Monday, March 30, 2009

Sorting Map berdasarkan Key atau Value di Java

Walau agak aneh sih harus bikin sorting map di java tapi siapa tau berguna.

Ini sort berdasarkan key:

@SuppressWarnings("unchecked")
public static Map sortByKey(Map map) {
List list = new LinkedList(map.entrySet());
Collections.sort(list, new Comparator() {
public int compare(Object o1, Object o2) {
return ((Comparable) ((Map.Entry) (o1)).getKey())
.compareTo(((Map.Entry) (o2)).getKey());
}
});
// logger.info(list);
Map result = new LinkedHashMap();
for (Iterator it = list.iterator(); it.hasNext();) {
Map.Entry entry = (Map.Entry) it.next();
result.put(entry.getKey(), entry.getValue());
}
return result;
}

Ini sort berdasarkan value:
@SuppressWarnings("unchecked")
public static Map sortByValue(Map map) {
List list = new LinkedList(map.entrySet());
Collections.sort(list, new Comparator() {
public int compare(Object o1, Object o2) {
return ((Comparable) ((Map.Entry) (o1)).getValue())
.compareTo(((Map.Entry) (o2)).getValue());
}
});
// logger.info(list);
Map result = new LinkedHashMap();
for (Iterator it = list.iterator(); it.hasNext();) {
Map.Entry entry = (Map.Entry) it.next();
result.put(entry.getKey(), entry.getValue());
}
return result;
}

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