org.orekit.data

Class DataProvidersManager

java.lang.Object

org.orekit.data.DataProvidersManager

public class DataProvidersManager
extends Object

This class manages supported data providers.

This class is the primary 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 Summary

Fields

Modifier and Type	Field and Description
static String	OREKIT_DATA_PATH Name of the property defining the root directories or zip/jar files path for default configuration.

Constructor Summary

Constructors

Constructor and Description
DataProvidersManager() Build an instance with default configuration.

Method Summary

Modifier and Type	Method and Description
void	addDefaultProviders() Add the default providers configuration.
void	addFilter(DataFilter filter) Add a data filter.
void	addProvider(DataProvider provider) Add a data provider to the supported list.
NamedData	applyAllFilters(NamedData original) Apply all the relevant data filters, taking care of layers.
void	clearFilters() Remove all data filters, except the predefined ones.
void	clearLoadedDataNames() Clear the set of data file names that have been loaded.
void	clearProviders() Remove all data providers.
boolean	feed(String supportedNames, DataLoader loader) Feed a data file loader by browsing all data providers.
static DataProvidersManager	getInstance() Deprecated. This class is no longer a singleton. In order to support loading multiple data sets code should be updated to accept an instance of this class. If you need to maintain compatibility with Orekit 10.0's behavior use the default data context: DataContext.getDefault().getDataProvidersManager().
Set<String>	getLoadedDataNames() Get an unmodifiable view of the set of data file names that have been loaded.
List<DataProvider>	getProviders() Get an unmodifiable view of the list of supported providers.
boolean	isSupported(DataProvider provider) Check if some provider is supported.
DataProvider	removeProvider(DataProvider provider) Remove one provider.

Methods inherited from class java.lang.Object

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

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

Constructor Detail

DataProvidersManager

public DataProvidersManager()

Build an instance with default configuration.

Method Detail

getInstance

@Deprecated
 @DefaultDataContext
public static DataProvidersManager getInstance()

Deprecated. This class is no longer a singleton. In order to support loading multiple data sets code should be updated to accept an instance of this class. If you need to maintain compatibility with Orekit 10.0's behavior use the default data context: DataContext.getDefault().getDataProvidersManager().

Get the default instance.

Returns:

default instance of the manager.

See Also:

DataContext

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.

addProvider

public void addProvider(DataProvider provider)

Add a data provider to the supported list.

Parameters:

provider - data provider to add

See Also:

removeProvider(DataProvider), clearProviders(), isSupported(DataProvider), getProviders()

removeProvider

public DataProvider removeProvider(DataProvider provider)

Remove one provider.

Parameters:

provider - provider instance to remove

Returns:

instance removed (null if the provider was not already present)

Since:

5.1

See Also:

addProvider(DataProvider), clearProviders(), isSupported(DataProvider), getProviders()

clearProviders

public void clearProviders()

Remove all data providers.

See Also:

addProvider(DataProvider), removeProvider(DataProvider), isSupported(DataProvider), getProviders()

addFilter

public void addFilter(DataFilter filter)

Add a data filter.

Parameters:

filter - filter to add

Since:

9.2

See Also:

applyAllFilters(NamedData), clearFilters()

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()

isSupported

public boolean isSupported(DataProvider provider)

Check if some provider is supported.

Parameters:

provider - provider to check

Returns:

true if the specified provider instance is already in the supported list

Since:

5.1

See Also:

addProvider(DataProvider), removeProvider(DataProvider), clearProviders(), getProviders()

getProviders

public List<DataProvider> getProviders()

Get an unmodifiable view of the list of supported providers.

Returns:

unmodifiable view of the list of supported providers

See Also:

addProvider(DataProvider), removeProvider(DataProvider), clearProviders(), isSupported(DataProvider)

getLoadedDataNames

public Set<String> getLoadedDataNames()

Get an unmodifiable view of the set of data file names that have been loaded.

The names returned are exactly the ones that were given to the DataLoader.loadData method.

Returns:

unmodifiable view of the set of data file names that have been loaded

See Also:

feed(String, DataLoader), clearLoadedDataNames()

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