plasma-workspace/libtaskmanager/abstractgroupingstrategy.h

/*****************************************************************

Copyright 2008 Christian Mollekopf <chrigi_1@hotmail.com>

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******************************************************************/

#ifndef ABSTRACTGROUPINGSTRATEGY_H
#define ABSTRACTGROUPINGSTRATEGY_H

#include <QtCore/QObject>

#include "abstractgroupableitem.h"
#include "groupmanager.h"
#include "taskgroup.h"
#include "taskmanager_export.h"

class QAction;

namespace TaskManager
{

/**
 * Base class for strategies which can be used to
 * automatically group tasks.
 */
class TASKMANAGER_EXPORT AbstractGroupingStrategy : public QObject
{
    Q_OBJECT
public:
    AbstractGroupingStrategy(GroupManager *groupManager);
    virtual ~AbstractGroupingStrategy();

    /**
     * Whether the grouping strategy will undo the current group topology
     * when it is destroyed.
     *
     * See also destroyGroups().
     */
    bool destroyGroupsOnDestruction() const;

    /**
     * Setting this to false prevents the grouping strategy from undoing
     * the current group toplogy when it is destroyed. This is mostly
     * useful to avoid unnecessary work during shutdown.
     *
     * See also destroyGroups().
     */
    void setDestroyGroupsOnDestruction(bool destroy);


    /** Handles a new item */
    virtual void handleItem(AbstractGroupableItem *) = 0;

    /** Returns the strategy type */
    GroupManager::TaskGroupingStrategy type() const;

    /** DesktopChanges time to backup any needed data */
    virtual void desktopChanged(int newDesktop);

    /**
    * Returns list of actions that a task can do in this groupingStrategy
    *  If the visualization supports grouping it has to show these actions.
    */
    virtual QList<QAction*> strategyActions(QObject *parent, AbstractGroupableItem *item);

    /** Returns the root group to use in grouping */
    GroupPtr rootGroup() const;

    enum EditableGroupProperties {
        None = 0,
        Name = 1,
        Icon =  4,
        Members = 8,
        All = 15
    };
    /**
    * Returns which group properties are editable by the user and which are handled solely by the strategy.
    * The visualization should create a configuration interface based on this.
    */
    virtual EditableGroupProperties editableGroupProperties() = 0;

    /* The following functions check if a property is editable and sets it on group*/

    virtual bool setName(const QString &, TaskGroup*);
    /** Returns a List of unused Names*/
    virtual QList<QString> nameSuggestions(TaskGroup *);

    virtual bool setIcon(const QIcon &, TaskGroup*);
    /** Returns a list of icons*/
    virtual QList<QIcon> iconSuggestions(TaskGroup *);

    /** Adds an item to group if EditableGroupProperties::Members is set */
    bool manualGroupingRequest(AbstractGroupableItem* taskItem, TaskGroup* groupItem);
    /**
    * Creates a new group if EditableGroupProperties::Members is set
    * Should be called if the user wants to group items manually
    */
    bool manualGroupingRequest(ItemList items);

protected:
    /** Create a group with items and returns the newly created group */
    TaskGroup* createGroup(ItemList items);

Q_SIGNALS:
    void groupRemoved(TaskGroup*);

protected Q_SLOTS:
    /** Uncollapse all groups into the root group. */
    void destroyGroups();

    /** Adds all group members to the parentgroup of group and removes the group */
    virtual void closeGroup(TaskGroup *group);

    /** Checks if the group is still necessary, removes group if empty*/
    virtual void checkGroup();

    /** Returns the strategy type */
    void setType(GroupManager::TaskGroupingStrategy type);

private:
    class Private;
    Private * const d;
};

} // TaskManager namespace
#endif