--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationApprover.d	Sat Mar 14 18:23:29 2009 +0100
@@ -0,0 +1,110 @@
+/*******************************************************************************
+ * Copyright (c) 2005 IBM Corporation 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:
+ *     IBM Corporation - initial API and implementation
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module org.eclipse.core.commands.operations.IOperationApprover;
+
+import org.eclipse.core.runtime.IAdaptable;
+import org.eclipse.core.runtime.IStatus;
+
+import org.eclipse.core.commands.operations.IUndoableOperation;
+import org.eclipse.core.commands.operations.IOperationHistory;
+
+import java.lang.all;
+
+/**
+ * <p>
+ * IOperationApprover defines an interface for approving the undo or redo of a
+ * particular operation within an operation history. Operations that are
+ * candidates for undo or redo have already been validated against their current
+ * state and according to the rules of the history.
+ * </p>
+ * <p>
+ * By the time an IOperationApprover is consulted, the undo has already been
+ * requested. Approvers should return an <code>IStatus</code> object with
+ * severity <code>OK</code> if the operation should proceed, and any other
+ * severity if it should not. When an operation is not approved, it is expected
+ * that the object not allowing the operation has already consulted the user if
+ * necessary or otherwise provided any necessary information to the user about
+ * the fact that the operation is not approved.
+ * </p>
+ * <p>
+ * Operation approvers must be prepared to receive the approval messages from a
+ * background thread. Any UI access occurring inside the implementation must be
+ * properly synchronized using the techniques specified by the client's widget
+ * library.
+ * </p>
+ *
+ * @since 3.1
+ */
+public interface IOperationApprover {
+
+    /**
+     * Return a status indicating whether the specified operation should be
+     * redone. Any status that does not have severity <code>IStatus.OK</code>
+     * will not be approved. Implementers should not assume that the redo will
+     * be performed when the status is <code>OK</code>, since other operation
+     * approvers may veto the redo.
+     *
+     * @param operation
+     *            the operation to be redone
+     * @param history
+     *            the history redoing the operation
+     * @param info
+     *            the IAdaptable (or <code>null</code>) provided by the
+     *            caller in order to supply UI information for prompting the
+     *            user if necessary. When this parameter is not
+     *            <code>null</code>, it should minimally contain an adapter
+     *            for the org.eclipse.swt.widgets.Shell.class. Even if UI
+     *            information is provided, the implementation of this method
+     *            must be prepared for being called from a background thread.
+     *            Any UI access must be properly synchronized using the
+     *            techniques specified by the client's widget library.
+     * @return the IStatus describing whether the operation is approved. The
+     *         redo will not proceed if the status severity is not
+     *         <code>OK</code>, and the caller requesting the redo will be
+     *         returned the status that caused the rejection. Any other status
+     *         severities will not be interpreted by the history.
+     */
+    IStatus proceedRedoing(IUndoableOperation operation,
+            IOperationHistory history, IAdaptable info);
+
+    /**
+     * Return a status indicating whether the specified operation should be
+     * undone. Any status that does not have severity <code>IStatus.OK</code>
+     * will not be approved. Implementers should not assume that the undo will
+     * be performed when the status is <code>OK</code>, since other operation
+     * approvers can veto the undo.
+     *
+     * @param operation
+     *            the operation to be undone
+     * @param history
+     *            the history undoing the operation
+     * @param info
+     *            the IAdaptable (or <code>null</code>) provided by the
+     *            caller in order to supply UI information for prompting the
+     *            user if necessary. When this parameter is not
+     *            <code>null</code>, it should minimally contain an adapter
+     *            for the org.eclipse.swt.widgets.Shell.class. Even if UI
+     *            information is provided, the implementation of this method
+     *            must be prepared for being called from a background thread.
+     *            Any UI access must be properly synchronized using the
+     *            techniques specified by the client's widget library.
+     * @return the IStatus describing whether the operation is approved. The
+     *         undo will not proceed if the status severity is not
+     *         <code>OK</code>, and the caller requesting the undo will be
+     *         returned the status that caused the rejection. Any other status
+     *         severities will not be interpreted by the history.
+     */
+    IStatus proceedUndoing(IUndoableOperation operation,
+            IOperationHistory history, IAdaptable info);
+
+}