Class InstallationScriptProvider

Object
InstallationResources
InstallationScriptProvider
public abstract class InstallationScriptProvider extends InstallationResources
Provides the SQL scripts needed for creating a local copy of a geodetic dataset. This is used mostly for automatic installation of the EPSG dataset, but could also be used for other registries. Implementations of this class are discovered automatically by EPSGFactory if they are declared in the module-info​.class file as providers of the org​.apache​.sis​.setup​.Installation­Resources service.

How this class is used

The first time that an EPSGData­Access needs to be instantiated, EPSGFactory verifies if the EPSG database exists. If it does not, then:
  1. EPSGFactory​.install(Connection) searches for the first instance of Installation­Resources for which the set of authorities contains "EPSG".
  2. The license will be shown to the user if the application allows that (for example, when running as a console application).
  3. If the user accepts the EPSG terms of use, then this class iterates over all readers provided by open­Script(String, int) and executes the SQL statements (not necessarily verbatim, as the installation process may adapt some SQL statements to the target database).
Since:
0.7

  • Field Details

    • PREPARE

      @Deprecated(since="1.5", forRemoval=true) protected static final String PREPARE
      Deprecated, for removal: This API element is subject to removal in a future version.
      Ignored since the upgrade to version 10+ of EPSG because too dependent of the database schema.
      A sentinel value for the content of the script to execute before the SQL scripts provided by the authority. This is an Apache SIS build-in script for replacing the VARCHAR type of some columns by enumeration types, in order to constraint the values to the codes recognized by EPSGData­Access. Those enumerations are not mandatory for allowing EPSGFactory to work, but improve data integrity.
      See Also:

    • FINISH

      @Deprecated(since="1.5", forRemoval=true) protected static final String FINISH
      Deprecated, for removal: This API element is subject to removal in a future version.
      Ignored since the upgrade to version 10+ of EPSG because too dependent of the database schema.
      A sentinel value for the content of the script to execute after the SQL scripts provided by the authority. This is an Apache SIS build-in script for creating indexes or performing other manipulations that help SIS to use the dataset. Those indexes are not mandatory for allowing EPSGFactory to work, but improve performances.
      See Also:

  • Constructor Details

    • InstallationScriptProvider

      protected InstallationScriptProvider(String authority, String... resources)
      Creates a new provider which will read script files of the given names in the given order. The given names are often filenames, but not necessarily (it is okay to use those names only as labels).
      Example of argument values
      Authority Resources
      EPSG {"Tables.sql", "Data.sql", "FKeys.sql", "Indexes.sql"}
      Parameters:
      authority - the authority (typically "EPSG"), or null if not available.
      resources - names of the SQL scripts to read (typically filenames).
      See Also:

  • Method Details

    • getAuthorities

      public Set<String> getAuthorities()
      Returns the identifiers of the dataset installed by the SQL scripts. The values currently recognized by SIS are:
      • "EPSG" for the EPSG geodetic dataset.
      The default implementation returns the authority given at construction time, or an empty set if that authority was null. An empty set means that the provider does not have all needed resources or does not have permission to distribute the installation scripts.
      Specified by:
      get­Authorities in class Installation­Resources
      Returns:
      identifiers of SQL scripts that this instance can distribute.

    • getResourceNames

      public String[] getResourceNames(String authority) throws IOException
      Returns the names of all SQL scripts to execute. This is a copy of the array of names given to the constructor. Those names are often filenames, but not necessarily (they may be just labels).
      Specified by:
      get­Resource­Names in class Installation­Resources
      Parameters:
      authority - the value given at construction time (e.g. "EPSG").
      Returns:
      the names of all SQL scripts to execute.
      Throws:
      Illegal­Argument­Exception - if the given authority argument is not the expected value.
      IOException - if fetching the script names required an I/O operation and that operation failed.

    • openScript

      public BufferedReader openScript(String authority, int resource) throws IOException
      Returns a reader for the SQL script at the given index. The script may be read, for example, from a local file or from a resource in a JAR file. The returned Buffered­Reader instance shall be closed by the caller.

      Default implementation

      The default implementation delegates to open­Stream(String). The input stream returned by open­Stream(…) is assumed encoded in UTF-8 and is wrapped in a Line­Number­Reader.
      Specified by:
      open­Script in class Installation­Resources
      Parameters:
      authority - the value given at construction time (e.g. "EPSG").
      resource - index of the SQL script to read, from 0 inclusive to get­Resource­Names(authority)​.length exclusive.
      Returns:
      a reader for the content of SQL script to execute.
      Throws:
      Illegal­Argument­Exception - if the given authority argument is not the expected value.
      Index­Out­Of­Bounds­Exception - if the given resource argument is out of bounds.
      File­Not­Found­Exception - if the SQL script of the given name has not been found.
      IOException - if an error occurred while creating the reader.

    • openStream

      protected abstract InputStream openStream(String name) throws IOException
      Opens the input stream for the SQL script of the given name. This method is invoked by the default implementation of open­Script(String, int). The returned input stream does not need to be buffered.

      Example 1

      If this Installation­Script­Provider instance gets the SQL scripts from files in a well-known directory and if the names given at construction time are filenames in that directory, then this method can be implemented as below: 
           protected InputStream openStream(String name) throws IOException {
         return Files.newInputStream(directory.resolve(name));
     }

      Example 2

      If this Installation­Script­Provider instance gets the SQL scripts from resources bundled in the same JAR file and in the same package as the subclass, this method can be implemented as below: 
           protected InputStream openStream(String name) {
         return MyClass.getResourceAsStream(name);
     }
      Parameters:
      name - name of the script file to open. Can be null if the resource is not found.
      Returns:
      an input stream opened of the given script file.
      Throws:
      IOException - if an error occurred while opening the file.