Package org.apache.sis.metadata

Class StateChanger

java.lang.Object

org.apache.sis.metadata.MetadataVisitor<Boolean>

org.apache.sis.metadata.StateChanger

final class StateChanger
extends MetadataVisitor<Boolean>

Invokes ModifiableMetadata.transitionTo(ModifiableMetadata.State) recursively on metadata elements.

Since:

0.3

Version:

1.0

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.sis.metadata.MetadataVisitor

MetadataVisitor.Filter

Field Summary

Fields

Modifier and Type	Field	Description
private Cloner	cloner	The cloner, created when first needed.
private ModifiableMetadata.State	target	The state to apply on all metadata objects.
private static final ThreadLocal<StateChanger>	VISITORS	The StateChanger instance in current use.

Fields inherited from class org.apache.sis.metadata.MetadataVisitor

SKIP_SIBLINGS

Constructor Summary

Constructors

Modifier	Constructor	Description
private	StateChanger()	Creates a new StateChanger instance.

Method Summary

Modifier and Type	Method	Description
private Object	applyTo(Object object)	Returns the given object, or a copy of the given object, with its state changed.
(package private) static void	applyTo(ModifiableMetadata.State target, ModifiableMetadata metadata)	Applies a state change on the given metadata object.
private void	applyToAll(Object[] array)	Recursively changes the state of all elements in the given array.
(package private) final ThreadLocal<StateChanger>	creator()	Returns the thread-local variable that created this StateChanger instance.
(package private) MetadataVisitor.Filter	preVisit(PropertyAccessor accessor)	Notifies MetadataVisitor that we want to visit all writable properties.
(package private) final Object	visit(Class<?> type, Object object)	Invoked for metadata instances on which to apply a change of state.

Methods inherited from class org.apache.sis.metadata.MetadataVisitor

getCurrentPropertyPath, result, setCurrentProperty, walk

Methods inherited from class java.lang.Object

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

Field Details

VISITORS

private static final ThreadLocal<StateChanger> VISITORS

The StateChanger instance in current use. The clean way would have been to pass the instance in argument to ModifiableMetadata.transitionTo(ModifiableMetadata.State). But above-cited method ix public and we do not want to expose StateChanger in public API. This thread-local is a workaround for that situation.

target

private ModifiableMetadata.State target

The state to apply on all metadata objects.

cloner

private Cloner cloner

The cloner, created when first needed.

Constructor Details

StateChanger

private StateChanger()

Creates a new StateChanger instance.

Method Details

applyTo

static void applyTo(ModifiableMetadata.State target,
 ModifiableMetadata metadata)

Applies a state change on the given metadata object. This is the implementation ModifiableMetadata.transitionTo(ModifiableMetadata.State) public method.

This is conceptually an instance (non-static) method. But the this value is not known by the caller, because doing otherwise would force us to give public visibility to classes that we want to keep package-private. The VISITORS thread local variable is used as a workaround for providing this instance without making StateChanger public.

creator

final ThreadLocal<StateChanger> creator()

Returns the thread-local variable that created this StateChanger instance. ThreadLocal.remove() will be invoked after MetadataVisitor finished to walk through the given metadata and all its children.

Overrides:

creator in class MetadataVisitor<Boolean>

preVisit

MetadataVisitor.Filter preVisit(PropertyAccessor accessor)

Notifies MetadataVisitor that we want to visit all writable properties.

Overrides:

preVisit in class MetadataVisitor<Boolean>

Parameters:

accessor - ignored.

Returns:

MetadataVisitor.Filter.WRITABLE, for iterating over all writable properties.

visit

final Object visit(Class<?> type,
 Object object)
            throws CloneNotSupportedException

Invoked for metadata instances on which to apply a change of state.

Specified by:

visit in class MetadataVisitor<Boolean>

Parameters:

type - ignored (can be null).

object - the object to transition to a different state.

Returns:

the given object or a copy of the given object with its state changed.

Throws:

CloneNotSupportedException

applyToAll

private void applyToAll(Object[] array)
                 throws CloneNotSupportedException

Recursively changes the state of all elements in the given array.

Throws:

CloneNotSupportedException

applyTo

private Object applyTo(Object object)
                throws CloneNotSupportedException

Returns the given object, or a copy of the given object, with its state changed. This method performs the following heuristic tests:

• If the specified object is an instance of ModifiableMetadata, then ModifiableMetadata.transitionTo(ModifiableMetadata.State) is invoked on that object.
• Otherwise, if the object is a collection, then the content is copied into a new collection of similar type, with values replaced by their unmodifiable variant.
• Otherwise, if the object implements the Cloneable interface, then a clone is returned.
• Otherwise, the object is assumed immutable and returned unchanged.

Parameters:

object - the object to transition to a different state.

Returns:

the given object or a copy of the given object with its state changed.

Throws:

CloneNotSupportedException