Package org.jetbrains.mps.openapi.persistence

Interface DataSource

  • All Known Subinterfaces:
    MultiStreamDataSource, StreamDataSource
    All Known Implementing Classes:
    NullDataSource
    public interface DataSource
    Represents a location abstraction + some means to work with data at the location. Usually DataSource points to the model data sources. For example it can be based on files, internet content, database content, etc. NB: Must not contain any information on the storage format specifics -- all that belongs to the ModelFactory. For implementation consider extending jetbrains.mps.extapi.persistence.DataSourceBase, MultiStreamSourceBase, StreamSourceBase fixme rather we need to separate the location part of the accessing the data at the location right now we have both here, but no abstract means to read/write because on this level there is no common access mechanism that we could offer

    • Method Detail

      • getLocation

        @NotNull
String getLocation()
        Yields a string representation for the location of the data source (if applicable)

      • isAlive

        default boolean isAlive()
        Returns:
        if the source is alive, like the file exists or the connection is not closed

      • getTimestamp

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

      • getType

        @Nullable
default DataSourceType getType()
        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.
        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.

      • isReadOnly

        boolean isReadOnly()
        Sometimes there is a possibility to edit DataSource, though it is not available on this level. For examples please see StreamDataSource, MultiStreamDataSource.
        Returns:
        whether this data source can be changed. fixme not clear: change from api like #openOutputStream or changed externally?

      • addListener

        default void addListener​(@NotNull
                         DataSourceListener listener)
        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

      • refresh

        default void refresh()