Package org.jetbrains.mps.openapi.persistence

Class NullDataSource

java.lang.Object

org.jetbrains.mps.openapi.persistence.NullDataSource

All Implemented Interfaces:

DataSource

public final class NullDataSource
extends Object
implements DataSource

An empty implementation of the DataSource interface.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	NullDataSource.NullDataSourceType

Constructor Summary

Constructors

Constructor	Description
NullDataSource()

Method Summary

Modifier and Type	Method	Description
void	addListener(DataSourceListener listener)	Registers listeners which need to be notified about changes in the underlying data source.
String	getLocation()	Yields a string representation for the location of the data source (if applicable)
long	getTimestamp()	Retrieves the last modification timestamp.
DataSourceType	getType()	Defines a data source type for this kind of data sources.
boolean	isReadOnly()	Sometimes there is a possibility to edit DataSource, though it is not available on this level.
void	removeListener(DataSourceListener listener)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jetbrains.mps.openapi.persistence.DataSource

isAlive, refresh

Constructor Detail

NullDataSource

public NullDataSource()

Method Detail

getLocation

@NotNull
public String getLocation()

Description copied from interface: DataSource

Yields a string representation for the location of the data source (if applicable)

Specified by:

getLocation in interface DataSource

addListener

public void addListener(@NotNull
                        DataSourceListener listener)

Description copied from interface: DataSource

Registers listeners which need to be notified about changes in the underlying data source. It is the responsibility of the DataSource to detect such updates and notify the listeners. if

Specified by:

addListener in interface DataSource

removeListener

public void removeListener(@NotNull
                           DataSourceListener listener)

Specified by:

removeListener in interface DataSource

getTimestamp

public long getTimestamp()

Description copied from interface: DataSource

Retrieves the last modification timestamp. The timestamp should reliably reflect all external changes to the data source. fixme what a great idea to encode things in the timestamp, why not read-only property is denoted by -2?

Specified by:

getTimestamp in interface DataSource

Returns:

0 if timestamp is not supported for the source, or -1 if the source is dead (like when file is deleted)

isReadOnly

public boolean isReadOnly()

Description copied from interface: DataSource

Sometimes there is a possibility to edit DataSource, though it is not available on this level. For examples please see StreamDataSource, MultiStreamDataSource.

Specified by:

isReadOnly in interface DataSource

Returns:

whether this data source can be changed. fixme not clear: change from api like #openOutputStream or changed externally?

getType

@NotNull
public DataSourceType getType()

Description copied from interface: DataSource

Defines a data source type for this kind of data sources. The data source type notion is strongly associated with the possibility to provide DataSourceFactory and ModelFactory custom mappings. See DataSourceFactoryRuleService and ModelFactoryService for the implementation details.

Specified by:

getType in interface DataSource

Returns:

the unique data source type for this instance of data source if the developer wants others to be able to change the default behavior of this data source (register with the same key) or if he desires to associate this data source with some specific model factory.