Class ObjectFactory<T>

java.lang.Object
uk.ac.starlink.util.ObjectFactory<T>

public class ObjectFactory<T> extends Object
Manages dynamic creation of objects from a known set of classes. An ObjectFactory keeps a list of classes with associated nicknames; the idea is that you can obtain an instance of a given class by supplying the nickname in question. Instead of a nickname you can use the fully qualified classname, whether or not it has previously been registered. Any class registered must be a subclass of the superclass specified when this factory is constructed, and must have a no-arg constructor.
Since:
10 Aug 2005
Author:
Mark Taylor
  • Constructor Details

    • ObjectFactory

      public ObjectFactory(Class<T> clazz)
      Constructor.
      Parameters:
      clazz - type which must be a supertype of any class registered with this factory
  • Method Details

    • getFactoryClass

      public Class<T> getFactoryClass()
      Returns the class of which any object created by this factory is guaranteed to be an instance.
      Returns:
      clazz
    • register

      public void register(String nickName, String className)
      Registers a class with its nickname.
      Parameters:
      nickName - nickname
      className - fully-qualified class name
    • getNickNames

      public String[] getNickNames()
      Returns a list of the nicknames which have been registered.
      Returns:
      nickname array
    • isRegistered

      public boolean isRegistered(String name)
      Indicates whether this factory knows about a given name. This may either be a registered nickname or a fully qualified classname for a class which is a subclass of this factory's produced class.
      Parameters:
      name - name
      Returns:
      true iff name can sensibly be passed to createObject(java.lang.String)
    • createObject

      public T createObject(String spec) throws LoadException
      Constructs and returns an object from one of the classes registered with this factory. If construction fails because the required class is not on the classpath or there is some error in class initialization, a LoadException is thrown. If the class is of the wrong sort (has no no-arg constructor, is not a subtype of this factory's supertype) a RuntimeException will be thrown.
      Parameters:
      spec - classname/nickname of class to instantiate, followed by optional config text
      Throws:
      LoadException - if the load fails for unsurprising reasons
      See Also: