Example usage for java.util Comparator Comparator

Introduction

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

Prototype

Comparator

Source Link

Usage

From source file:Main.java

public static String getKeyFromParams(List<NameValuePair> nameValuePairs, String publishId) {
    Collections.sort(nameValuePairs, new Comparator<NameValuePair>() {
        @Override/*from  ww w . j ava  2s  .  c  om*/
        public int compare(NameValuePair p1, NameValuePair p2) {
            return p1.getName().compareTo(p2.getName());
        }
    });

    StringBuilder keyBuilder = new StringBuilder();
    boolean isFirst = true;
    for (NameValuePair nvp : nameValuePairs) {
        if (!isFirst) {
            keyBuilder.append("&");
        }
        keyBuilder.append(nvp.getName()).append("=").append(nvp.getValue());
        isFirst = false;
    }

    keyBuilder.append("&").append(publishId);

    String key = keyBuilder.toString();
    byte[] keyBytes = getBytes(key);
    return getMd5Digest(new String(Base64.encode(keyBytes, Base64.NO_WRAP)));
}

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  ww  .  ja  v a  2  s  . c  o  m*/

    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  ww w .j  ava  2  s.c  om*/
                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 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//  ww w. j a  v a2s  .  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

@SuppressWarnings({ "unchecked", "rawtypes" })
public static List<Set<Entry<String, Object>>> sortMapByKey(Map<String, ? extends Object> map) {
    if (map == null) {
        return null;
    }//ww  w.j  a  va 2s .  co m
    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 <T> Comparator<T> identityComparator() {
    return new Comparator<T>() {

        @Override//from   w w  w.  j av  a 2  s .c o  m
        public int compare(T o1, T o2) {
            return System.identityHashCode(o1) - System.identityHashCode(o2);
        }
    };
}

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());
        }/*from   w  w  w . j a v a 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

/**
 * sort Map by key desc/*www. j  av a2  s  .c o m*/
 * 
 * @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:Main.java

/**
 * Creates a list of sorted entries by copying them from the entrySet of a
 * map. They are sorted by the natural order of the value (defined by
 * V.compareTo(V))// w w w  .ja  va2s  .  co  m
 * 
 * @param map
 *            the source map
 * 
 * @return a newly created sorted list
 */
public static <K, V extends Comparable<V>> List<Entry<K, V>> orderByValue(Map<K, V> map, final boolean desc) {
    return order(map, new Comparator<Entry<K, V>>() {
        public int compare(Entry<K, V> o1, Entry<K, V> o2) {
            return (desc ? -1 : 1) * o1.getValue().compareTo(o2.getValue());
        }
    });
}

From source file:Main.java

/**
 * Returns the indices that would sort an array.
 * @param array Array.// w  ww  . j a  v a  2  s  .com
 * @param ascending Ascending order.
 * @return Array of indices.
 */
public static int[] Argsort(final double[] array, final boolean ascending) {
    Integer[] indexes = new Integer[array.length];
    for (int i = 0; i < indexes.length; i++) {
        indexes[i] = i;
    }
    Arrays.sort(indexes, new Comparator<Integer>() {
        @Override
        public int compare(final Integer i1, final Integer i2) {
            return (ascending ? 1 : -1) * Double.compare(array[i1], array[i2]);
        }
    });
    return asArray(indexes);
}