InitializationErrorInvocationHandler.java

package hudson.util.jna;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * {@link InvocationHandler} that reports the same exception over and over again when methods are invoked
 * on the interface.
 *
 * This is convenient to remember why the initialization of the real JNA proxy failed.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.487
 * @see <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7199848">Related bug report against JDK</a>
 */
public class InitializationErrorInvocationHandler
    implements InvocationHandler
{
    //~ Instance fields --------------------------------------------------------

    private final Throwable cause;

    //~ Constructors -----------------------------------------------------------

    private InitializationErrorInvocationHandler (Throwable cause)
    {
        this.cause = cause;
    }

    //~ Methods ----------------------------------------------------------------

    public static <T> T create (Class<T>  type,
                                Throwable cause)
    {
        return type.cast(
            Proxy.newProxyInstance(
                type.getClassLoader(),
                new Class[] { type },
                new InitializationErrorInvocationHandler(cause)));
    }

    @Override
    public Object invoke (Object   proxy,
                          Method   method,
                          Object[] args)
        throws Throwable
    {
        if (method.getDeclaringClass() == Object.class) {
            return method.invoke(this, args);
        }

        throw new UnsupportedOperationException(
            "Failed to link the library: " + method.getDeclaringClass(),
            cause);
    }
}