/*******************************************************************************
* Copyright (c) 2005, 2007 committers of openArchitectureWare and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* copied from Eclipse (org.eclipse.core.runtime.IProgressMonitor)
* adaptions by Clemens Kadura
*******************************************************************************/
package org.eclipse.emf.mwe.core.monitor;
/**
* The <code>IProgressMonitor</code> interface is implemented by objects that
* monitor the progress of an activity; the methods in this interface are
* invoked by code that performs the activity.
* <p>
* All activity is broken down into a linear sequence of tasks against which
* progress is reported. When a task begins, a <code>beginTask(String, int)
* </code> notification is reported,
* followed by any number and mixture of progress reports (<code>worked()</code>
* ) and subtask notifications (<code>subTask(String)</code>). When the task is
* eventually completed, a <code>done()</code> notification is reported. After
* the <code>done()</code> notification, the progress monitor cannot be reused;
* i.e., <code>
* beginTask(String, int)</code> cannot be called again after the call to
* <code>done()</code>.
* </p>
* <p>
* A request to cancel an operation can be signaled using the
* <code>setCanceled</code> method. Operations taking a progress monitor are
* expected to poll the monitor (using <code>isCanceled</code>) periodically and
* abort at their earliest convenience. Operation can however choose to ignore
* cancelation requests.
* </p>
* <p>
* Since notification is synchronous with the activity itself, the listener
* should provide a fast and robust implementation. If the handling of
* notifications would involve blocking operations, or operations which might
* throw uncaught exceptions, the notifications should be queued, and the actual
* processing deferred (or perhaps delegated to a separate thread).
* </p>
* <p>
* Clients may implement this interface.
* </p>
*/
public interface ProgressMonitor {
/**
* Constant indicating an unknown amount of work.
*/
public final static int UNKNOWN = -1;
/**
* Notifies that the main task is beginning. This must only be called once
* on a given progress monitor instance.
*
* @param name
* the name (or description) of the main task
* @param totalWork
* the total number of work units into which the main task is
* been subdivided. If the value is <code>UNKNOWN</code> the
* implemenation is free to indicate progress in a way which
* doesn't require the total number of work units in advance.
*/
public void beginTask(String name, int totalWork);
/**
* Notifies that the work is done; that is, either the main task is
* completed or the user canceled it. This method may be called more than
* once (implementations should be prepared to handle this case).
*/
public void done();
/**
* Internal method to handle scaling correctly. This method must not be
* called by a client. Clients should always use the method</code>
* worked(int)</code>.
*
* @param work
* the amount of work done
*/
public void internalWorked(double work);
/**
* Returns whether cancelation of current operation has been requested.
* Long-running operations should poll to see if cancelation has been
* requested.
*
* @return <code>true</code> if cancellation has been requested, and
* <code>false</code> otherwise
* @see #setCanceled(boolean)
*/
public boolean isCanceled();
/**
* Sets the cancel state to the given value.
*
* @param value
* <code>true</code> indicates that cancelation has been
* requested (but not necessarily acknowledged);
* <code>false</code> clears this flag
* @see #isCanceled()
*/
public void setCanceled(boolean value);
/**
* Sets the task name to the given value. This method is used to restore the
* task label after a nested operation was executed. Normally there is no
* need for clients to call this method.
*
* @param name
* the name (or description) of the main task
* @see #beginTask(java.lang.String, int)
*/
public void setTaskName(String name);
/**
* Notifies that a subtask of the main task is beginning. Subtasks are
* optional; the main task might not have subtasks.
*
* @param name
* the name (or description) of the subtask
*/
public void subTask(String name);
/**
* Notifies that a given number of work unit of the main task has been
* completed. Note that this amount represents an installment, as opposed to
* a cumulative amount of work done to date.
*
* @param work
* the number of work units just completed
*/
public void worked(int work);
/**
* Notifies that a task will be started. Must be paired together with one
* <code>postTask()</code> call.
*
* @param element
* The element that fired that notification
* @param context
* the context of execution
*/
public void preTask(Object element, Object context);
/**
* Notifies that a task was finished. Must be paired together with one
* <code>preTask()</code> call.
*
* @param element
* The element that fired that notification
* @param context
* the context of execution
*/
public void postTask(Object element, Object context);
/**
* Notifies that overall process was started.
*
* @param element
* The element that fired that notification
* @param context
* the context of execution
*/
public void started(Object element, Object context);
/**
* Notifies that overall process was finished.
*
* @param element
* The element that fired that notification
* @param context
* the context of execution
*/
public void finished(Object element, Object context);
}