javax.websocket.ContainerProvider Maven / Gradle / Ivy
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package javax.websocket;
import java.util.ServiceLoader;
/**
* Provider class that allows the developer to get a reference to
* the implementation of the WebSocketContainer.
* The provider class uses the
* ServiceLoader
* to load an implementation of ContainerProvider. Specifically, the fully qualified classname
* of the container implementation of ContainerProvider must be listed in the
* META-INF/services/javax.websocket.ContainerProvider file in the implementation JAR file.
*
* @author dannycoward
*/
public abstract class ContainerProvider {
/**
* Obtain a new instance of a WebSocketContainer. The method looks for the
* ContainerProvider implementation class in the order listed in the META-INF/services/javax.websocket.ContainerProvider
* file, returning the WebSocketContainer implementation from the ContainerProvider implementation
* that is not {@code null}.
* @return an implementation provided instance of type WebSocketContainer
*/
public static WebSocketContainer getWebSocketContainer() {
WebSocketContainer wsc = null;
for (ContainerProvider impl : ServiceLoader.load(ContainerProvider.class)) {
wsc = impl.getContainer();
if (wsc != null) {
return wsc;
}
}
if (wsc == null) {
throw new RuntimeException("Could not find an implementation class.");
} else {
throw new RuntimeException("Could not find an implementation class with a non-null WebSocketContainer.");
}
}
/**
* Load the container implementation.
* @return the implementation class
*/
protected abstract WebSocketContainer getContainer();
}