com.db4o.internal.query.processor

Class QConstraints

java.lang.Object

com.db4o.internal.query.processor.QCon

com.db4o.internal.query.processor.QConstraints

All Implemented Interfaces:

Visitor4, Constraint, Constraints, Unversioned

public class QConstraints
extends QCon
implements Constraints

Array of constraints for queries. Necessary to be returned to Query#constraints()

Field Summary

Fields inherited from class com.db4o.internal.query.processor.QCon

_children, i_evaluator, i_parent

Method Summary

Methods

Modifier and Type	Method and Description
Constraint	contains() sets the evaluation mode to string contains comparison.
Constraint	endsWith(boolean caseSensitive) sets the evaluation mode to string endsWith comparison.
Constraint	equal() Used in conjunction with Constraint.smaller() or Constraint.greater() to create constraints like "smaller or equal", "greater or equal".
java.lang.Object	getObject() returns the Object the query graph was constrained with to create this Constraint.
Constraint	greater() sets the evaluation mode to >.
Constraint	identity() sets the evaluation mode to identity comparison.
Constraint	like() sets the evaluation mode to "like" comparison.
Constraint	not() turns on not() comparison.
Constraint	smaller() sets the evaluation mode to <.
Constraint	startsWith(boolean caseSensitive) sets the evaluation mode to string startsWith comparison.
Constraint[]	toArray() returns an array of the contained Constraint objects.

Methods inherited from class com.db4o.internal.query.processor.QCon

and, byExample, canBeIndexLeaf, canLoadByIndex, childrenCount, container, evaluator, getField, hasChildren, hasJoins, hasObjectInParentPath, hasParent, id, identityID, internalSetProcessedByIndex, iterateChildren, iterateJoins, onSameFieldAs, or, parent, processedByIndex, setCandidates, setProcessedByIndex, streamLock, transaction, visit

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.db4o.query.Constraint

and, byExample, or

Method Detail

toArray

public Constraint[] toArray()

Description copied from interface: Constraints

returns an array of the contained Constraint objects.

Specified by:

toArray in interface Constraints

Returns:

an array of the contained Constraint objects.

contains

public Constraint contains()

Description copied from interface: Constraint

sets the evaluation mode to string contains comparison. The contains comparison is case sensitive. For example:
Pilot pilot = new Pilot("Test Pilot1", 100);
container.store(pilot);
...
query.constrain(Pilot.class);
// All pilots with the name containing "est" will be retrieved
query.descend("name").constrain("est").contains();

Specified by:

contains in interface Constraint

Overrides:

contains in class QCon

Returns:

this Constraint to allow the chaining of method calls.

See Also:

like() for case insensitive string comparison

equal

public Constraint equal()

Description copied from interface: Constraint

Used in conjunction with Constraint.smaller() or Constraint.greater() to create constraints like "smaller or equal", "greater or equal". For example:
query.constrain(Pilot.class);
query.descend("points").constrain(101).smaller().equal();
will return all pilots with points <= 101.

Specified by:

equal in interface Constraint

Overrides:

equal in class QCon

Returns:

this Constraint to allow the chaining of method calls.

greater

public Constraint greater()

Description copied from interface: Constraint

sets the evaluation mode to >. For example:
query.constrain(Pilot.class);
query.descend("points").constrain(101).greater()
will return all pilots with points > 101.

Specified by:

greater in interface Constraint

Overrides:

greater in class QCon

Returns:

this Constraint to allow the chaining of method calls.

identity

public Constraint identity()

Description copied from interface: Constraint

sets the evaluation mode to identity comparison. In this case only objects having the same database identity will be included in the result set. For example:
Pilot pilot = new Pilot("Test Pilot1", 100);
Car car = new Car("BMW", pilot);
container.store(car);
// Change the name, the pilot instance stays the same
pilot.setName("Test Pilot2");
// create a new car
car = new Car("Ferrari", pilot);
container.store(car);
Query query = container.query();
query.constrain(Car.class);
// All cars having pilot with the same database identity
// will be retrieved. As we only created Pilot object once
// it should mean all car objects
query.descend("_pilot").constrain(pilot).identity();

Specified by:

identity in interface Constraint

Overrides:

identity in class QCon

Returns:

this Constraint to allow the chaining of method calls.

not

public Constraint not()

Description copied from interface: Constraint

turns on not() comparison. All objects not fullfilling the constrain condition will be returned. For example:
Pilot pilot = new Pilot("Test Pilot1", 100);
container.store(pilot);
...
query.constrain(Pilot.class);
query.descend("name").constrain("t0").endsWith(true).not();

Specified by:

not in interface Constraint

Overrides:

not in class QCon

Returns:

this Constraint to allow the chaining of method calls.

like

public Constraint like()

Description copied from interface: Constraint

sets the evaluation mode to "like" comparison. This mode will include all objects having the constrain expression somewhere inside the string field. For example:
Pilot pilot = new Pilot("Test Pilot1", 100);
container.store(pilot);
...
query.constrain(Pilot.class);
// All pilots with the name containing "est" will be retrieved
query.descend("name").constrain("est").like();

Specified by:

like in interface Constraint

Overrides:

like in class QCon

Returns:

this Constraint to allow the chaining of method calls.

startsWith

public Constraint startsWith(boolean caseSensitive)

Description copied from interface: Constraint

sets the evaluation mode to string startsWith comparison. For example:
Pilot pilot = new Pilot("Test Pilot0", 100);
container.store(pilot);
...
query.constrain(Pilot.class);
query.descend("name").constrain("Test").startsWith(true);

Specified by:

startsWith in interface Constraint

Overrides:

startsWith in class QCon

Parameters:

caseSensitive - comparison will be case sensitive if true, case insensitive otherwise

Returns:

this Constraint to allow the chaining of method calls.

endsWith

public Constraint endsWith(boolean caseSensitive)

Description copied from interface: Constraint

sets the evaluation mode to string endsWith comparison. For example:
Pilot pilot = new Pilot("Test Pilot0", 100);
container.store(pilot);
...
query.constrain(Pilot.class);
query.descend("name").constrain("T0").endsWith(false);

Specified by:

endsWith in interface Constraint

Overrides:

endsWith in class QCon

Parameters:

caseSensitive - comparison will be case sensitive if true, case insensitive otherwise

Returns:

this Constraint to allow the chaining of method calls.

smaller

public Constraint smaller()

Description copied from interface: Constraint

sets the evaluation mode to <. For example:
query.constrain(Pilot.class);
query.descend("points").constrain(101).smaller()
will return all pilots with points < 101.

Specified by:

smaller in interface Constraint

Overrides:

smaller in class QCon

Returns:

this Constraint to allow the chaining of method calls.

getObject

public java.lang.Object getObject()

Description copied from interface: Constraint

returns the Object the query graph was constrained with to create this Constraint.

Specified by:

getObject in interface Constraint

Overrides:

getObject in class QCon

Returns:

Object the constraining object.