ariba.util.core
Class InternCharToString

java.lang.Object
  java.util.AbstractMap<K,V>
      ariba.util.core.GrowOnlyHashtable
          ariba.util.core.InternCharToString

All Implemented Interfaces:

java.util.Map

public class InternCharToString
extends GrowOnlyHashtable

This class implements an instance of a GrowOnlyHashtable with the following properties: -- implements a version of intern() that does not have the small size limitations of the native intern() methods on at least hp and nt. -- unlike all current implementations of intern, it does not require any synchronization for the usual case of a get() -- exposes methods to intern a string and "intern" a char[] and retrieve a string. -- exposes a method to calculate the hashCode of a char[] as though it were a string. (there is a varient for the sun and the standard implementations of hashCode() The code dynamically determines which to use) This could be modified to allow a subrange of a char[] to be interned. Typically the static methods should be used, which will intern the strings to a single shared table. Only create a new instance of this class if for some reason you want a separate pool of strings.

Nested Class Summary

Nested classes/interfaces inherited from class ariba.util.core.GrowOnlyHashtable

GrowOnlyHashtable.IdentityMap<K,V>

Nested classes/interfaces inherited from class java.util.AbstractMap

java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Field Summary

Fields inherited from class ariba.util.core.GrowOnlyHashtable

ClassName

Constructor Summary

InternCharToString(int initialCapacity)
Constructs an InternCharToString hashtable capable of holding at least initialCapacity elements before needing to grow.

Method Summary

static int	hashCodeForChars(char[] val) Private method that calculates the hash code for the char[] val using the appropriate hash function.
static java.lang.String	intern(char[] chars) Public method that interns the specified char[] chars.
static java.lang.String	intern(java.lang.String s) Public method that interns the specified String s.
java.lang.String	internUnshared(char[] chars) Public method that interns the specified char[] chars.
java.lang.String	internUnshared(java.lang.String s) Public method that interns the specified String s.
static int	jdk12HashCode(java.lang.String s)
static void	main(java.lang.String[] args)

Methods inherited from class ariba.util.core.GrowOnlyHashtable

capacity, contains, containsKey, count, elementsArray, entrySet, get, isEmpty, keysArray, keysList, put, size, toString

Methods inherited from class java.util.AbstractMap

clear, containsValue, equals, hashCode, keySet, putAll, remove, values

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

InternCharToString

public InternCharToString(int initialCapacity)

Constructs an InternCharToString hashtable capable of holding at least initialCapacity elements before needing to grow. It also determines which is the correct hash function to use from the two standards. Most uses of this class should just call the static intern methods, which will make use of a single, shared table of strings. Only use this constructor if you want to make a separate pool of objects for some unusual reason.

Method Detail

jdk12HashCode

public static final int jdk12HashCode(java.lang.String s)

hashCodeForChars

public static final int hashCodeForChars(char[] val)

Private method that calculates the hash code for the char[] val using the appropriate hash function. Love those standards)

intern

public static java.lang.String intern(java.lang.String s)

Public method that interns the specified String s. This will not provide objects that compare pointer equals with the native String.intern() method as that method is too slow and can not accomidate moderate numbers of interned strings.

intern

public static java.lang.String intern(char[] chars)

Public method that interns the specified char[] chars. This method is identical to the previous method which uses a String as an argument, except that it does not require the caller to construct a temporary String for lookup.

internUnshared

public java.lang.String internUnshared(java.lang.String s)

Public method that interns the specified String s. This will not provide objects that compare pointer equals with the native String.intern() method as that method is too slow and can not accomidate moderate numbers of interned strings.

internUnshared

public java.lang.String internUnshared(char[] chars)

Public method that interns the specified char[] chars. This method is identical to the previous method which uses a String as an argument, except that it does not require the caller to construct a temporary String for lookup.

main

public static void main(java.lang.String[] args)