Package org.orekit.data

Class DataProvidersManager

  • public class DataProvidersManager
extends Object
    Singleton class managing all supported data providers.

    This class is the single point of access for all data loading features. It is used for example to load Earth Orientation Parameters used by IERS frames, to load UTC leap seconds used by time scales, to load planetary ephemerides ...

    It is user-customizable: users can add their own data providers at will. This allows them for example to use a database or an existing data loading library in order to embed an Orekit enabled application in a global system with its own data handling mechanisms. There is no upper limitation on the number of providers, but often each application will use only a few.

    If the list of providers is empty when attempting to feed a file loader, the addDefaultProviders() method is called automatically to set up a default configuration. This default configuration contains one data provider for each component of the path-like list specified by the java property orekit.data.path. See the feed method documentation for further details. The default providers configuration is not set up if the list is not empty. If users want to have both the default providers and additional providers, they must call explicitly the addDefaultProviders() method.

    The default configuration uses a predefined set of data filters that already handled gzip-compressed files (recognized by the .gz suffix) and Unix-compressed files (recognized by the .Z suffix). Users can add custom filters for handling specific types of filters (decompression, deciphering...).

    Author:
    Luc Maisonobe
    See Also:
    DirectoryCrawler, ClasspathCrawler

    • Field Detail

      • OREKIT_DATA_PATH

        public static final String OREKIT_DATA_PATH
        Name of the property defining the root directories or zip/jar files path for default configuration.
        See Also:
        Constant Field Values

    • Method Detail

      • getInstance

        public static DataProvidersManager getInstance()
        Get the unique instance.
        Returns:
        unique instance of the manager.

      • addDefaultProviders

        public void addDefaultProviders()
        Add the default providers configuration.

        The default configuration contains one data provider for each component of the path-like list specified by the java property orekit.data.path.

        If the property is not set or is null, no data will be available to the library (for example no pole corrections will be applied and only predefined UTC steps will be taken into account). No errors will be triggered in this case.

        If the property is set, it must contains a list of existing directories or zip/jar archives. One DirectoryCrawler instance will be set up for each directory and one ZipJarCrawler instance (configured to look for the archive in the filesystem) will be set up for each zip/jar archive. The list elements in the java property are separated using the standard path separator for the operating system as returned by System.getProperty("path.separator"). This standard path separator is ":" on Linux and Unix type systems and ";" on Windows types systems.

      • clearFilters

        public void clearFilters()
        Remove all data filters, except the predefined ones.
        Since:
        9.2
        See Also:
        addFilter(DataFilter)

      • applyAllFilters

        public NamedData applyAllFilters​(NamedData original)
                          throws IOException
        Apply all the relevant data filters, taking care of layers.

        If several filters can be applied, they will all be applied as a stack, even recursively if required. This means that if filter A applies to files with names of the form base.ext.a and filter B applies to files with names of the form base.ext.b, then providing base.ext.a.b.a will result in filter A being applied on top of filter B which itself is applied on top of another instance of filter A.

        Parameters:
        original - original named data
        Returns:
        fully filtered named data
        Throws:
        IOException - if some data stream cannot be filtered
        Since:
        9.2
        See Also:
        addFilter(DataFilter), clearFilters()

      • clearLoadedDataNames

        public void clearLoadedDataNames()
        Clear the set of data file names that have been loaded.
        See Also:
        getLoadedDataNames()

      • feed

        public boolean feed​(String supportedNames,
                    DataLoader loader)
        Feed a data file loader by browsing all data providers.

        If this method is called with an empty list of providers, a default providers configuration is set up. This default configuration contains only one data provider: a DirectoryCrawler instance that loads data from files located somewhere in a directory hierarchy. This default provider is not added if the list is not empty. If users want to have both the default provider and other providers, they must add it explicitly.

        The providers are used in the order in which they were added. As soon as one provider is able to feed the data loader, the loop is stopped. If no provider is able to feed the data loader, then the last error triggered is thrown.

        Parameters:
        supportedNames - regular expression for file names supported by the visitor
        loader - data loader to use
        Returns:
        true if some data has been loaded