Example usage for org.apache.commons.collections ComparatorUtils nullLowComparator

Introduction

In this page you can find the example usage for org.apache.commons.collections ComparatorUtils nullLowComparator.

Prototype

public static Comparator nullLowComparator(Comparator comparator) 

Source Link

Document

Gets a Comparator that controls the comparison of null values.

Usage

From source file:com.xpn.xwiki.objects.ElementComparator.java

/**
 * Compares two objects (that implement ElementInterface) by name according 
 * to the rules for the compare method.//from w  w w  .j a v a  2s .c o  m
 * 
 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
 */
public int compare(Object o1, Object o2) {
    // Get a null comparator that is backed by a static "natural" comparator
    Comparator c = ComparatorUtils.nullLowComparator(null);

    // convert o1 and o2 into the string names when not null
    Object no1 = (o1 == null) ? null : ((ElementInterface) o1).getName();
    Object no2 = (o2 == null) ? null : ((ElementInterface) o2).getName();

    // let the null comparator handle possible null values, where null < non-null string
    return c.compare(no1, no2);
}

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From source file:org.opensingular.lib.wicket.util.lambda.ILambdasMixin.java

@SuppressWarnings("unchecked")
default <T, R extends Comparable<R>> Comparator<T> compareWith(IFunction<T, R> func) {
    return (T a, T b) -> ComparatorUtils.nullLowComparator(Comparator.naturalOrder()).compare(func.apply(a),
            func.apply(b));//from   w  ww  . j a  v  a2 s  . c o m
}

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From source file:org.openvpms.report.jasper.IMObjectCollectionDataSource.java

/**
 * Sorts a list of IMObjects on a node in the form specified by {@link NodeResolver}.
 *
 * @param objects  the objects to sort//w w w  .j av  a2 s . c o  m
 * @param sortNode the node to sort on
 */
@SuppressWarnings("unchecked")
private void sort(List<IMObject> objects, String sortNode) {
    Comparator comparator = ComparatorUtils.naturalComparator();
    comparator = ComparatorUtils.nullLowComparator(comparator);

    Transformer transformer = new NodeTransformer(sortNode, getArchetypeService());
    TransformingComparator transComparator = new TransformingComparator(transformer, comparator);
    Collections.sort(objects, transComparator);
}

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From source file:org.openvpms.web.component.im.util.IMObjectSorter.java

/**
 * Returns a new comparator to sort in ascending or descending order.
 * <p/>/*from   w w  w  . j a va2s . co  m*/
 * This comparator handles nulls.
 *
 * @param ascending if <tt>true</tt> sort in ascending order; otherwise sort in descending order
 * @return a new comparator
 */
public static Comparator getComparator(boolean ascending) {
    Comparator comparator = ComparatorUtils.naturalComparator();

    // handle nulls.
    comparator = ComparatorUtils.nullLowComparator(comparator);
    if (!ascending) {
        comparator = ComparatorUtils.reversedComparator(comparator);
    }
    return comparator;
}

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