Package de.dlr.proseo.ui.gui.service

Class MapComparator

java.lang.Object

de.dlr.proseo.ui.gui.service.MapComparator

All Implemented Interfaces:

Comparator<Object>

public class MapComparator
extends Object
implements Comparator<Object>

A class for comparing HashMap objects based on one or two specified keys

Author:

Ernst Melchinger

Field Summary

Fields

Modifier and Type	Field	Description
(package private) String	key	the first key to compare
(package private) String	key2	the second key to compare
(package private) Boolean	up	the sorting order

Constructor Summary

Constructors

Constructor	Description
MapComparator(String key, Boolean up)	Constructor that takes a key and a boolean argument for the sorting order
MapComparator(String key, String key2, Boolean up)	Constructor that takes two keys and a boolean argument for the sorting order

Method Summary

Modifier and Type	Method	Description
int	compare(Object object1, Object object2)	Compares two objects, checks whether they are instances of HashMap and then extracts the values associated with the specified keys from each HashMap.

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

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Details

key

String key

the first key to compare

key2

String key2

the second key to compare

up

Boolean up

the sorting order

Constructor Details

MapComparator

public MapComparator(String key,
 Boolean up)

Constructor that takes a key and a boolean argument for the sorting order

Parameters:

key - the key to look for in compared hash maps

up - true, if the comparison is to be made in ascending order, false otherwise

MapComparator

public MapComparator(String key,
 String key2,
 Boolean up)

Constructor that takes two keys and a boolean argument for the sorting order

Parameters:

key - the key to look for in compared hash maps

key2 - the second key to look for

up - true, if the comparison is to be made in ascending order, false otherwise

Method Details

compare

public int compare(Object object1,
 Object object2)

Compares two objects, checks whether they are instances of HashMap and then extracts the values associated with the specified keys from each HashMap.

Specified by:

compare in interface Comparator<Object>

Parameters:

object1 - the first object (HashMap) to compare

object2 - the second object (HashMap) to compare

Returns:

a negative value if the first object should be placed before the second object, a positive value if the first object should be placed after the second object, or zero if the objects are either not HashMaps, or null, or their keys neither integer nor string, or considered equal in terms of sorting