Package opennlp.tools.chunker

Class DefaultChunkerContextGenerator

  • All Implemented Interfaces:
    ChunkerContextGenerator, BeamSearchContextGenerator<TokenTag>
    public class DefaultChunkerContextGenerator
extends java.lang.Object
implements ChunkerContextGenerator
    Features based on chunking model described in Fei Sha and Fernando Pereira. Shallow parsing with conditional random fields. In Proceedings of HLT-NAACL 2003. Association for Computational Linguistics, 2003.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.String[] getContext​(int i, java.lang.String[] toks, java.lang.String[] tags, java.lang.String[] preds)
      Returns the contexts for chunking of the specified index.
      java.lang.String[] getContext​(int index, java.lang.String[] tokens, java.lang.String[] postags, java.lang.String[] priorDecisions, java.lang.Object[] additionalContext)  
      java.lang.String[] getContext​(int index, TokenTag[] sequence, java.lang.String[] priorDecisions, java.lang.Object[] additionalContext)
      Returns the context for the specified position in the specified sequence (list).

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • DefaultChunkerContextGenerator

        public DefaultChunkerContextGenerator()
        Creates the default context generator a chunker.

    • Method Detail

      • getContext

        public java.lang.String[] getContext​(int index,
                                     java.lang.String[] tokens,
                                     java.lang.String[] postags,
                                     java.lang.String[] priorDecisions,
                                     java.lang.Object[] additionalContext)

      • getContext

        public java.lang.String[] getContext​(int i,
                                     java.lang.String[] toks,
                                     java.lang.String[] tags,
                                     java.lang.String[] preds)
        Description copied from interface: ChunkerContextGenerator
        Returns the contexts for chunking of the specified index.
        Specified by:
        getContext in interface ChunkerContextGenerator
        Parameters:
        i - The index of the token in the specified toks array for which the context should be constructed.
        toks - The tokens of the sentence. The toString methods of these objects should return the token text.
        tags - The POS tags for the the specified tokens.
        preds - The previous decisions made in the taging of this sequence. Only indices less than i will be examined.
        Returns:
        An array of predictive contexts on which a model basis its decisions.

      • getContext

        public java.lang.String[] getContext​(int index,
                                     TokenTag[] sequence,
                                     java.lang.String[] priorDecisions,
                                     java.lang.Object[] additionalContext)
        Description copied from interface: BeamSearchContextGenerator
        Returns the context for the specified position in the specified sequence (list).
        Specified by:
        getContext in interface BeamSearchContextGenerator<TokenTag>
        Parameters:
        index - The index of the sequence.
        sequence - The sequence of items over which the beam search is performed.
        priorDecisions - The sequence of decisions made prior to the context for which this decision is being made.
        additionalContext - Any addition context specific to a class implementing this interface.
        Returns:
        the context for the specified position in the specified sequence.