Example usage for java.util Collections sort

Introduction

In this page you can find the example usage for java.util Collections sort.

Prototype

@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> void sort(List<T> list, Comparator<? super T> c)

Source Link

Document

Sorts the specified list according to the order induced by the specified comparator.

Usage

From source file:Main.java

@SuppressWarnings("unchecked")
public static HashMap<?, ?> sortByValue(HashMap<?, ?> map, final int flag) {
    // flag = 0 decreasing order otherwise increasing
    List list = new LinkedList(map.entrySet());
    Collections.sort(list, new Comparator() {
        public int compare(Object o1, Object o2) {
            if (flag == 0)
                return ((Comparable) ((Map.Entry) (o2)).getValue()).compareTo(((Map.Entry) (o1)).getValue());
            else/*  w w  w  .java2s . c  o  m*/
                return ((Comparable) ((Map.Entry) (o1)).getValue()).compareTo(((Map.Entry) (o2)).getValue());
        }
    });

    HashMap 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;
}

From source file:Main.java

public static <K, V extends Comparable<? super V>> List<Map.Entry<K, V>> sortMapByValue(Map<K, V> map,
        final boolean reverse) {
    if (isEmpty(map)) {
        return null;
    }//from  w w w  .  j a  va 2s . com

    List<Map.Entry<K, V>> list = new ArrayList<Map.Entry<K, V>>(map.entrySet());

    Collections.sort(list, new Comparator<Map.Entry<K, V>>() {

        public int compare(Map.Entry<K, V> entry1, Map.Entry<K, V> entry2) {
            int result = entry1.getValue().compareTo(entry2.getValue());
            if (reverse) {
                result *= -1;
            }

            return result;
        }
    });

    return list;
}

From source file:Main.java

@SuppressWarnings({ "unchecked", "rawtypes" })
public static HashMap<?, ?> sortByValue(HashMap<?, ?> map, final int flag) {
    // flag = 0 decreasing order otherwise increasing
    List<Map.Entry<?, ?>> list = new LinkedList<Map.Entry<?, ?>>(map.entrySet());
    Collections.sort(list, new Comparator() {
        public int compare(Object o1, Object o2) {
            if (flag == 0)
                return ((Comparable) ((Map.Entry) (o2)).getValue()).compareTo(((Map.Entry) (o1)).getValue());
            else/*from  www . j a v a2 s.  c  o m*/
                return ((Comparable) ((Map.Entry) (o1)).getValue()).compareTo(((Map.Entry) (o2)).getValue());
        }
    });

    HashMap 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;
}

From source file:Main.java

@SuppressWarnings({ "unchecked", "rawtypes" })
public static List<Set<Entry<String, Object>>> sortMapByKey(Map<String, ? extends Object> map) {
    if (map == null) {
        return null;
    }//from  ww w  .  j  av  a2 s  . com
    List<Set<Entry<String, Object>>> returnlist = new LinkedList(map.entrySet());
    Collections.sort(returnlist, new Comparator() {
        public int compare(Object o1, Object o2) {
            return ((Comparable) ((Map.Entry) (o1)).getKey()).compareTo(((Map.Entry) (o2)).getKey());
        }
    });
    return returnlist;
}

From source file:Main.java

public static List<String> getSortedGPXFilenamesByDate(File dir, boolean absolutePath) {
    final Map<String, Long> mp = new HashMap<String, Long>();
    readGpxDirectory(dir, mp, "", absolutePath);
    ArrayList<String> list = new ArrayList<String>(mp.keySet());
    Collections.sort(list, new Comparator<String>() {
        @Override//  w w w  .j  a va 2  s  .  c o m
        public int compare(String object1, String object2) {
            Long l1 = mp.get(object1);
            Long l2 = mp.get(object2);
            long lhs = l1 == null ? 0 : l1.longValue();
            long rhs = l2 == null ? 0 : l2.longValue();
            return lhs < rhs ? 1 : (lhs == rhs ? 0 : -1);
        }
    });
    return list;
}

From source file:Main.java

public static <E, V extends Comparable<? super V>, K> Map<K, V> sortByValueAsc(Map<K, V> map, int limit) {
    List<Map.Entry<K, V>> list = new LinkedList<Map.Entry<K, V>>(map.entrySet());
    Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
        public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2) {
            return (o1.getValue()).compareTo(o2.getValue());
        }//  www .j ava 2 s .  co  m
    });

    Map<K, V> result = new LinkedHashMap<K, V>();
    int counter = 0;
    for (Map.Entry<K, V> entry : list) {
        if (limit > 0 && counter >= limit) {
            break;
        }
        result.put(entry.getKey(), entry.getValue());
        counter++;
    }
    return result;
}

From source file:Main.java

/**
 * map sort/*from  w w  w  .ja  v  a  2  s .  com*/
 * @param map
 * @param compator
 * @return
 */
public static <K, V> Map<K, V> sortMap(Map<K, V> map, Comparator<Entry<K, V>> compator) {
    Map<K, V> result = new LinkedHashMap<K, V>();
    List<Entry<K, V>> entries = new ArrayList<Entry<K, V>>(map.entrySet());
    Collections.sort(entries, compator);
    for (Entry<K, V> entry : entries) {
        result.put(entry.getKey(), entry.getValue());
    }
    return result;
}

From source file:Main.java

public static <O> List<O> sort(List<O> collection, Comparator<? super O> comparator, boolean clone) {
    if (collection == null)
        return collection;

    if (clone) {/*from w w w.  j a  va  2 s.  c o  m*/
        collection = new ArrayList<O>(collection);
    }

    Collections.sort(collection, comparator);
    return collection;
}

From source file:Main.java

/**
 * sort Map by key desc//from www.ja  v  a 2s.  c  om
 * 
 * @param unsortMap
 * @return
 */
@SuppressWarnings({ "unchecked", "rawtypes" })
public static Map sortByComparator(Map unsortMap) {

    List list = new LinkedList(unsortMap.entrySet());

    // sort list based on comparator
    Collections.sort(list, new Comparator() {
        public int compare(Object o1, Object o2) {
            return ((Comparable) ((Map.Entry) (o1)).getKey()).compareTo(((Map.Entry) (o2)).getKey());
        }
    });

    // put sorted list into map again
    Map sortedMap = new LinkedHashMap();
    for (Iterator it = list.iterator(); it.hasNext();) {
        Map.Entry entry = (Map.Entry) it.next();
        sortedMap.put(entry.getKey(), entry.getValue());
    }
    return sortedMap;
}

From source file:MyComparator.java

public static Map<String, Integer> sortByComparator(Map<String, Integer> unsortMap) {

    List<Entry<String, Integer>> list = new LinkedList<Entry<String, Integer>>(unsortMap.entrySet());

    Collections.sort(list, new MyComparator());

    Map<String, Integer> sortedMap = new LinkedHashMap<String, Integer>();
    for (Entry<String, Integer> entry : list) {
        sortedMap.put(entry.getKey(), entry.getValue());
    }/*w w w  . j  ava 2 s.c  o  m*/
    return sortedMap;
}