Generic hashmap with String as key and Integer as value

      
/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

import java.util.*;

public class Freq {
    public static void main(String[] args) {
        Map<String, Integer> m = new HashMap<String, Integer>();

        // Initialize frequency table from command line
        for (String a : args) {
            Integer freq = m.get(a);
            m.put(a, (freq == null) ? 1 : freq + 1);
        }

        System.out.println(m.size() + " distinct words:");
        System.out.println(m);
    }
}

Related examples in the same category

1.	Iterate through the values of Java HashMap example
2.	Get Synchronized Map from Java HashMap example
3.	Check if a particular key exists in Java HashMap example
4.	Check if a particular value exists in Java HashMap example
5.	Get Set view of Keys from Java HashMap example
6.	Get Size of Java HashMap
7.	Remove all values from Java HashMap example
8.	Remove value from Java HashMap
9.	Create Java Hashtable from HashMap
10.	Sort an HashMap based on the keys
11.	For keys of a map
12.	For values of a map
13.	For both the keys and values of a map
14.	Storing Primitive Types in a Collection
15.	Creating a Copy of a Collection: the objects are not cloned.
16.	Use Iterator to loop through the map key set
17.	Get key set and value set from map and use Iterator to loop through them
18.	Clones a map
19.	Hash map for counting references to Object keys.
20.	Extended Version of java.util.HashMap that provides an extended get method accpeting a default value.
21.	Compact HashMap
22.	This class wraps a HashMap and provides methods by which key objects can be associated with "counting" values.
23.	This extension of HashMap support duplicate keys
24.	Concurrent Hopscotch HashMap

Generic hashmap with String as key and Integer as value : HashMap « Collections Data Structure « Java

Related examples in the same category