|
java.lang.Object
 java.util.AbstractMap<K,V>
java.util.TreeMap<K,V>
- All Implemented Interfaces:
- Serializable, Cloneable, Map<K,V>, SortedMap<K,V>
- See Also:
- Top Examples, Source Code,
HashMap,
Hashtable,
Comparable,
Comparator,
Collection,
Collections.synchronizedMap(Map)
public void clear() - See Also:
- V, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
[205]Create a structure like a HashMap with case insensitive keys
By Anonymous on 2005/07/08 08:49:16 Rate
//the key in HashMap is case sensitive
//Here is how do you create a structure like a HashMap with case insensitive keys
import java.util.*;
class ComparatorTest implements Comparator {
public int compare ( Object o1, Object o2 ) {
String s1 = ( String ) o1;
String s2 = ( String ) o2;
return s1.toUpperCase ( ) .compareTo ( s2.toUpperCase ( ) ) ;
}
public boolean equals ( Object o ) {
String s = ( String ) o;
return compare ( this, o ) ==0;
}
}
import java.util.*;
public class tm
{
public static void main ( String [ ] args )
{
TreeMap tm = new TreeMap ( new ComparatorTest ( ) ) ;
tm.put ( "soda", "coke" ) ;
tm.put ( "Juice", "orange" ) ;
tm.put ( "SODA", "7-up" ) ;
Set set = tm.entrySet ( ) ;
Iterator iterator = set.iterator ( ) ;
while ( iterator.hasNext ( ) ) {
Map.Entry entry = ( Map.Entry ) iterator.next ( ) ;
System.out.println ( entry.getKey ( ) + "/" + entry.getValue ( ) ) ;
}
}
}
//clear
public Object clone() - See Also:
Cloneable, V, AbstractMap
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public Comparator<? super K> comparator() - See Also:
- SortedMap
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
[1573]Sort a TreeMap by its values not its keys
By Anonymous on 2005/10/15 19:45:12 Rate
//Sort a TreeMap by its values not its keys
1. Create a TreeSet of key/value pairs where the Comparator sorts by
the *value* ( the Double ) in each pair.
2. Get the key/value pairs from the original TreeMap by calling
TreeMap.entrySet ( )
3. Add all the pairs from 2 into the TreeSet in 1.
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
public class SortedValueTest
{
public static void main ( String [ ] args )
{
Map map = new TreeMap ( ) ;
map.put ( "1/2", new Double ( 0.5 ) ) ;
map.put ( "1/4", new Double ( 0.25 ) ) ;
map.put ( "1/8", new Double ( 0.125 ) ) ;
map.put ( "1/16", new Double ( 0.0625 ) ) ;
Set set = new TreeSet (
new Comparator ( )
{
public int compare ( Object o1, Object o2 )
{
Map.Entry e1 = ( Map.Entry ) o1;
Map.Entry e2 = ( Map.Entry ) o2;
Double d1 = ( Double ) e1.getValue ( ) ;
Double d2 = ( Double ) e2.getValue ( ) ;
return d1.compareTo ( d2 ) ;
}
} ) ;
set.addAll ( map.entrySet ( ) ) ;
for ( Iterator iter = set.iterator ( ) ; iter.hasNext ( ) ; )
{
Map.Entry entry = ( Map.Entry ) iter.next ( ) ;
System.out.println ( entry.getKey ( ) + " = " + entry.getValue ( ) ) ;
}
}
}
This will output the following:
1/16 = 0.0625
1/8 = 0.125
1/4 = 0.25
1/2 = 0.5
public boolean containsKey(Object key) - See Also:
- NullPointerException, ClassCastException, V, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public boolean containsValue(Object value) - See Also:
- V, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public Set<Map.Entry<K,V>> entrySet() - See Also:
- AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public K firstKey() - See Also:
- NoSuchElementException, SortedMap
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public V get(Object key) - See Also:
containsKey(Object), NullPointerException, ClassCastException, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap headMap(Object toKey) - See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap<K,V> headMap(K toKey) - See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public Set<K> keySet() - See Also:
- AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
[229]Sorted Map
By Doug Borter dfborter { at } yahoo { dot } com on 2004/04/23 10:32:38 Rate
import java.util.*;
public class tSortedMap {
public static void main ( String [ ] args ) {
Map m = new TreeMap ( ) ;
StringBuffer sb = null;
m.put ( "Barb",new Integer ( 101 ) ) ;
m.put ( "Zeke",new Integer ( 102 ) ) ;
m.put ( "Mary",new Integer ( 110 ) ) ;
m.put ( "Andy",new Integer ( 124 ) ) ;
m.put ( "Pete",new Integer ( 9111130 ) ) ;
for ( Iterator i = m.keySet ( ) .iterator ( ) ; i.hasNext ( ) ; ) {
sb = new StringBuffer ( ( String ) i.next ( ) ) ;
System.out.println ( sb + " " + m.get ( sb.toString ( ) ) ) ;
}
}
}
public K lastKey() - See Also:
- NoSuchElementException, SortedMap
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public Object put(Object key,
Object value)- See Also:
- NullPointerException, ClassCastException, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public V put(K key,
V value)- See Also:
- NullPointerException, ClassCastException, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public void putAll(Map<? extends K,? extends V> map) - See Also:
- NullPointerException, ClassCastException, AbstractMap
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public V remove(Object key) - See Also:
- NullPointerException, ClassCastException, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public int size() - See Also:
- V, AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap subMap(Object fromKey,
Object toKey)- See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap<K,V> subMap(K fromKey,
K toKey)- See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap tailMap(Object fromKey) - See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public SortedMap<K,V> tailMap(K fromKey) - See Also:
- NullPointerException, IllegalArgumentException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public TreeMap() - See Also:
Comparable
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public TreeMap(Comparator<? super K> c) - Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public TreeMap(Map<? extends K,? extends V> m) - See Also:
- NullPointerException, ClassCastException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
[1792]HashMap to TreeMap
By Anonymous on 2006/07/25 07:47:21 Rate
The popular implementations of Map are java.util.HashMap and java.util.TreeMap. The HashMap facilitates easy insertion, deletion, and retrieval of elements. On the other hand, TreeMap is a neat alternative to traverse the keys of a map in a sorted order.
import java.util.*;
public class MapDemo {
private HashMap hashMap;
private TreeMap treeMap;
public void startDemo ( ) {
// Initialize the hash map
hashMap = new HashMap ( ) ;
hashMap.put ( ???Key2???, ???2??? ) ;
hashMap.put ( ???Key4???, ???4??? ) ;
hashMap.put ( ???Key1???, ???1??? ) ;
hashMap.put ( ???Key3???, ???3??? ) ;
// Sort the hash map using a tree map
treeMap = new TreeMap ( hashMap ) ;
}
public static void main ( String [ ] args ) {
MapDemo md = new MapDemo ( ) ;
md.startDemo ( ) ;
// Print maps
System.out.println ( ???HashMap: ??? + md.hashMap ) ;
System.out.println ( ???TreeMap: ??? + md.treeMap ) ;
}
}
Following is the output,
HashMap: { Key4=4, Key3=3, Key2=2, Key1=1 }
TreeMap: { Key1=1, Key2=2, Key3=3, Key4=4 }
public TreeMap(SortedMap<K,? extends V> m) - See Also:
- NullPointerException
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
public Collection<V> values() - See Also:
- AbstractMap, Map
- Geek's Notes:
- Description Add your codes or notes Search More Java Examples
|
Popular Tags |
Java API By Example, From Geeks To Geeks.