Package opennlp.tools.ngram

# Class NGramModel

java.lang.Object
opennlp.tools.ngram.NGramModel

All Implemented Interfaces:
  `Iterable<StringList>`

Direct Known Subclasses:
  `NGramLanguageModel`

public class NGramModel extends Object implements Iterable<StringList>
The `NGramModel` can be used to crate ngrams and character ngrams.

See Also:
  - `StringList`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `NGramModel()`
  Instantiates an empty `NGramModel` instance.
  `NGramModel(InputStream in)`
  Instantiates a `NGramModel` via an `InputStream` reference.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `add(CharSequence chars, int minLength, int maxLength)`
  Adds character NGrams to the current instance.
  `void`
  `add(StringList ngram)`
  Adds one NGram, if it already exists the count increase by one.
  `void`
  `add(StringList ngram, int minLength, int maxLength)`
  Adds NGrams up to the specified length to the current instance.
  `boolean`
  `contains(StringList tokens)`
  Checks fit he given tokens are contained by the current instance.
  `void`
  `cutoff(int cutoffUnder, int cutoffOver)`
  Deletes all ngram which do appear less than the cutoffUnder value and more often than the cutoffOver value.
  `boolean`
  `equals(Object obj)`
  `int`
  `getCount(StringList ngram)`
  Retrieves the count of the given ngram.
  `int`
  `hashCode()`
  `Iterator<StringList>`
  `iterator()`
  Retrieves an `Iterator` over all `StringList` entries.
  `int`
  `numberOfGrams()`
  Retrieves the total count of all Ngrams.
  `void`
  `remove(StringList tokens)`
  Removes the specified tokens form the NGram model, they are just dropped.
  `void`
  `serialize(OutputStream out)`
  Writes the ngram instance to the given `OutputStream`.
  `void`
  `setCount(StringList ngram, int count)`
  Sets the count of an existing ngram.
  `int`
  `size()`
  Retrieves the number of `StringList` entries in the current instance.
  `Dictionary`
  `toDictionary()`
  Creates a dictionary which contain all `StringList` which are in the current `NGramModel`.
  `Dictionary`
  `toDictionary(boolean caseSensitive)`
  Creates a dictionary which contains all `StringList`s which are in the current `NGramModel`.
  `String`
  `toString()`

  ### Methods inherited from class java.lang.Object

  `getClass, notify, notifyAll, wait, wait, wait`

  ### Methods inherited from interface java.lang.Iterable

  `forEach, spliterator`

- ## Constructor Details

  - ### NGramModel

    public NGramModel()
    Instantiates an empty `NGramModel` instance.

  - ### NGramModel

    public NGramModel(InputStream in) throws IOException
    Instantiates a `NGramModel` via an `InputStream` reference.
    Parameters:
      `in` - the serialized model stream
    Throws:
      `IOException` - Thrown if errors occurred reading from `in`.

- ## Method Details

  - ### getCount

    public int getCount(StringList ngram)
    Retrieves the count of the given ngram.
    Parameters:
      `ngram` - an ngram
    Returns:
      count of the ngram or 0 if it is not contained

  - ### setCount

    public void setCount(StringList ngram, int count)
    Sets the count of an existing ngram.
    Parameters:
      `ngram` -
      `count` -

  - ### add

    public void add(StringList ngram)
    Adds one NGram, if it already exists the count increase by one.
    Parameters:
      `ngram` -

  - ### add

    public void add(StringList ngram, int minLength, int maxLength)
    Adds NGrams up to the specified length to the current instance.
    Parameters:
      `ngram` - the tokens to build the uni-grams, bi-grams, tri-grams, .. from.
      `minLength` - - minimal length
      `maxLength` - - maximal length

  - ### add

    public void add(CharSequence chars, int minLength, int maxLength)
    Adds character NGrams to the current instance.
    Parameters:
      `chars` -
      `minLength` -
      `maxLength` -

  - ### remove

    public void remove(StringList tokens)
    Removes the specified tokens form the NGram model, they are just dropped.
    Parameters:
      `tokens` -

  - ### contains

    public boolean contains(StringList tokens)
    Checks fit he given tokens are contained by the current instance.
    Parameters:
      `tokens` -
    Returns:
      true if the ngram is contained

  - ### size

    public int size()
    Retrieves the number of `StringList` entries in the current instance.
    Returns:
      number of different grams

  - ### iterator

    public Iterator<StringList> iterator()
    Retrieves an `Iterator` over all `StringList` entries.
    Specified by:
      `iterator` in interface `Iterable<StringList>`
    Returns:
      iterator over all grams

  - ### numberOfGrams

    public int numberOfGrams()
    Retrieves the total count of all Ngrams.
    Returns:
      total count of all ngrams

  - ### cutoff

    public void cutoff(int cutoffUnder, int cutoffOver)
    Deletes all ngram which do appear less than the cutoffUnder value and more often than the cutoffOver value.
    Parameters:
      `cutoffUnder` -
      `cutoffOver` -

  - ### toDictionary

    public Dictionary toDictionary()
    Creates a dictionary which contain all `StringList` which are in the current `NGramModel`.

    Entries which are only different in the case are merged into one.

    Calling this method is the same as calling `toDictionary(boolean)` with true.

    Returns:
      a dictionary of the ngrams

  - ### toDictionary

    public Dictionary toDictionary(boolean caseSensitive)
    Creates a dictionary which contains all `StringList`s which are in the current `NGramModel`.
    Parameters:
      `caseSensitive` - Specifies whether case distinctions should be kept in the creation of the dictionary.
    Returns:
      a dictionary of the ngrams

  - ### serialize

    public void serialize(OutputStream out) throws IOException
    Writes the ngram instance to the given `OutputStream`.
    Parameters:
      `out` -
    Throws:
      `IOException` - if an I/O Error during writing occurs

  - ### equals

    public boolean equals(Object obj)
    Overrides:
      `equals` in class `Object`

  - ### toString

    public String toString()
    Overrides:
      `toString` in class `Object`

  - ### hashCode

    public int hashCode()
    Overrides:
      `hashCode` in class `Object`