Package com.globalmentor.collections

Class CharSequenceSuffixTrees

java.lang.Object

com.globalmentor.collections.CharSequenceSuffixTrees

public class CharSequenceSuffixTrees
extends Object

Utilities for working with suffix trees of sequences of characters.

Author:

Garret Wilson

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CharSequenceSuffixTrees.AbstractCharSequenceVisitor	An abstract implementation of a visitor for character sequences.

Constructor Summary

Constructors

Constructor	Description
CharSequenceSuffixTrees()

Method Summary

Modifier and Type	Method	Description
static CharSequence	getLongestRepeatedSubsequence(CharSequence charSequence)	Determines the longest subsequence that is repeated in the given subsequence.
static CharSequence	getLongestSequentialRepeatedSubsequence(CharSequence charSequence)	Determines the longest subsequence that is repeated in the given subsequence.

Methods inherited from class java.lang.Object

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

Constructor Details

CharSequenceSuffixTrees

public CharSequenceSuffixTrees()

Method Details

getLongestRepeatedSubsequence

public static CharSequence getLongestRepeatedSubsequence(CharSequence charSequence)

Determines the longest subsequence that is repeated in the given subsequence.

This implementation walks the tree and finds the non-leaf node that is farthest in terms of characters from the root of the tree. The repeated subsequence is the sequence of characters from the root to that node.

Parameters:

charSequence - The character sequence to check.

Returns:

The longest repeated subsequence in the given character sequence, or null if no subsequence is repeated.

Throws:

NullPointerException - if the given character sequence is null.

getLongestSequentialRepeatedSubsequence

public static CharSequence getLongestSequentialRepeatedSubsequence(CharSequence charSequence)

Determines the longest subsequence that is repeated in the given subsequence.

This implementation walks the tree and, for every non-leaf node (which indicates a repeated sequence as the sequence of characters from the root to that node), determines if there exists the exact sequence starting with the node just found (which indicates that the repeated sequence is followed by an identical sequence). This process continues until the longest of these sequences is determined.

Parameters:

charSequence - The character sequence to check.

Returns:

The longest repeated subsequence in the given character sequence, or null if no subsequence is repeated.

Throws:

NullPointerException - if the given character sequence is null.