/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.jboss.as.controller;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import org.jboss.dmr.ModelNode;
import org.jboss.msc.service.ServiceController;
import org.jboss.msc.service.StabilityMonitor;

/**
 * Base class for operations that do nothing in {@link org.jboss.as.controller.OperationContext.Stage#MODEL} except
 * register a {@link org.jboss.as.controller.OperationContext.Stage#RUNTIME} step.
 *
 * @author Brian Stansberry (c) 2011 Red Hat Inc.
 * @author <a href="mailto:ropalka@redhat.com">Richard Opalka</a>
 */
public abstract class AbstractRuntimeOnlyHandler implements OperationStepHandler {


    /**
     * Wait for the required service to start up and fail otherwise. This method is necessary when a runtime operation
     * uses a service that might have been created within a composite operation.
     *
     * This method will wait at most 100 millis.
     *
     * @param controller the service to wait for
     * @throws OperationFailedException if the service is not available, or the thread was interrupted.
     *
     * @deprecated this method is unrelated to this class and will be removed in the next major release
     */
    @Deprecated
    public void waitFor(final ServiceController<?> controller) throws OperationFailedException {
        if (controller.getState() == ServiceController.State.UP) return;

        final StabilityMonitor monitor = new StabilityMonitor();
        monitor.addController(controller);
        try {
            monitor.awaitStability(100, MILLISECONDS);
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt();
            throw new OperationFailedException((new ModelNode()).set("Interrupted waiting for service: " + controller.getName()));
        } finally {
            monitor.removeController(controller);
        }

        if (controller.getState() != ServiceController.State.UP) {
            throw new OperationFailedException(new ModelNode().set("Required service is not available: " + controller.getName()));
        }
    }

    /**
     * Simply adds a {@link org.jboss.as.controller.OperationContext.Stage#RUNTIME} step that calls
     * {@link #executeRuntimeStep(OperationContext, ModelNode)}.
     *
     * {@inheritDoc}
     */
    @Override
    public void execute(OperationContext context, ModelNode operation) throws OperationFailedException {
        context.addStep(new OperationStepHandler() {
            @Override
            public void execute(OperationContext context, ModelNode operation) throws OperationFailedException {
                // make sure the resource exists before executing a runtime operation.
                // if that's not the case, the operation will report an error with a comprehensive failure
                // description instead of a subsequent exception (such as a NPE).
                if (resourceMustExist(context, operation)) {
                    context.readResource(PathAddress.EMPTY_ADDRESS, false);
                }
                executeRuntimeStep(context, operation);
            }
        }, OperationContext.Stage.RUNTIME);

        context.stepCompleted();
    }

    /**
     * By default the handler will check whether the resource exist before calling @{link #executeRuntimeStep(OperationContext, ModelNode)}.
     *
     * This method can be overridden in the special case where a runtime operation must be executed without a corresponding resource.
     *
     * @return true if the resource must exist for this runtime handler to be executed.
     *
     * @param context the operation context
     * @param operation the operation being executed
     */
    protected boolean resourceMustExist(OperationContext context, ModelNode operation) {
        return true;
    }

    /**
     * Execute this step in {@link org.jboss.as.controller.OperationContext.Stage#RUNTIME}.
     * If the operation fails, {@link OperationContext#getFailureDescription() context.getFailureDescroption()}
     * must be called, or {@link OperationFailedException} must be thrown, before calling one of the
     * {@link org.jboss.as.controller.OperationContext#completeStep(OperationContext.ResultHandler) context.completeStep variants}.
     * If the operation succeeded, {@link OperationContext#getResult() context.getResult()} should
     * be called and the result populated with the outcome, after which one of the
     * {@link org.jboss.as.controller.OperationContext#completeStep(OperationContext.ResultHandler) context.completeStep variants}
     * must be called.
     *
     * @param context the operation context
     * @param operation the operation being executed
     * @throws OperationFailedException if the operation failed <b>before</b> calling {@code context.completeStep()}
     */
    protected abstract void executeRuntimeStep(OperationContext context, ModelNode operation) throws OperationFailedException;

}
