be cast to Comparable, throw
                // ClassCastException otherwise.
                r = ((Comparable) o1).compareTo(o2);
            } else if (o1 == o2) {
                // Objects are equal if both are null
                r = 0;
            } else {
                if (o1 == null) {
                    r = -1; // null is less than non-null
                } else {
                    r = 1; // non-null is greater than null
                }
            }

            return r;
        }
    }

}
    
    
    
    

    




    
    
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