Package org.apache.uima.cas

Class ConstraintFactory

java.lang.Object
org.apache.uima.cas.ConstraintFactory
Direct Known Subclasses:
ConstraintFactoryImpl
public abstract class ConstraintFactory extends Object
Methods to create FSMatchConstraints for filtered iterators or other use. A constraint is an object which represents a test or a series of tests joined with "and" or "or". Each test consists of a test predicate plus an optional "path" which specifies how to walk through a chain of references, starting from a feature structure being tested, to reach the value to be tested.

Tests include

  • type subsumption --(satisfied if the CAS feature structure being tested is of a specified type (or is a subtype of that type).
  • value equality
  • for numeric values - range testing
Constraints can be used by calling their "match" method, passing as an argument the value to test. If the constraint includes the "path", the argument is a feature structure; the path specifies how to reach the value to test, starting with the feature structure. Otherwise, the value to test depends on the constraint; for an FSIntConstraint, for instance, the value would be an integer.

  • Constructor Details

    • ConstraintFactory

      public ConstraintFactory()

  • Method Details

    • createTypeConstraint

      public abstract FSTypeConstraint createTypeConstraint()
      Create a new type constraint. A type constraint contains one or more types to test against. A type constraint must be initialized by adding one or more types to it. The match is true if any of the types are the same or a super type of the feature structure being tested by the constraint.
      Returns:
      A new type constraint with the type set to the top type.

    • createIntConstraint

      public abstract FSIntConstraint createIntConstraint()
      Create a new int constraint. An int constraint must be initialized after it's created by adding one or more tests to it.
      Returns:
      A new int constraint, completely unconstrained.

    • createFloatConstraint

      public abstract FSFloatConstraint createFloatConstraint()
      Create a new float constraint. A float constraint must be initialized after it's created by adding one or more tests to it.
      Returns:
      A new float constraint, completely unconstrained.

    • createStringConstraint

      public abstract FSStringConstraint createStringConstraint()
      Create a new String constraint. A String constraint must be initialized after it's created by adding one or more tests to it.
      Returns:
      A new String constraint, completely unconstrained.

    • createBooleanConstraint

      public abstract FSBooleanConstraint createBooleanConstraint()
      Create a new boolean constraint. A boolean constraint must be initialized after it's created by adding one or more tests to it.
      Returns:
      A new boolean constraint, completely unconstrained.

    • embedConstraint

      public abstract FSMatchConstraint embedConstraint(FeaturePath path, FSConstraint constraint)
      Combine a constraint test with a path from a feature structure instance to the value to be tested. This is called "embedding" a constraint under a path. For example, create an int constraint, and then embed it under some int valued feature, such as the start feature of an annotation.
      Parameters:
      path - The path to embed the constraint under. Create a new path with CAS.createFeaturePath().
      constraint - The constraint to be embedded.
      Returns:
      A new FSMatchConstraint.

    • embedConstraint

      public abstract FSMatchConstraint embedConstraint(ArrayList<String> path, FSConstraint constraint)
      Embed a constraint under a path. For example, create an int constraint, and then embed it under some int valued feature, such as the start feature of an annotation.
      Parameters:
      path - The path to embed the constraint under. This is a list of Feature names.
      constraint - The constraint to be embedded.
      Returns:
      A new FSMatchConstraint.

    • and

      public abstract FSMatchConstraint and(FSMatchConstraint c1, FSMatchConstraint c2)
      Conjoin two constraints.
      Parameters:
      c1 - The first conjunct.
      c2 - The second conjunct.
      Returns:
      A new FSMatchConstraint, representing the conjunction of c1 and c2.

    • or

      public abstract FSMatchConstraint or(FSMatchConstraint c1, FSMatchConstraint c2)
      Disjoin two constraints.
      Parameters:
      c1 - The first disjunct.
      c2 - The second disjunct.
      Returns:
      A new FSMatchConstraint, representing the disjunction of c1 and c2.

    • instance

      public static ConstraintFactory instance()
      Create a new constraint factory.
      Returns:
      A new ConstraintFactory instance.