com.qrmedia.commons.multispi
Class MultiSpi

java.lang.Object
  com.qrmedia.commons.multispi.MultiSpi

@ThreadSafe
public final class MultiSpi
extends Object

One-stop shop for users of MultiSpi. Instances should be created via dependency injection or using the MultiSpiBuilder.

Since:

4 Dec 2010

Author:

aphillips

See Also:

ServiceLoader

Constructor Summary

MultiSpi(Set<ServiceImplementationProvider> providers)

Method Summary

boolean	equals(Object obj)
Set<String>	findImplementationNames(Class<?> serviceClass) Shorthand for findImplementationNames(serviceClass, defaultClassLoader) where defaultClassLoader is Thread.currentThread().getContextClassLoader() if non-null ClassLoader.getSystemClassLoader() if non-null the bootstrap classloader otherwise
Set<String>	findImplementationNames(Class<?> serviceClass, ClassLoader classpathResourceLoader) Finds the names of classes implementing the requested service, as determined by the available providers.
<S> Set<Class<? extends S>>	findImplementations(Class<S> serviceClass) Shorthand for findImplementations(serviceClass, defaultClassLoader) where defaultClassLoader is Thread.currentThread().getContextClassLoader() if non-null ClassLoader.getSystemClassLoader() if non-null the bootstrap classloader otherwise
<S> Set<Class<? extends S>>	findImplementations(Class<S> serviceClass, ClassLoader implementationLoader) Finds the classes implementing the requested service, as determined by the available providers.
int	hashCode()
<S> Set<S>	loadImplementations(Class<S> serviceClass) Shorthand for loadImplementations(serviceClass, defaultClassLoader).
<S> Set<S>	loadImplementations(Class<S> serviceClass, ClassLoader implementationLoader) Finds the classes implementing the requested service, as determined by the available providers, and loads an instance of each implementation.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiSpi

@Inject
public MultiSpi(@Nonnull
                       Set<ServiceImplementationProvider> providers)

Method Detail

findImplementationNames

@Nonnull
public Set<String> findImplementationNames(@Nonnull
                                                   Class<?> serviceClass)

Shorthand for findImplementationNames(serviceClass, defaultClassLoader) where defaultClassLoader is

• Thread.currentThread().getContextClassLoader() if non-null
• ClassLoader.getSystemClassLoader() if non-null
• the bootstrap classloader otherwise

Parameters:

serviceClass - the class of the service

Returns:

a set of names of classes designated as implementing the requested service

findImplementationNames

@Nonnull
public Set<String> findImplementationNames(@Nonnull
                                                   Class<?> serviceClass,
                                                   @Nonnull
                                                   ClassLoader classpathResourceLoader)

Finds the names of classes implementing the requested service, as determined by the available providers.

Note that individual providers may or may not guarantee that the classes returned actually implement the interface!

Parameters:

serviceClass - the class of the service

classpathResourceLoader - the class loader to be used to locate classpath resources

Returns:

a set of names of classes designated as implementing the requested service

findImplementations

@Nonnull
public <S> Set<Class<? extends S>> findImplementations(@Nonnull
                                                               Class<S> serviceClass)
                                            throws ClassCastException,
                                                   ClassNotFoundException

Shorthand for findImplementations(serviceClass, defaultClassLoader) where defaultClassLoader is

• Thread.currentThread().getContextClassLoader() if non-null
• ClassLoader.getSystemClassLoader() if non-null
• the bootstrap classloader otherwise

Type Parameters:

S - the type of the service

Parameters:

serviceClass - the class of the service

Returns:

a set of classes of implementations of the service

Throws:

ClassCastException - if any of the classes are not actually implementations of the requested service

ClassNotFoundException - if any of the classes cannot be loaded

See Also:

findImplementations(Class, ClassLoader)

findImplementations

@Nonnull
public <S> Set<Class<? extends S>> findImplementations(@Nonnull
                                                               Class<S> serviceClass,
                                                               @Nonnull
                                                               ClassLoader implementationLoader)
                                            throws ClassCastException,
                                                   ClassNotFoundException

Finds the classes implementing the requested service, as determined by the available providers.

This method will check whether the classes found do, in fact, implement the requested service, and a ClassCastException will be thrown if any of the classes does not.

If more lenient behaviour is desired (e.g. skipping any classes that cannot be found, or do not actually implement the interface), use findImplementationNames(Class) instead.

Type Parameters:

S - the type of the service

Parameters:

serviceClass - the class of the service

implementationLoader - the class loader to be used to attempt to load the classes

Returns:

a set of instances of implementations of the service

Throws:

ClassCastException - if any of the classes are not actually implementations of the requested service

ClassNotFoundException - if any of the classes cannot be loaded

See Also:

findImplementations(Class)

loadImplementations

@Nonnull
public <S> Set<S> loadImplementations(@Nonnull
                                              Class<S> serviceClass)
                           throws ClassNotFoundException,
                                  InstantiationException

Shorthand for loadImplementations(serviceClass, defaultClassLoader). where defaultClassLoader is

• Thread.currentThread().getContextClassLoader() if non-null
• ClassLoader.getSystemClassLoader() if non-null
• the bootstrap classloader otherwise

Type Parameters:

S - the type of the service

Parameters:

serviceClass - the class of the service

Returns:

a set of instances of implementations of the service

Throws:

ClassNotFoundException - if any of the classes cannot be loaded

InstantiationException - if any of the classes are not actually implementations of the requested service, or cannot be instantiated using a public no-argument constructor

See Also:

loadImplementations(Class, ClassLoader)

loadImplementations

@Nonnull
public <S> Set<S> loadImplementations(@Nonnull
                                              Class<S> serviceClass,
                                              @Nonnull
                                              ClassLoader implementationLoader)
                           throws ClassNotFoundException,
                                  InstantiationException

Finds the classes implementing the requested service, as determined by the available providers, and loads an instance of each implementation.

This method will check whether the classes found do, in fact, implement the requested service, and an InstantiationException will be thrown if any of the classes does not.

Service classes are expected to provide a public, no-argument constructor, which will be invoked to create instances of the implementation classes found. An InstantiationException is thrown if the class cannot be instantiated.

If more lenient behaviour is desired (e.g. skipping any classes that cannot be found, or do not actually implement the interface), use findImplementationNames(Class) instead.

Type Parameters:

S - the type of the service

Parameters:

serviceClass - the class of the service

implementationLoader - the class loader to be used to attempt to load the classes

Returns:

a set of instances of implementations of the service

Throws:

ClassNotFoundException - if any of the classes cannot be loaded

InstantiationException - if any of the classes are not actually implementations of the requested service, or cannot be instantiated using a public no-argument constructor

See Also:

loadImplementations(Class)

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object