org.apache.commons.collections4.trie.analyzer

Class StringKeyAnalyzer

java.lang.Object

org.apache.commons.collections4.trie.KeyAnalyzer<java.lang.String>

org.apache.commons.collections4.trie.analyzer.StringKeyAnalyzer

All Implemented Interfaces:

java.io.Serializable, java.util.Comparator<java.lang.String>

public class StringKeyAnalyzer
extends KeyAnalyzer<java.lang.String>

An KeyAnalyzer for Strings.

Since:

4.0

Version:

$Id: StringKeyAnalyzer.java 1543168 2013-11-18 21:22:43Z ggregory $

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static StringKeyAnalyzer	INSTANCE A singleton instance of StringKeyAnalyzer.
static int	LENGTH The number of bits per Character.
private static int	MSB A bit mask where the first bit is 1 and the others are zero.
private static long	serialVersionUID

Fields inherited from class org.apache.commons.collections4.trie.KeyAnalyzer

EQUAL_BIT_KEY, NULL_BIT_KEY, OUT_OF_BOUNDS_BIT_KEY

Constructor Summary

Constructors

Constructor and Description
StringKeyAnalyzer()

Method Summary

Modifier and Type	Method and Description
int	bitIndex(java.lang.String key, int offsetInBits, int lengthInBits, java.lang.String other, int otherOffsetInBits, int otherLengthInBits) Returns the n-th different bit between key and other.
int	bitsPerElement() Returns the number of bits per element in the key.
boolean	isBitSet(java.lang.String key, int bitIndex, int lengthInBits) Returns whether or not a bit is set.
boolean	isPrefix(java.lang.String prefix, int offsetInBits, int lengthInBits, java.lang.String key) Determines whether or not the given prefix (from offset to length) is a prefix of the given key.
int	lengthInBits(java.lang.String key) Returns the length of the Key in bits.
private static int	mask(int bit) Returns a bit mask where the given bit is set.

Methods inherited from class org.apache.commons.collections4.trie.KeyAnalyzer

compare

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

INSTANCE

public static final StringKeyAnalyzer INSTANCE

A singleton instance of StringKeyAnalyzer.

LENGTH

public static final int LENGTH

The number of bits per Character.

See Also:

Constant Field Values

MSB

private static final int MSB

A bit mask where the first bit is 1 and the others are zero.

See Also:

Constant Field Values

Constructor Detail

StringKeyAnalyzer

public StringKeyAnalyzer()

Method Detail

mask

private static int mask(int bit)

Returns a bit mask where the given bit is set.

bitsPerElement

public int bitsPerElement()

Description copied from class: KeyAnalyzer

Returns the number of bits per element in the key. This is only useful for variable-length keys, such as Strings.

Specified by:

bitsPerElement in class KeyAnalyzer<java.lang.String>

Returns:

the number of bits per element

lengthInBits

public int lengthInBits(java.lang.String key)

Description copied from class: KeyAnalyzer

Returns the length of the Key in bits.

Specified by:

lengthInBits in class KeyAnalyzer<java.lang.String>

Parameters:

key - the key

Returns:

the bit length of the key

bitIndex

public int bitIndex(java.lang.String key,
                    int offsetInBits,
                    int lengthInBits,
                    java.lang.String other,
                    int otherOffsetInBits,
                    int otherLengthInBits)

Description copied from class: KeyAnalyzer

Returns the n-th different bit between key and other. This starts the comparison in key at 'offsetInBits' and goes for 'lengthInBits' bits, and compares to the other key starting at 'otherOffsetInBits' and going for 'otherLengthInBits' bits.

Specified by:

bitIndex in class KeyAnalyzer<java.lang.String>

Parameters:

key - the key to use

offsetInBits - the bit offset in the key

lengthInBits - the maximum key length in bits to use

other - the other key to use

otherOffsetInBits - the bit offset in the other key

otherLengthInBits - the maximum key length in bits for the other key

Returns:

the bit index where the key and other first differ

isBitSet

public boolean isBitSet(java.lang.String key,
                        int bitIndex,
                        int lengthInBits)

Description copied from class: KeyAnalyzer

Returns whether or not a bit is set.

Specified by:

isBitSet in class KeyAnalyzer<java.lang.String>

Parameters:

key - the key to check, may not be null

bitIndex - the bit index to check

lengthInBits - the maximum key length in bits to check

Returns:

true if the bit is set in the given key and bitIndex < lengthInBits, false otherwise.

isPrefix

public boolean isPrefix(java.lang.String prefix,
                        int offsetInBits,
                        int lengthInBits,
                        java.lang.String key)

Description copied from class: KeyAnalyzer

Determines whether or not the given prefix (from offset to length) is a prefix of the given key.

Specified by:

isPrefix in class KeyAnalyzer<java.lang.String>

Parameters:

prefix - the prefix to check

offsetInBits - the bit offset in the key

lengthInBits - the maximum key length in bits to use

key - the key to check

Returns:

true if this is a valid prefix for the given key