org.limewire.collection
Class FixedsizeHashMap<K,V>

java.lang.Object
  org.limewire.collection.FixedsizeHashMap<K,V>

public class FixedsizeHashMap<K,V>
extends java.lang.Object

Implements a fixed size HashMap. If FixedsizeHashMap gets full, no new entry can be inserted into it, except by removing an entry first. An attempt to add new entry throws a NoMoreStorageException.

    try{

        FixedsizeHashMap<String, String> fhm = new FixedsizeHashMap<String, String>(3);
        fhm.put("myKey1", "Abby");
        fhm.put("myKey2", "Bob");
        fhm.put("myKey3", "Chris");
        System.out.println(fhm);    

        String ret;
        ret = fhm.put("myKey3", "replace");
        if(ret != null)
            System.out.println("put returned: " + ret);
        System.out.println(fhm);    

        fhm.put("myKey4", "Dan");
    } catch (Exception e) {
        System.out.println("Exception because of maximum size upon put myKey4 ... " + e.toString() );
    }   

    Output:
        {myKey2=Bob, myKey3=Chris, myKey1=Abby}
        put returned: Chris
        {myKey2=Bob, myKey3=replace, myKey1=Abby}
        Exception because of maximum size upon put myKey4 ... org.limewire.collection.NoMoreStorageException

Constructor Summary

FixedsizeHashMap(int size)
Create a new hashMap that stores only the specified number of entries.

Method Summary

void	clear() Clears all entries from the map.
V	get(K key) Returns the value mapped to the given key.
V	put(K key, V value) Maps the given key to the given value.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

FixedsizeHashMap

public FixedsizeHashMap(int size)

Create a new hashMap that stores only the specified number of entries.

Parameters:

size - the number of entries to hold

Throws:

java.lang.IllegalArgumentException - if size is less < 1.

Method Detail

put

public V put(K key,
             V value)
      throws NoMoreStorageException

Maps the given key to the given value. If adding the key would make this contain more elements than the size given at construction, the passed entry is not stored and NoMoreStorageException gets thrown.

Throws:

NoMoreStorageException - when no more space left in the storage ideally, before calling put method, it should be checked whether the map is already full or not

get

public V get(K key)

Returns the value mapped to the given key.

Parameters:

key - the given key

Returns:

the value given key maps to

clear

public void clear()

Clears all entries from the map.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

the string representation of the mappings