org.apache.uima.cas
Class ConstraintFactory

java.lang.Object
  org.apache.uima.cas.ConstraintFactory

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 Summary

ConstraintFactory()

Method Summary

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.