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 `FSMatchConstraint`s 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 Summary

    Constructors
    Constructor and Description
    `ConstraintFactory()`

  - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `abstract FSMatchConstraint` | `and(FSMatchConstraint c1, FSMatchConstraint c2)` Conjoin two constraints.
    `abstract FSBooleanConstraint` | `createBooleanConstraint()` Create a new boolean constraint.
    `abstract FSFloatConstraint` | `createFloatConstraint()` Create a new float constraint.
    `abstract FSIntConstraint` | `createIntConstraint()` Create a new int constraint.
    `abstract FSStringConstraint` | `createStringConstraint()` Create a new String constraint.
    `abstract FSTypeConstraint` | `createTypeConstraint()` Create a new type constraint.
    `abstract FSMatchConstraint` | `embedConstraint(ArrayList<String> path, FSConstraint constraint)` Embed a constraint under a path.
    `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.
    `static ConstraintFactory` | `instance()` Create a new constraint factory.
    `abstract FSMatchConstraint` | `or(FSMatchConstraint c1, FSMatchConstraint c2)` Disjoin two constraints.

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

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### ConstraintFactory

          public ConstraintFactory()

  - ### Method Detail

    - #### 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.

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