org.apache.nutch.util

Class TrieStringMatcher

java.lang.Object

org.apache.nutch.util.TrieStringMatcher

Direct Known Subclasses:

PrefixStringMatcher, SuffixStringMatcher

public abstract class TrieStringMatcher
extends Object

TrieStringMatcher is a base class for simple tree-based string matching.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	TrieStringMatcher.TrieNode Node class for the character tree.

Field Summary

Fields

Modifier and Type	Field and Description
protected TrieStringMatcher.TrieNode	root

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TrieStringMatcher()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addPatternBackward(String s) Adds any necessary nodes to the trie so that the given String can be decoded in reverse and the first character is represented by a terminal node.
protected void	addPatternForward(String s) Adds any necessary nodes to the trie so that the given String can be decoded and the last character is represented by a terminal node.
abstract String	longestMatch(String input) Returns the longest substring of input that is matched by a pattern in the trie, or null if no match exists.
protected TrieStringMatcher.TrieNode	matchChar(TrieStringMatcher.TrieNode node, String s, int idx) Returns the next TrieStringMatcher.TrieNode visited, given that you are at node, and the the next character in the input is the idx'th character of s.
abstract boolean	matches(String input) Returns true if the given String is matched by a pattern in the trie
abstract String	shortestMatch(String input) Returns the shortest substring of input that is matched by a pattern in the trie, or null if no match exists.

Methods inherited from class java.lang.Object

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

Field Detail

root

protected TrieStringMatcher.TrieNode root

Constructor Detail

TrieStringMatcher

protected TrieStringMatcher()

Method Detail

matchChar

protected final TrieStringMatcher.TrieNode matchChar(TrieStringMatcher.TrieNode node,
                                   String s,
                                   int idx)

Returns the next TrieStringMatcher.TrieNode visited, given that you are at node, and the the next character in the input is the idx'th character of s.

addPatternForward

protected final void addPatternForward(String s)

Adds any necessary nodes to the trie so that the given String can be decoded and the last character is represented by a terminal node. Zero-length Strings are ignored.

addPatternBackward

protected final void addPatternBackward(String s)

Adds any necessary nodes to the trie so that the given String can be decoded in reverse and the first character is represented by a terminal node. Zero-length Strings are ignored.

matches

public abstract boolean matches(String input)

Returns true if the given String is matched by a pattern in the trie

shortestMatch

public abstract String shortestMatch(String input)

Returns the shortest substring of input that is matched by a pattern in the trie, or null if no match exists.

longestMatch

public abstract String longestMatch(String input)

Returns the longest substring of input that is matched by a pattern in the trie, or null if no match exists.