org.opencastproject.workflow.handler.ResumableWorkflowOperationHandlerBase.java Source code

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Here is the source code for org.opencastproject.workflow.handler.ResumableWorkflowOperationHandlerBase.java

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/**
 *  Copyright 2009, 2010 The Regents of the University of California
 *  Licensed under the Educational Community License, Version 2.0
 *  (the "License"); you may not use this file except in compliance
 *  with the License. You may obtain a copy of the License at
 *
 *  http://www.osedu.org/licenses/ECL-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an "AS IS"
 *  BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 *  or implied. See the License for the specific language governing
 *  permissions and limitations under the License.
 *
 */
package org.opencastproject.workflow.handler;

import org.opencastproject.job.api.JobContext;
import org.opencastproject.rest.RestConstants;
import org.opencastproject.rest.StaticResource;
import org.opencastproject.workflow.api.AbstractWorkflowOperationHandler;
import org.opencastproject.workflow.api.ResumableWorkflowOperationHandler;
import org.opencastproject.workflow.api.WorkflowInstance;
import org.opencastproject.workflow.api.WorkflowOperationException;
import org.opencastproject.workflow.api.WorkflowOperationResult;
import org.opencastproject.workflow.api.WorkflowOperationResult.Action;

import org.apache.commons.io.FilenameUtils;
import org.osgi.framework.ServiceRegistration;
import org.osgi.service.component.ComponentContext;

import java.util.Dictionary;
import java.util.Hashtable;
import java.util.Map;

import javax.servlet.Servlet;

/**
 * Abstract base implementation for a resumable operation handler, which implements a simple operations for starting an
 * operation, returning a {@link WorkflowOperationResult} with the current mediapackage and {@link Action#PAUSE} and
 * resuming an operation, returning a {@link WorkflowOperationResult} with the current mediapackage and
 * {@link Action#CONTINUE}.
 */
public class ResumableWorkflowOperationHandlerBase extends AbstractWorkflowOperationHandler
        implements ResumableWorkflowOperationHandler {

    /** OSGi component context, obtained during component activation */
    protected ComponentContext componentContext = null;

    /** Reference to the static resource service */
    protected ServiceRegistration staticResourceRegistration = null;

    /** The static resource representing the hold state ui */
    protected StaticResource staticResource = null;

    /** Title of this hold state */
    protected String holdActionTitle = null;

    private static final String DEFAULT_TITLE = "Action";

    /**
     * {@inheritDoc}
     * 
     * @see org.opencastproject.workflow.api.AbstractWorkflowOperationHandler#activate(org.osgi.service.component.ComponentContext)
     */
    public void activate(ComponentContext componentContext) {
        this.componentContext = componentContext;
        super.activate(componentContext);
    }

    /**
     * Callback from the OSGi environment on component shutdown. Make sure to call this super implementation when
     * overwriting this class.
     */
    public void deactivate() {
        if (staticResourceRegistration != null)
            staticResourceRegistration.unregister();
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.opencastproject.workflow.api.ResumableWorkflowOperationHandler#getHoldStateUserInterfaceURL(org.opencastproject.workflow.api.WorkflowInstance)
     */
    public String getHoldStateUserInterfaceURL(WorkflowInstance workflowInstance)
            throws WorkflowOperationException {
        if (staticResource == null)
            return null;
        return staticResource.getDefaultUrl();
    }

    /**
     * Sets the title that is displayed on the hold state ui.
     * 
     * @param title
     *          the title
     */
    protected void setHoldActionTitle(String title) {
        this.holdActionTitle = title;
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.opencastproject.workflow.api.ResumableWorkflowOperationHandler#getHoldActionTitle()
     */
    public String getHoldActionTitle() {
        if (holdActionTitle == null) {
            return DEFAULT_TITLE;
        } else {
            return holdActionTitle;
        }
    }

    /**
     * Registers the resource identified by <code>resourcePath</code> as the ui to be displayed during hold.
     * 
     * @param resourcePath
     *          the path to the resource
     * @return the URL that was created when registering the resource
     */
    protected String registerHoldStateUserInterface(final String resourcePath) {
        String alias = "/workflow/hold/" + getClass().getName().toLowerCase();
        if (resourcePath == null)
            throw new IllegalArgumentException("Classpath must not be null");
        String path = FilenameUtils.getPathNoEndSeparator(resourcePath);
        String welcomeFile = FilenameUtils.getName(resourcePath);
        staticResource = new StaticResource(getClass().getClassLoader(), path, alias, welcomeFile);
        Dictionary<String, String> props = new Hashtable<String, String>();
        props.put("contextId", RestConstants.HTTP_CONTEXT_ID);
        props.put("alias", alias);
        staticResourceRegistration = componentContext.getBundleContext().registerService(Servlet.class.getName(),
                staticResource, props);
        return staticResource.getDefaultUrl();
    }

    /**
     * {@inheritDoc}
     * 
     * This default implementation will put the workflow into the hold state.
     * 
     * @see org.opencastproject.workflow.api.AbstractWorkflowOperationHandler#start(org.opencastproject.workflow.api.WorkflowInstance,
     *      JobContext)
     */
    @Override
    public WorkflowOperationResult start(WorkflowInstance workflowInstance, JobContext context)
            throws WorkflowOperationException {
        return createResult(Action.PAUSE);
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.opencastproject.workflow.api.ResumableWorkflowOperationHandler#resume(org.opencastproject.workflow.api.WorkflowInstance,
     *      JobContext, java.util.Map)
     */
    @Override
    public WorkflowOperationResult resume(WorkflowInstance workflowInstance, JobContext context,
            Map<String, String> properties) throws WorkflowOperationException {
        return createResult(Action.CONTINUE);
    }

    @Override
    public boolean isAlwaysPause() {
        return false;
    }
}