Package org.apache.lucene.search.suggest.jaspell

Class JaspellTernarySearchTrie

java.lang.Object
org.apache.lucene.search.suggest.jaspell.JaspellTernarySearchTrie
All Implemented Interfaces:
Accountable
@Deprecated public class JaspellTernarySearchTrie extends Object implements Accountable
Deprecated.
Migrate to one of the newer suggesters which are much more RAM efficient.
Implementation of a Ternary Search Trie, a data structure for storing String objects that combines the compact size of a binary search tree with the speed of a digital search trie, and is therefore ideal for practical use in sorting and searching data.

This data structure is faster than hashing for many typical search problems, and supports a broader range of useful problems and operations. Ternary searches are faster than hashing and more powerful, too.

The theory of ternary search trees was described at a symposium in 1997 (see "Fast Algorithms for Sorting and Searching Strings," by J.L. Bentley and R. Sedgewick, Proceedings of the 8th Annual ACM-SIAM Symposium on Discrete Algorithms, January 1997). Algorithms in C, Third Edition, by Robert Sedgewick (Addison-Wesley, 1998) provides yet another view of ternary search trees.

  • Field Details

    • defaultNumReturnValues

      private int defaultNumReturnValues
      Deprecated.
      The default number of values returned by the matchAlmost method.

    • matchAlmostDiff

      private int matchAlmostDiff
      Deprecated.
      the number of differences allowed in a call to the matchAlmostKey method.

    • rootNode

      private JaspellTernarySearchTrie.TSTNode rootNode
      Deprecated.
      The base node in the trie.

    • locale

      private final Locale locale
      Deprecated.

  • Constructor Details

    • JaspellTernarySearchTrie

      public JaspellTernarySearchTrie()
      Deprecated.
      Constructs an empty Ternary Search Trie.

    • JaspellTernarySearchTrie

      public JaspellTernarySearchTrie(Locale locale)
      Deprecated.
      Constructs an empty Ternary Search Trie, specifying the Locale used for lowercasing.

    • JaspellTernarySearchTrie

      public JaspellTernarySearchTrie(Path file) throws IOException
      Deprecated.
      Constructs a Ternary Search Trie and loads data from a Path into the Trie. The file is a normal text document, where each line is of the form word TAB float.
      Parameters:
      file - The Path with the data to load into the Trie.
      Throws:
      IOException - A problem occurred while reading the data.

    • JaspellTernarySearchTrie

      public JaspellTernarySearchTrie(Path file, boolean compression) throws IOException
      Deprecated.
      Constructs a Ternary Search Trie and loads data from a File into the Trie. The file is a normal text document, where each line is of the form "word TAB float".
      Parameters:
      file - The File with the data to load into the Trie.
      compression - If true, the file is compressed with the GZIP algorithm, and if false, the file is a normal text document.
      Throws:
      IOException - A problem occurred while reading the data.

  • Method Details

    • compareCharsAlphabetically

      private static int compareCharsAlphabetically(char cCompare2, char cRef)
      Deprecated.
      Compares characters by alphabetical order.
      Parameters:
      cCompare2 - The first char in the comparison.
      cRef - The second char in the comparison.
      Returns:
      A negative number, 0 or a positive number if the second char is less, equal or greater.

    • setRoot

      void setRoot(JaspellTernarySearchTrie.TSTNode newRoot)
      Deprecated.

    • getRoot

      JaspellTernarySearchTrie.TSTNode getRoot()
      Deprecated.

    • deleteNode

      private void deleteNode(JaspellTernarySearchTrie.TSTNode nodeToDelete)
      Deprecated.
      Deletes the node passed in as an argument. If this node has non-null data, then both the node and the data will be deleted. It also deletes any other nodes in the trie that are no longer needed after the deletion of the node.
      Parameters:
      nodeToDelete - The node to delete.

    • deleteNodeRecursion

      private JaspellTernarySearchTrie.TSTNode deleteNodeRecursion(JaspellTernarySearchTrie.TSTNode currentNode)
      Deprecated.
      Recursively visits each node to be deleted. To delete a node, first set its data to null, then pass it into this method, then pass the node returned by this method into this method (make sure you don't delete the data of any of the nodes returned from this method!) and continue in this fashion until the node returned by this method is null. The TSTNode instance returned by this method will be next node to be operated on by deleteNodeRecursion (This emulates recursive method call while avoiding the JVM overhead normally associated with a recursive method.)
      Parameters:
      currentNode - The node to delete.
      Returns:
      The next node to be called in deleteNodeRecursion.

    • get

      public Object get(CharSequence key)
      Deprecated.
      Retrieve the object indexed by a key.
      Parameters:
      key - A String index.
      Returns:
      The object retrieved from the Ternary Search Trie.

    • getAndIncrement

      public Float getAndIncrement(String key)
      Deprecated.
      Retrieve the Float indexed by key, increment it by one unit and store the new Float.
      Parameters:
      key - A String index.
      Returns:
      The Float retrieved from the Ternary Search Trie.

    • getKey

      protected String getKey(JaspellTernarySearchTrie.TSTNode node)
      Deprecated.
      Returns the key that indexes the node argument.
      Parameters:
      node - The node whose index is to be calculated.
      Returns:
      The String that indexes the node argument.

    • getNode

      public JaspellTernarySearchTrie.TSTNode getNode(CharSequence key)
      Deprecated.
      Returns the node indexed by key, or null if that node doesn't exist. Search begins at root node.
      Parameters:
      key - A String that indexes the node that is returned.
      Returns:
      The node object indexed by key. This object is an instance of an inner class named TernarySearchTrie.TSTNode.

    • getNode

      protected JaspellTernarySearchTrie.TSTNode getNode(CharSequence key, JaspellTernarySearchTrie.TSTNode startNode)
      Deprecated.
      Returns the node indexed by key, or null if that node doesn't exist. The search begins at root node.
      Parameters:
      key - A String that indexes the node that is returned.
      startNode - The top node defining the subtrie to be searched.
      Returns:
      The node object indexed by key. This object is an instance of an inner class named TernarySearchTrie.TSTNode.

    • getOrCreateNode

      protected JaspellTernarySearchTrie.TSTNode getOrCreateNode(CharSequence key) throws NullPointerException, IllegalArgumentException
      Deprecated.
      Returns the node indexed by key, creating that node if it doesn't exist, and creating any required intermediate nodes if they don't exist.
      Parameters:
      key - A String that indexes the node that is returned.
      Returns:
      The node object indexed by key. This object is an instance of an inner class named TernarySearchTrie.TSTNode.
      Throws:
      NullPointerException - If the key is null.
      IllegalArgumentException - If the key is an empty String.

    • matchAlmost

      public List<String> matchAlmost(String key)
      Deprecated.
      Returns a List of keys that almost match the argument key. Keys returned will have exactly diff characters that do not match the target key, where diff is equal to the last value passed in as an argument to the setMatchAlmostDiff method.

      If the matchAlmost method is called before the setMatchAlmostDiff method has been called for the first time, then diff = 0.

      Parameters:
      key - The target key.
      Returns:
      A List with the results.

    • matchAlmost

      public List<String> matchAlmost(CharSequence key, int numReturnValues)
      Deprecated.
      Returns a List of keys that almost match the argument key. Keys returned will have exactly diff characters that do not match the target key, where diff is equal to the last value passed in as an argument to the setMatchAlmostDiff method.

      If the matchAlmost method is called before the setMatchAlmostDiff method has been called for the first time, then diff = 0.

      Parameters:
      key - The target key.
      numReturnValues - The maximum number of values returned by this method.
      Returns:
      A List with the results

    • matchAlmostRecursion

      private List<String> matchAlmostRecursion(JaspellTernarySearchTrie.TSTNode currentNode, int charIndex, int d, CharSequence matchAlmostKey, int matchAlmostNumReturnValues, List<String> matchAlmostResult2, boolean upTo)
      Deprecated.
      Recursivelly vists the nodes in order to find the ones that almost match a given key.
      Parameters:
      currentNode - The current node.
      charIndex - The current char.
      d - The number of differences so far.
      matchAlmostKey - The key being searched.
      matchAlmostNumReturnValues - The maximum number of values in the result List.
      matchAlmostResult2 - The results so far.
      upTo - If true all keys having up to and including matchAlmostDiff mismatched letters will be included in the result (including a key that is exactly the same as the target string) otherwise keys will be included in the result only if they have exactly matchAlmostDiff number of mismatched letters.
      Returns:
      A List with the results.

    • matchPrefix

      public List<String> matchPrefix(String prefix)
      Deprecated.
      Returns an alphabetical List of all keys in the trie that begin with a given prefix. Only keys for nodes having non-null data are included in the List.
      Parameters:
      prefix - Each key returned from this method will begin with the characters in prefix.
      Returns:
      A List with the results.

    • matchPrefix

      public List<String> matchPrefix(CharSequence prefix, int numReturnValues)
      Deprecated.
      Returns an alphabetical List of all keys in the trie that begin with a given prefix. Only keys for nodes having non-null data are included in the List.
      Parameters:
      prefix - Each key returned from this method will begin with the characters in prefix.
      numReturnValues - The maximum number of values returned from this method.
      Returns:
      A List with the results

    • numDataNodes

      public int numDataNodes()
      Deprecated.
      Returns the number of nodes in the trie that have non-null data.
      Returns:
      The number of nodes in the trie that have non-null data.

    • numDataNodes

      protected int numDataNodes(JaspellTernarySearchTrie.TSTNode startingNode)
      Deprecated.
      Returns the number of nodes in the subtrie below and including the starting node. The method counts only nodes that have non-null data.
      Parameters:
      startingNode - The top node of the subtrie. the node that defines the subtrie.
      Returns:
      The total number of nodes in the subtrie.

    • numNodes

      public int numNodes()
      Deprecated.
      Returns the total number of nodes in the trie. The method counts nodes whether or not they have data.
      Returns:
      The total number of nodes in the trie.

    • numNodes

      protected int numNodes(JaspellTernarySearchTrie.TSTNode startingNode)
      Deprecated.
      Returns the total number of nodes in the subtrie below and including the starting Node. The method counts nodes whether or not they have data.
      Parameters:
      startingNode - The top node of the subtrie. The node that defines the subtrie.
      Returns:
      The total number of nodes in the subtrie.

    • put

      public void put(CharSequence key, Object value)
      Deprecated.
      Stores a value in the trie. The value may be retrieved using the key.
      Parameters:
      key - A String that indexes the object to be stored.
      value - The object to be stored in the Trie.

    • recursiveNodeCalculator

      private int recursiveNodeCalculator(JaspellTernarySearchTrie.TSTNode currentNode, boolean checkData, int numNodes2)
      Deprecated.
      Recursivelly visists each node to calculate the number of nodes.
      Parameters:
      currentNode - The current node.
      checkData - If true we check the data to be different of null.
      numNodes2 - The number of nodes so far.
      Returns:
      The number of nodes accounted.

    • remove

      public void remove(String key)
      Deprecated.
      Removes the value indexed by key. Also removes all nodes that are rendered unnecessary by the removal of this data.
      Parameters:
      key - A string that indexes the object to be removed from the Trie.

    • setMatchAlmostDiff

      public void setMatchAlmostDiff(int diff)
      Deprecated.
      Sets the number of characters by which words can differ from target word when calling the matchAlmost method.

      Arguments less than 0 will set the char difference to 0, and arguments greater than 3 will set the char difference to 3.

      Parameters:
      diff - The number of characters by which words can differ from target word.

    • setNumReturnValues

      public void setNumReturnValues(int num)
      Deprecated.
      Sets the default maximum number of values returned from the matchPrefix and matchAlmost methods.

      The value should be set this to -1 to get an unlimited number of return values. note that the methods mentioned above provide overloaded versions that allow you to specify the maximum number of return values, in which case this value is temporarily overridden.

      Parameters:
      num - The number of values that will be returned when calling the methods above.

    • sortKeys

      protected List<String> sortKeys(JaspellTernarySearchTrie.TSTNode startNode, int numReturnValues)
      Deprecated.
      Returns keys sorted in alphabetical order. This includes the start Node and all nodes connected to the start Node.

      The number of keys returned is limited to numReturnValues. To get a list that isn't limited in size, set numReturnValues to -1.

      Parameters:
      startNode - The top node defining the subtrie to be searched.
      numReturnValues - The maximum number of values returned from this method.
      Returns:
      A List with the results.

    • sortKeysRecursion

      private List<String> sortKeysRecursion(JaspellTernarySearchTrie.TSTNode currentNode, int sortKeysNumReturnValues, List<String> sortKeysResult2)
      Deprecated.
      Returns keys sorted in alphabetical order. This includes the current Node and all nodes connected to the current Node.

      Sorted keys will be appended to the end of the resulting List. The result may be empty when this method is invoked, but may not be null.

      Parameters:
      currentNode - The current node.
      sortKeysNumReturnValues - The maximum number of values in the result.
      sortKeysResult2 - The results so far.
      Returns:
      A List with the results.

    • ramBytesUsed

      public long ramBytesUsed()
      Deprecated.
      Description copied from interface: Accountable
      Return the memory usage of this object in bytes. Negative values are illegal.
      Specified by:
      ramBytesUsed in interface Accountable