Chapter 16
The java.text Package

CollationKey

Name

CollationKey

Synopsis

Class Name:

java.text.CollationKey

Superclass:

java.lang.Object

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

The CollationKey class optimizes the sorting of many strings. The easiest way to compare strings is using Collator.compare(), but this can be inefficient, especially if the same strings are compared many times. Instead, you can create a CollationKey for each of your strings and compare the CollationKey objects to each other using the compareTo() method. A CollationKey is essentially a bit representation of a String object. Two CollationKey objects can be compared bitwise, which allows for a fast comparison.

You cannot create CollationKey objects directly; you must create them through a specific Collator object using Collator.getCollationKey(). You can only compare CollationKey objects that have been generated from the same Collator.

Class Summary

public final class java.text.CollationKey extends java.lang.Object {
  // Instance Methods
  public int compareTo(CollationKey target);
  public boolean equals(Object target); 
  public String getSourceString();
  public int hashCode();
  public byte[] toByteArray();
}

Instance Methods

compareTo

public int compareTo(CollationKey target)

Parameters

target: The key to compare with this CollationKey.

Returns

-1 if this CollationKey is less than target, 0 if this CollationKey is equal to target, or 1 if this CollationKey is greater than target.

Description

This method returns an integer that indicates the ordering of this CollationKey and the given CollationKey. Only CollationKey objects generated by the same Collator should be compared.

equals

public boolean equals(Object target)

Parameters

target: The object to be compared with this object.

Returns

true if the objects are equal; false if they are not.

Overrides

Object.equals()

Description

This method returns true if obj is an instance of CollationKey and is equivalent to this CollationKey.

getSourceString

public String getSourceString()

Returns

The string that generated this CollationKey.

Description

This method returns the string that was passed to Collator.getCollationKey() to create this CollationKey.

hashCode

public int hashCode()

Returns

A hashcode for this object.

Overrides

Object.hashCode()

Description

This method returns a hashcode for this CollationKey.

toByteArray

public byte[] toByteArray()

Returns

A byte array that represents this CollationKey.

Description

This method returns a byte array that represents the value of this CollationKey, with the most significant byte first.

Inherited Methods

Method	Inherited From	Method	Inherited From
`clone()`	`Object`	`finalize()`	`Object`
`getClass()`	`Object`	`notify()`	`Object`
`notifyAll()`	`Object`	`toString()`	`Object`
`wait()`	`Object`	`wait(long)`	`Object`
`wait(long, int)`	`Object`