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#ifndef __com_sun_star_document_XUndoManager_idl__
#define __com_sun_star_document_XUndoManager_idl__

#include <com/sun/star/document/EmptyUndoStackException.idl>
#include <com/sun/star/document/UndoContextNotClosedException.idl>
#include <com/sun/star/document/UndoFailedException.idl>
#include <com/sun/star/util/InvalidStateException.idl>
#include <com/sun/star/util/XLockable.idl>
#include <com/sun/star/container/XChild.idl>
#include <com/sun/star/lang/IllegalArgumentException.idl>
#include <com/sun/star/lang/WrappedTargetException.idl>

//==================================================================================================================

module com { module sun { module star { module document { 

interface XUndoAction;
interface XUndoManagerListener;

//==================================================================================================================

/** provides access to the undo/redo stacks of a document

    <h3>Undo</h3>
    <p>Changes to a document usually result in recording of information how to undo those changes, if desired. A so-called
    undo action records the information how to undo a single change. Undo actions are maintained in a stack, so that
    the changes they represent can be undo in the reverse order they have originally been applied.</p>

    <h3>Redo</h3>
    <p>Additionally, the Undo manager manages a Redo stack: Actions which are undone are moved from the Undo to the Redo
    stack, so it is possible to re-apply the changes to the document.</p>

    <h3>Undo contexts</h3>
    <p>For collecting multiple changes in a single undo action, so-called Undo contexts are provided. When an Undo
    context is entered, all subsequently added Undo actions are not pushed onto the undo stack directly, but considered
    a sub action of the Undo context. Once the Undo context is left, a single undo action is pushed onto the undo stack,
    which comprises all those single Undo actions.<br/>
    Undo contexts can be arbitrarily nested.</p>

    <h3>Hidden Undo actions</h3>
    <p>Hidden Undo actions are those which in no observable way contribute to the undo stack. That is,
    any method retrieving information about the stack will behave as if the undo action does not exist. Nonetheless,
    calling <member>undo</member> respectively <member>redo</member> will include those actions.<br/>
    Hidden Undo actions can be created by calling <member>enterHiddenUndoContext</member>, following by
    <member>leaveUndoContext</member>.</p>

    <a name="locking"></a>
    <h3>Locking</h3>
    <p>An Undo manager can be locked and unlocked, using the <member>XLockable::lock</member> and
    <member>XLockable::unlock</member> methods. When it is locked, then every attempt to add an undo action, or to
    enter or leave an Undo context, will be silently ignored.</p>
 */
interface XUndoManager
{
    /** allows <a href="#locking">locking</a> the undo manager.
    */
    interface ::com::sun::star::util::XLockable;

    /** allows accessing the component, usually a document, which the undo manager works for.

        <p><member scope="com::sun::star::container">XChild::setParent</member> is not supported, and will throw
        an <type scope="com::sun::star::lang">NoSupportException</type>.</p>
    */
    interface ::com::sun::star::container::XChild;

    /** enters a new undo context.

        <p>A new undo action will be added to the undo stack, with the title given as <code>i_title</code>. As long
        as the context is not left, every undo action added to the stack will be treated as sub action. This means
        it will not be directly accessible at the Undo manager, not appear in any user interface, and cannot be
        separately undone or re-done.</p>

        <p>Each call to <code>enterUndoContext</code> must be paired by a call to <member>leaveUndoContext</member>,
        otherwise, the document's undo stack is left in an inconsistent state.</p>

        <p>Undo contexts can be nested, i.e. it is legitimate to call <code>enterUndoContext</code> and
        <member>enterHiddenUndoContext</member> multiple times without calling <member>leaveUndoContext</member> inbetween.</p>

        @see leaveUndoContext
    */
    void    enterUndoContext(
                [in] string i_title
            );

    /** enters a new undo context, creating a hidden undo action.

        <p>A hidden undo action does not, in any visible way, contribute to the undo stack. This means
        that
        <ul><li>Calling <member>undo</member> when the top-element is a hidden undo action will transparently
                undo this action, and also undo the new top element of the stack.</li>
            <li>Calling <member>redo</member> when the top-element is a hidden action will transparently
                redo this action, and also redo the new top element of the stack.</li>
            <li>In any user interface presenting the current Undo or Redo actions to the user, a hidden
                action will not be listed.</p>
        </ul>

        <p>A new undo action will be added to the undo stack. As long as the context is not left, every undo action
        added to the stack will be treated as sub action. This means it will not be directly accessible at the undo
        manager, not appear in any user interface, and cannot be separately undone or re-done.</p>

        <p>Each call to <code>enterHiddenUndoContext</code> must be paired by a call to <member>leaveUndoContext</member>,
        otherwise, the document's undo stack is left in an inconsistent state.</p>

        <p>Undo contexts can be nested, i.e. it is legitimate to call <member>enterUndoContext</member> and
        <code>enterHiddenUndoContext</code> multiple times without calling <member>leaveUndoContext</member> inbetween.</p>

        @throws EmptyUndoStackException
            if the undo stack is currently empty, in which case it is impossible to push a hidden undo action onto
            it.

        @see enterUndoContext
        @see leaveUndoContext
    */
    void    enterHiddenUndoContext()
        raises( EmptyUndoStackException );

    /** leaves the undo context previously opened via <member>enterUndoContext</member> respectively
        <member>enterHiddenUndoContext</member>.

        <p>If no undo action has been added since the context has been opened, the context is not only left,
        but silently removed, and does not contribute to the undo stack at all. In this case, possible
        listeners will be notified via <member>XUndoManagerListener::cancelledContext</member>.</p>

        <p>Otherwise, the undo context will be closed, and added to the Undo stack; the redo stack will be cleared,
        and listeners will be notified via <member>XUndoManagerListener::leftContext</member> resp.
        <member>XUndoManagerListener::leftHiddenContext</member></p>

        @throws ::com::sun::star::util::InvalidStateException
            if no undo context is currently open.

        @see enterUndoContext
        @see enterHiddenUndoContext
    */
    void    leaveUndoContext()
        raises( ::com::sun::star::util::InvalidStateException );

    /** adds the given undo action to the undo stack.

        <p>The redo stack is cleared when a new action is pushed onto the undo stack.</p>

        <p>The Undo manager takes ownership of any actions pushed onto the undo stack. This means that if the
        action is finally removed from the Undo manager's control (e.g. by calling <member>clear</member> resp.
        <member>clearRedo</member>), it will be disposed, as long as it supports the <member scope="com::sun::star::lang">XComponent</member>
        interface.</p>

        <p>If the Undo manager is <a href="#locking">locked</a> at the moment the method is called, the call will be ignored, and the undo action
        will immediately be disposed, if applicable.</p>

        @throws ::com::sun::star::lang::IllegalArgumentException
            if the given undo action is <NULL/>.
    */
    void    addUndoAction(
                [in] XUndoAction i_action
            )
            raises( ::com::sun::star::lang::IllegalArgumentException );

    /** reverts the most recent action on the document.

        <p>Effectively, invoking this method will
        <ul><li>invoke <member>XUndoAction::undo</member> on the top-most action of the undo stack</li>
            <li>move this undo action from the undo stack to the redo stack</li>
        </ul></p>

        @throws EmptyUndoStackException
            if the undo stack is currently empty

        @throws UndoContextNotClosedException
            if there currently is an open undo context

        @throws UndoFailedException
            if the invocation of <member>XUndoAction::undo</member> raised this exception. In this case, the undo stack
            of the undo manager will have been cleared.

        @see redo
        @see enterUndoContext
    */
    void    undo()
            raises( ::com::sun::star::document::EmptyUndoStackException,
                    ::com::sun::star::document::UndoContextNotClosedException,
                    ::com::sun::star::document::UndoFailedException );

    /** replays the action on the document which has most recently been undone

        <p>Effectively, invoking this method will
        <ul><li>invoke <member>XUndoAction::redo</member> on the top-most action of the redo stack</li>
            <li>move this action from the redo stack to the undo stack</li>
        </ul></p>

        @throws EmptyUndoStackException
            when the Redo stack is currently empty

        @throws UndoContextNotClosedException
            if there currently is an open undo context

        @throws UndoFailedException
            if the invocation of <member>XUndoAction::redo</member> raised this exception. In this case, the redo stack
            of the undo manager will have been cleared.

        @see undo
    */
    void    redo()
            raises( ::com::sun::star::document::EmptyUndoStackException,
                    ::com::sun::star::document::UndoContextNotClosedException,
                    ::com::sun::star::document::UndoFailedException );

    /** determines whether <member>undo</member> can reasonably be expected to succeed.

        @return
            <FALSE/> if and only if the undo stack is currently empty, or there is an open and not-yet-closed
            undo context.
    */
    boolean isUndoPossible();

    /** determines whether <member>redo</member> can reasonably be expected to succeed.

        @return
            <FALSE/> if and only if the redo stack is currently empty, or there is an open and not-yet-closed
            undo context.
    */
    boolean isRedoPossible();

    /** returns the title of the top-most action on the undo stack

        @throws EmptyUndoStackException
            when the undo stack is currently empty

        @see XUndoAction::Title
    */
    string  getCurrentUndoActionTitle()
            raises( ::com::sun::star::document::EmptyUndoStackException );

    /** returns the title of the top-most action on the Redo stack

        @throws EmptyUndoStackException
            when the Redo stack is currently empty
        @see XUndoAction::Title
    */
    string  getCurrentRedoActionTitle()
            raises( ::com::sun::star::document::EmptyUndoStackException );

    /** returns the titles of all actions currently on the undo stack, from top to bottom
        @see XUndoAction::Title
    */
    sequence< string >
            getAllUndoActionTitles();

    /** returns the titles of all actions currently on the Redo stack, from top to bottom

        @see XUndoAction::Title
    */
    sequence< string >
            getAllRedoActionTitles();

    /** clears the undo and the redo stack.

        <p>All actions will be removed from both the Undo and the Redo stack. Actions which implement the
        <type scope="com::sun::star::lang">XComponent</type> interface will be disposed.</p>

        @throws UndoContextNotClosedException
            if the method is invoked while an undo context is still open
    */
    void    clear()
            raises( ::com::sun::star::document::UndoContextNotClosedException );

    /** clears the redo stack.

        <p>All actions will be removed from the Redo stack. Actions which implement the <type scope="com::sun::star::lang">XComponent</type>
        interface will be disposed.</p>

        @throws UndoContextNotClosedException
            if the method is invoked while an undo context is still open
    */
    void    clearRedo()
            raises( ::com::sun::star::document::UndoContextNotClosedException );

    /** resets the Undo manager

        <p>In particular, this method will
            <ul><li>remove all locks from the undo manager</li>
                <li>close all open undo contexts</li>
                <li>clear the undo stack</li>
                <li>clear the redo stack</li>
            </ul></p>

        <p>Note that possible listeners will not get notifications for the single parts of the reset, i.e. there
        will be no single <member>XUndoManagerListener::allActionsCleared</member>,
        <member>XUndoManagerListener::leftContext</member>, etc., notifications. Instead, listeners will be
        notified of the reset by calling their <member>XUndoManagerListener::resetAll</member> method.</p>
    */
    void    reset();

    /** adds a listener to be notified of changes in the Undo/Redo stacks.
    */
    void    addUndoManagerListener(
                [in] XUndoManagerListener i_listener
            );

    /** removes a previously added listener
    */
    void    removeUndoManagerListener(
                [in] XUndoManagerListener i_listener
            );
};

//==================================================================================================================

}; }; }; };

//==================================================================================================================

#endif
