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The IComponentLoader class loads a plugin at run-time. More...
#include <IComponentLoader.h>
Inherited by ComponentLoader.
Public Member Functions | |
| virtual | ~IComponentLoader () |
| virtual bool | deleteInstance ()=0 |
| virtual QString | errorString () const =0 |
| virtual QString | fileName () const =0 |
| virtual IComponent * | instance ()=0 |
| virtual bool | isLoaded () const =0 |
| virtual bool | load ()=0 |
| virtual QLibrary::LoadHints | loadHints () const =0 |
| virtual void | setFileName (const QString &fileName)=0 |
| virtual void | setLoadHints (QLibrary::LoadHints loadHints)=0 |
| virtual bool | unload ()=0 |
The IComponentLoader class loads a plugin at run-time.
It is very similiar with QPluginLoader, but with few differences: IComponentLoader returns IComponent instead of QObject; IComponentLoader can be used with if your application is statically linked against Qt; IComponentLoader takes ownership for the loaded component instance; Load hints are set to QLibrary::ResolveAllSymbolsHint and QLibrary::ExportExternalSymbolsHinthints by default to enable RTTI cross the library bounds (used in IServiceLocator).
IComponentLoader provides access to a IComponent, stored in a shared library (a DLL) and offers these benefits over shared libraries accessed using QLibrary.
IComponentLoader provides direct access to a component object (instance()), instead of forcing you to resolve a C function manually.
An instance of a IComponentLoader object operates on a single shared library file, which we call a component. It provides access to the functionality in the component in a platform-independent way. To specify which component to load, either pass a file name in the constructor or set it with setFileName().
The most important functions are load() to dynamically load the component file, isLoaded() to check whether loading was successful, and instance() to access the root in the component. The instance() function implicitly tries to load the component if it has not been loaded yet.
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inlinevirtual |
Destroys the IComponentLoader object.
unload() will be called explicitly, the component will be destroyed (if any).
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pure virtual |
Returns a text string with the description of the last error that occurred.
Implemented in ComponentLoader.
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pure virtual |
Deletes the component and returns true if the component was deleted; otherwise returns false.
This happens automatically on ComponentLoader destructor, so you shouldn't normally need to call this function.
If other instances of ComponentLoader are using the same component, the call will fail, and unloading will only happen when every instance has called unload().
Don't try to delete the component object. Instead rely on that deleteInstance() will automatically delete it.
Implemented in ComponentLoader.
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pure virtual |
Returns the file name of the component.
By default, this property contains an empty string.
Implemented in ComponentLoader.
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pure virtual |
Returns the root object of the component. The component is loaded if necessary. The function returns nullptr if the component could not be loaded or if the component could not be instantiated.
If the component object was destroyed (unload()), calling this function creates a new instance.
The root component, returned by this function, is deleted when the IComponentLoader is destroyed. If you want to manage component lifetime your-self, you should call unload().
Implemented in ComponentLoader.
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pure virtual |
Returns true if the component is loaded; otherwise returns false.
Implemented in ComponentLoader.
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pure virtual |
Loads the component and returns true if the component was loaded successfully; otherwise returns false. Since instance() always calls this function before resolving any symbols it is not necessary to call it explicitly. In some situations you might want the component loaded in advance, in which case you would use this function.
Implemented in ComponentLoader.
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pure virtual |
Gets the give the load() function some hints on how it should behave. By default, QLibrary::ResolveAllSymbolsHint and QLibrary::ExportExternalSymbolsHinthints are set to enable RTTI cross the library bounds.
See the documentation of QLibrary::loadHints() for a complete description of how this property works.
Implemented in ComponentLoader.
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pure virtual |
Sets the file name of loaded component library.
To be loadable, the file's suffix must be a valid suffix for a loadable library in accordance with the platform, e.g. .so on Unix, .dylib on Mac OS X, and .dll on Windows. The suffix can be verified with QLibrary::isLibrary().
If the file name does not exist, it will not be set. This property will then contain an empty string.
Implemented in ComponentLoader.
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pure virtual |
Sets the file name of loaded component library.
Implemented in ComponentLoader.
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pure virtual |
Unloads the component and returns true if the component could be unloaded; otherwise returns false.
This happens automatically on IComponentLoader destructor, so you shouldn't normally need to call this function.
If other instances of IComponentLoader are using the same component, the call will fail, and unloading will only happen when every instance has called unload().
Don't try to delete the component object. Instead rely on that unload() will automatically delete it when needed.
Implemented in ComponentLoader.
1.8.5
