Package ca.cgjennings.apps.arkham.project

Class MetadataSource.ThreadedMetadataSource

java.lang.Object

ca.cgjennings.apps.arkham.project.MetadataSource

ca.cgjennings.apps.arkham.project.MetadataSource.ThreadedMetadataSource

Enclosing class:

MetadataSource

public abstract static class MetadataSource.ThreadedMetadataSource
extends MetadataSource

An abstract helper class for creating metadata sources that fill in some of their data from a background thread. This prevents blocking the user interface to complete potentially complex or time-consuming operations, such as generating a preview thumbnail. Be careful to observe Swing threading restrictions.

Nested Class Summary

Nested classes/interfaces inherited from class ca.cgjennings.apps.arkham.project.MetadataSource

MetadataSource.PropertyConsumer, MetadataSource.ThreadedMetadataSource

Field Summary

Fields inherited from class ca.cgjennings.apps.arkham.project.MetadataSource

ICON_AUTOMATION_SCRIPT, ICON_BLANK, ICON_CARD_LAYOUT, ICON_CLASS, ICON_CLASS_MAP, ICON_COLLECTION, ICON_CONVERSION_MAP, ICON_COPIES_LIST, ICON_DICT_CPL, ICON_DICT_TST, ICON_DOCUMENT, ICON_EON_DEFAULT, ICON_EON_EXTENSION, ICON_EON_LIBRARY, ICON_EON_PLUGIN, ICON_EON_THEME, ICON_FILE, ICON_FOLDER, ICON_FONT, ICON_HTML, ICON_IMAGE, ICON_JAVA, ICON_MARKDOWN, ICON_PACKED_BUNDLE, ICON_PLUGIN_ROOT, ICON_PROJECT, ICON_PROPERTIES, ICON_SCRIPT, ICON_SETTINGS, ICON_SILHOUETTES, ICON_STYLE_SHEET, ICON_TABLE, ICON_TASK, ICON_TASK_CASEBOOK, ICON_TASK_DECK, ICON_TASK_DOCUMENTATION, ICON_TASK_EXPBOARD, ICON_TASK_FACTORY, ICON_TASK_GROUP, ICON_TASK_PLUGIN, ICON_TEXT_INDEX, ICON_TILE_SET, ICON_TYPESCRIPT, ICON_VECTOR_IMAGE

Constructor Summary

Constructors

Constructor	Description
ThreadedMetadataSource()
ThreadedMetadataSource(boolean autopause)	If autopause is true, then pause() will be called before calling fillInThreadedMetadataImpl.

Method Summary

Modifier and Type	Method	Description
void	fillInMetadata(Member m, MetadataSource.PropertyConsumer pc)	Publishes metadata to a MetadataSource.PropertyConsumer.
protected void	fillInMetadataImpl(Member m, MetadataSource.PropertyConsumer pc)	Called to publish metadata to a consumer.
protected abstract void	fillInThreadedMetadataImpl(Member m, MetadataSource.PropertyConsumer pc)	This method is called from a background thread to allow the source to fill in additional metadata that may be expensive to generate.
protected boolean	pause(MetadataSource.PropertyConsumer pc)	Briefly pauses the current thread, then returns false if the property consumer is no longer valid or the thread was interrupted.

Methods inherited from class ca.cgjennings.apps.arkham.project.MetadataSource

add, add, add, add, appliesTo, getDefaultCharset, getDescription, getIcon, getMetadata, getSpecificInstanceFor, thumbnail

Methods inherited from class java.lang.Object

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

Constructor Detail

ThreadedMetadataSource

public ThreadedMetadataSource()

ThreadedMetadataSource

public ThreadedMetadataSource(boolean autopause)

If autopause is true, then pause() will be called before calling fillInThreadedMetadataImpl. If the property consumer becomes invalid during the pause, then the threaded metadata will not be requested.

Parameters:

autopause -

Method Detail

fillInMetadata

public void fillInMetadata(Member m,
                           MetadataSource.PropertyConsumer pc)

Description copied from class: MetadataSource

Publishes metadata to a MetadataSource.PropertyConsumer. This method may return before all available data has been published and continue to add new data as it becomes available. Once all of the available data has been published, if the consumer is still valid, its MetadataSource.PropertyConsumer.doneAddingProperties() method will be called.

The base class implementation calls MetadataSource.fillInMetadataImpl(ca.cgjennings.apps.arkham.project.Member, ca.cgjennings.apps.arkham.project.MetadataSource.PropertyConsumer) and then calls the consumer's MetadataSource.PropertyConsumer.doneAddingProperties() method. This will fill in the member's file type description and basic file-based metadata.

Note: If you want to create a metadata source that adds some properties from another thread (because they take time to provide), use MetadataSource.ThreadedMetadataSource as your base class.

Overrides:

fillInMetadata in class MetadataSource

pc - the entity that should receive property data

fillInMetadataImpl

protected void fillInMetadataImpl(Member m,
                                  MetadataSource.PropertyConsumer pc)

Description copied from class: MetadataSource

Called to publish metadata to a consumer. The base class will publish basic metadata including the file type description. Classes that override the default implementation should call the super implementation first to fill in this basic information.

Overrides:

fillInMetadataImpl in class MetadataSource

Parameters:

m - the member to publish metadata about

pc - the consumer to publish metadata to

pause

protected boolean pause(MetadataSource.PropertyConsumer pc)

Briefly pauses the current thread, then returns false if the property consumer is no longer valid or the thread was interrupted. This is called at the start of the background thread if the autopause option is enabled. It prevents the generation of expensive metadata when the user is quickly moving through the project members, such as when navigating the tree with the keyboard.

Returns:

true if the thread should proceed with generating metadata

fillInThreadedMetadataImpl

protected abstract void fillInThreadedMetadataImpl(Member m,
                                                   MetadataSource.PropertyConsumer pc)

This method is called from a background thread to allow the source to fill in additional metadata that may be expensive to generate.

Parameters:

m - the member to fill in data for

pc - the consumer that will accept the data being produced