Package org.passay.dictionary

Class TernaryTreeDictionary

java.lang.Object
org.passay.dictionary.TernaryTreeDictionary
All Implemented Interfaces:
Dictionary
public class TernaryTreeDictionary extends Object implements Dictionary
Provides fast searching for dictionary words using a ternary tree. The entire dictionary is stored in memory, so heap size may need to be adjusted to accommodate large dictionaries. It is highly recommended that sorted word lists be inserted using their median. This helps to produce a balanced ternary tree which improves search time. This class inherits the lower case property of the supplied word list.

  • Field Details

    • tree

      protected final TernaryTree tree
      Ternary tree used for searching.

  • Constructor Details

    • TernaryTreeDictionary

      public TernaryTreeDictionary(WordList wordList)
      Creates a new balanced tree dictionary from the supplied WordList. This constructor creates a balanced tree by inserting from the median of the word list, which may require additional work depending on the WordList implementation.

      NOTE While using an unsorted word list produces correct results, it may dramatically reduce search efficiency. Using a sorted word list is recommended.

      Parameters:
      wordList - list of words used to back the dictionary. This list is used exclusively to initialize the internal TernaryTree used by the dictionary, and may be safely discarded after dictionary creation.

    • TernaryTreeDictionary

      public TernaryTreeDictionary(WordList wordList, boolean useMedian)
      Creates a new dictionary instance from the given WordList.
      Parameters:
      wordList - list of words used to back the dictionary. This list is used exclusively to initialize the internal TernaryTree used by the dictionary, and may be safely discarded after dictionary creation.

      NOTE While using an unsorted word list produces correct results, it may dramatically reduce search efficiency. Using a sorted word list is recommended.

      useMedian - set to true to force creation of a balanced tree by inserting into the tree from the median of the WordList outward. Depending on the word list implementation, this may require additional work to access the median element on each insert.

    • TernaryTreeDictionary

      public TernaryTreeDictionary(TernaryTree tree)
      Creates a dictionary that uses the supplied ternary tree for dictionary searches.
      Parameters:
      tree - ternary tree used to back dictionary.

  • Method Details

    • size

      public long size()
      Description copied from interface: Dictionary
      Returns the number of words in this dictionary
      Specified by:
      size in interface Dictionary
      Returns:
      total number of words to search

    • search

      public boolean search(CharSequence word)
      Description copied from interface: Dictionary
      Returns whether the supplied word exists in the dictionary.
      Specified by:
      search in interface Dictionary
      Parameters:
      word - to search for
      Returns:
      whether word was found

    • partialSearch

      public CharSequence[] partialSearch(CharSequence word)
      Returns an array of strings which partially match the supplied word. This search is case-sensitive by default. See TernaryTree.partialSearch(java.lang.CharSequence).
      Parameters:
      word - to search for
      Returns:
      array of matching words

    • nearSearch

      public CharSequence[] nearSearch(CharSequence word, int distance)
      Returns an array of strings which are near to the supplied word by the supplied distance. This search is case-sensitive by default. See TernaryTree.nearSearch(java.lang.CharSequence, int).
      Parameters:
      word - to search for
      distance - for valid match
      Returns:
      array of matching words

    • getTernaryTree

      public TernaryTree getTernaryTree()
      Returns the underlying ternary tree used by this dictionary.
      Returns:
      ternary tree

    • main

      public static void main(String[] args) throws Exception
      Provides command line access to a ternary tree dictionary.
      Parameters:
      args - command line arguments
      Throws:
      Exception - if an error occurs