### Contraction Expander.

A contraction expander takes a contracted form as input and produces an expanded (uncontracted) form as output. For example, the English language contraction expander expands "don't" to "do not" and "niltow" to "wilt thou not."

All MorphAdorner contraction expanders must implement the {@link edu.northwestern.at.morphadorner.corpuslinguistics.contractionexpander.ContractionExpander} interface. The {@link edu.northwestern.at.morphadorner.corpuslinguistics.contractionexpander.ContractionExpanderFactory} provides the mechanism for instantiating a default or specified instance of a ContractionExpander implementation. The {@link edu.northwestern.at.morphadorner.corpuslinguistics.contractionexpander.AbstractContractionExpander} serves as a base class for deriving concrete implementations of contraction expanders. The {@link edu.northwestern.at.morphadorner.corpuslinguistics.contractionexpander.DefaultContractionExpander} if for English language contractions and just wraps {@link edu.northwestern.at.morphadorner.corpuslinguistics.contractionexpander.EnglishContractionExpander}.