de.hybris.platform.webservices.objectgraphtransformer

Class DynamicComparator

java.lang.Object

de.hybris.platform.webservices.objectgraphtransformer.DynamicComparator

All Implemented Interfaces:

java.util.Comparator<java.lang.Object>

public class DynamicComparator
extends java.lang.Object
implements java.util.Comparator<java.lang.Object>

The purpose of this class is to compare objects (of any type) using their javaBean property (getter method) values. This means it checks if both objects passed to compare() method have the same javaBean property (property name is given in constructor), then it reads the property values from both objects and then it compares these values (assuming the values are themselves objects that implements java.lang.Comparable). If a property with a given name does not exist on objects being compared (or this property returns a value that is not Comparable), this comparator has a fallback mechanism that compares objects directly, assuming that both objects have the same runtime class and this class implements java.lang.Comparable. The property name to use for comparison is set at the construction time and cannot be changed. It means that single instance of this class can be used to compare only using one property. The property used to compare objects must be a valid javaBean property (getter method must exist) and it must return a type that implements java.lang.Comparable.

Known limitations:

• The classes of objects being compared must be accessible. Package-private classes won't work. Anonymous inner classes won't work for the same reason
• The code checks if BOTH objects passed to compare(Object, Object) method have the same property and that return type of these properties are the same (so for now this comparator will not work with covariant return types).

Constructor Summary

Constructors

Constructor and Description
DynamicComparator(java.lang.String propertyName) Convienience constructor that is the same as DynamicComparator(propertyName, false);
DynamicComparator(java.lang.String propertyName, boolean reversedOrder) Creates instance that compares objects by specified javaBean-style property using specified order (normal or reversed).

Method Summary

Modifier and Type	Method and Description
int	compare(java.lang.Object object1, java.lang.Object object2)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

DynamicComparator

public DynamicComparator(java.lang.String propertyName)

Convienience constructor that is the same as DynamicComparator(propertyName, false);

DynamicComparator

public DynamicComparator(java.lang.String propertyName,
                         boolean reversedOrder)

Creates instance that compares objects by specified javaBean-style property using specified order (normal or reversed).

Parameters:

propertyName - name of the property that will be used to do comparison. This property must exist on both objects passed to compare(Object, Object) method and it must return a ReferenceType that implements java.lang.Comparable (this excludes java primitive types and arrays)

reversedOrder - if equals true, the comparison order is reversed. It is normal (so called "natural") order otherwise.

Method Detail

compare

public int compare(java.lang.Object object1,
                   java.lang.Object object2)

Specified by:

compare in interface java.util.Comparator<java.lang.Object>