com.hp.util

Class StringPool

java.lang.Object

com.hp.util.StringPool

public final class StringPool
extends Object

This class canonicalizes strings. Using a string pool can be helpful in reducing the amount of memory used when there are many references to the same few string values.

A string pool instance is initialized with a "limit" parameter at construction. For a string pool strPool with a limit of N, and two strings S1 and S2; strPool.get(S1) and strPool.get(S2) are guaranteed to return a reference to the same string instance iff S1.equals(S2) && S1.length() <= N.

Using StringPool is preferrable to using String.intern(), which stores strings in its internal cache permanently. StringPool implements a mechanism to "age-out" entries over time.

(NOTE: the age-out mechanism hasn't been implemented yet, but it will be soon!)

Author:

Simon Hunt

Constructor Summary

Constructors

Constructor and Description
StringPool() Constructs a string pool with the default string length limit of 64.
StringPool(int limit) Constructs a string pool with the specified string length limit.

Method Summary

Methods

Modifier and Type	Method and Description
String	get(String s) Returns the canonicalized string from the pool, as long as the length of the string is less than the configured limit for this string pool.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

StringPool

public StringPool()

Constructs a string pool with the default string length limit of 64.

StringPool

public StringPool(int limit)

Constructs a string pool with the specified string length limit. Only strings of length limit or less will be canonicalized.

Parameters:

limit - the string length limit

Method Detail

get

public String get(String s)

Returns the canonicalized string from the pool, as long as the length of the string is less than the configured limit for this string pool. The string is simply returned as is, if it is longer than the limit.

Parameters:

s - the string

Returns:

the canonicalized string

toString

public String toString()

Overrides:

toString in class Object