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| <title>Long-running operations</title> |
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| <h2> |
| Long-running operations</h2> |
| <p> |
| The <b><a |
| href="../reference/api/org/eclipse/jface/operation/package-summary.html"> |
| org.eclipse.jface.operations</a></b> package defines interfaces for |
| long-running operations that require progress indicators or allow user |
| cancellation of the operation. These interfaces are used in the implementation |
| of the workbench progress dialogs and views.</p> |
| <p>In general, plug-ins should use the workbench support provided in |
| <a href="../reference/api/org/eclipse/ui/progress/IProgressService.html"><b>IProgressService</b></a> |
| for running long operations, so that all plug-ins will have a consistent presentation |
| of progress. See <a href="workbench_jobs.htm">Workbench Concurrency Support</a> for |
| a complete discussion of the available support for progress dialogs and views. The remainder |
| of this discussion highlights the details of the JFace operations infrastructure which is |
| used by the workbench.</p> |
| <h3>Runnables and progress</h3> |
| <p> |
| The platform runtime defines a common interface, <b><a |
| href="../reference/api/org/eclipse/core/runtime/IProgressMonitor.html">IProgressMonitor</a></b>, |
| which is used to report progress to the user while long running |
| operations are in progress. The client can provide a monitor as a |
| parameter in many platform API methods when it is important to show |
| progress to the user.</p> |
| <p>JFace defines more specific interfaces for objects that implement |
| the user interface for a progress monitor. </p> |
| <p> |
| <b><a |
| href="../reference/api/org/eclipse/jface/operation/IRunnableWithProgress.html"> |
| IRunnableWithProgress</a></b> is the interface for a long-running |
| operation. The <b>run</b> |
| method for this interface has an <b><a |
| href="../reference/api/org/eclipse/core/runtime/IProgressMonitor.html">IProgressMonitor</a> |
| </b>parameter that is used to report progress and check for user |
| cancelation.</p> |
| <p><a |
| href="../reference/api/org/eclipse/jface/operation/IRunnableContext.html"><b>IRunnableContext</b></a> |
| is the interface for the different places in the UI where progress can |
| be |
| reported. Classes that implement this interface may choose to use |
| different techniques for showing progress and running the |
| operation. |
| For example, <b><a |
| href="../reference/api/org/eclipse/jface/dialogs/ProgressMonitorDialog.html">ProgressMonitorDialog</a></b> |
| implements this interface by showing a progress dialog. <b><a |
| href="../reference/api/org/eclipse/ui/IWorkbenchWindow.html">IWorkbenchWindow</a></b> |
| implements this interface by showing progress in the workbench window's |
| status |
| line. <a |
| href="../reference/api/org/eclipse/jface/wizard/WizardDialog.html"><b>WizardDialog</b></a> |
| implements this interface to show long running operations inside the wizard status line.</p> |
| |
| <blockquote><i>Note: The workbench UI provides additional support for operations in <b><a |
| href="../reference/api/org/eclipse/ui/actions/WorkspaceModifyOperation.html">WorkspaceModifyOperation</a></b>. |
| This class simplifies the implementation of long-running operations that modify the workspace. It maps between <a |
| href="../reference/api/org/eclipse/jface/operation/IRunnableWithProgress.html"><b>IRunnableWithProgress</b></a> |
| and <a href="../reference/api/org/eclipse/core/resources/IWorkspaceRunnable.html"><b>IWorkspaceRunnable</b></a>. |
| See the javadoc for further detail.</i></blockquote> |
| |
| <h3>Modal operations</h3> |
| <p> |
| The <b><a |
| href="../reference/api/org/eclipse/jface/operation/ModalContext.html"> |
| ModalContext</a></b> class is provided to run an operation that is |
| modal from the client code's perspective. |
| It is used inside the different implementations of <a |
| href="../reference/api/org/eclipse/jface/operation/IRunnableContext.html"><b>IRunnableContext</b></a>. |
| If your plug-in needs to wait on the completion of a long-running |
| operation before continuing |
| execution, <b><a |
| href="../reference/api/org/eclipse/jface/operation/ModalContext.html">ModalContext</a></b> |
| can be used to accomplish this while still keeping the user interface |
| responsive.</p> |
| <p> |
| When you run an operation in a modal context, you can choose to fork |
| the operation in a different thread. If |
| <b>fork</b> is false, the operation will be run in the |
| calling thread. If <b>fork</b> is true, the |
| operation will be run in a new thread, the calling thread will be |
| blocked, and |
| the UI event loop will be run until the operation |
| terminates. </p> |
| <p> |
| For more information on the UI event loop, see <a class="XRef" |
| href="swt_threading.htm"> Threading issues for clients</a>.<br> |
| </p> |
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