Module org.tentackle.common
Package org.tentackle.common

Class DefaultServiceFinder

java.lang.Object
org.tentackle.common.DefaultServiceFinder
All Implemented Interfaces:
ServiceFinder
public class DefaultServiceFinder extends Object implements ServiceFinder
Default implementation of a ServiceFinder.
Author:
harald

  • Constructor Details

    • DefaultServiceFinder

      public DefaultServiceFinder(ClassLoader loader, String servicePath)
      Creates a service finder.
      Parameters:
      loader - optional classloader, null if use ClassLoader.getSystemClassLoader()
      servicePath - optional service path prefix, null if "META_INF/services/"

    • DefaultServiceFinder

      public DefaultServiceFinder(String servicePath)
      Creates a default service finder.
      The classloader used is Thread.currentThread().getContextClassLoader().
      Parameters:
      servicePath - optional service path prefix, null if "META_INF/services/"

    • DefaultServiceFinder

      public DefaultServiceFinder()
      Creates a default service finder.
      The classloader used is Thread.currentThread().getContextClassLoader().
      The servicepath is "META_INF/services/".

  • Method Details

    • getClassLoader

      public ClassLoader getClassLoader()
      Gets the classloader used by this finder.
      Specified by:
      getClassLoader in interface ServiceFinder
      Returns:
      the classloader, never null

    • getServicePath

      public String getServicePath()
      Gets the service path the finder is responsible for.
      Specified by:
      getServicePath in interface ServiceFinder
      Returns:
      the service path

    • findServiceURLs

      public Collection<URL> findServiceURLs(String serviceName)
      Finds URLs of a service by name.
      Specified by:
      findServiceURLs in interface ServiceFinder
      Parameters:
      serviceName - the service name, usually a classname
      Returns:
      the service's resource urls

    • findServiceConfigurations

      public Map<String,URL> findServiceConfigurations(String serviceName)
      Finds service configurations by service name.
      Iterations over the returned map are ordered by discovery along the classpath.
      Specified by:
      findServiceConfigurations in interface ServiceFinder
      Parameters:
      serviceName - the service name, usually a classname
      Returns:
      a map of the configured services and their corresponding URLs

    • findFirstServiceConfiguration

      public Map.Entry<String,URL> findFirstServiceConfiguration(String serviceName)
      Finds the first service configurations by service name.
      If similar configurations appear more than once on the classpath, the first is returned. Useful to override service default implementations.
      Specified by:
      findFirstServiceConfiguration in interface ServiceFinder
      Parameters:
      serviceName - the service name, usually a classname
      Returns:
      the service configuration entry

    • findUniqueServiceConfiguration

      public Map.Entry<String,URL> findUniqueServiceConfiguration(String serviceName)
      Finds a unique service configurations by service name.
      It is checked that the service is defined exactly once. Useful for factories, singletons and alike.
      Specified by:
      findUniqueServiceConfiguration in interface ServiceFinder
      Parameters:
      serviceName - the service name, usually a classname
      Returns:
      the service configuration entry

    • findServiceProviders

      public <T> Collection<Class<T>> findServiceProviders(Class<T> service) throws ClassNotFoundException
      Finds the service providers by service names.
      Specified by:
      findServiceProviders in interface ServiceFinder
      Type Parameters:
      T - the service type
      Parameters:
      service - the service class
      Returns:
      the classes providing this service
      Throws:
      ClassNotFoundException - if some provider could not be loaded

    • findFirstServiceProvider

      public <T> Class<T> findFirstServiceProvider(Class<T> service) throws ClassNotFoundException
      Finds the first service provider by service name.
      If similar configurations appear more than once on the classpath, the first is returned. Useful to override service default implementations.
      Specified by:
      findFirstServiceProvider in interface ServiceFinder
      Type Parameters:
      T - the service type
      Parameters:
      service - the service class
      Returns:
      the provider class
      Throws:
      ClassNotFoundException - if some provider could not be loaded

    • findUniqueServiceProvider

      public <T> Class<T> findUniqueServiceProvider(Class<T> service) throws ClassNotFoundException
      Finds the unique service provider by service class.
      Specified by:
      findUniqueServiceProvider in interface ServiceFinder
      Type Parameters:
      T - the service type
      Parameters:
      service - the service class
      Returns:
      the provider class
      Throws:
      ClassNotFoundException - if some provider could not be loaded

    • createNameMap

      public Map<String,String> createNameMap(String serviceName)
      Creates a map of classnames to mapped services.

      They key of the map is the service name. The value is the name providing the service which comes first in the classpath.

      Specified by:
      createNameMap in interface ServiceFinder
      Parameters:
      serviceName - the service class
      Returns:
      the map

    • createNameMapToAll

      public Map<String,Set<String>> createNameMapToAll(String serviceName)
      Creates a map of names to all mapped services.

      They key of the map is the service name. The value is a list of names providing the service ordered by discovery along the classpath.

      Specified by:
      createNameMapToAll in interface ServiceFinder
      Parameters:
      serviceName - the service class
      Returns:
      the map

    • getClassLoader

      protected ClassLoader getClassLoader(String serviceName)
      Gets the classloader for the given service name.
      Parameters:
      serviceName - the service name
      Returns:
      the loader, never null

    • parseURL

      protected void parseURL(URL url, String serviceName, Map<String,URL> services)
      Parses a service URL.
      The implementation assumes the provider configuration file in property-file format. This includes the special case of key-only properties which is equivalent to the format used in ServiceLoader.
      Parameters:
      url - the url of the provider definition
      serviceName - the name of the service
      services - the implementing services map

    • parseURLs

      protected void parseURLs(Collection<URL> urls, String serviceName, Map<String,URL> services)
      Parses an enumeration of URLs.
      Parameters:
      urls - the URLs
      serviceName - the service name
      services - the destination map

    • normalizeLine

      protected String normalizeLine(String line)
      Normalizes a line.
      Trailing and leading spaces are ignored. Comments starting with a hash # are stripped. A hash can be escaped by a backslash.
      Parameters:
      line - the source line
      Returns:
      the normalized line, null if line contains no information