udkapi/com/sun/star/uno/XInterface.idl

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  30 #ifndef __com_sun_star_uno_XInterface_idl__
  31 #define __com_sun_star_uno_XInterface_idl__
  32
  33 //=============================================================================
  34
  35  module com {  module sun {  module star {  module uno {
  36
  37 //=============================================================================
  38
  39 // DocMerge from xml: interface com::sun::star::uno::XInterface
  40 /** base interface of all UNO interfaces
  41
  42     <p> It provides lifetime control by reference counting and the
  43     possibility of querying for other
  44     interfaces of the same logical object.
  45
  46
  47     <p>
  48     "Logical Object" in this case means that the
  49     interfaces actually can be supported by internal (e.g. aggregated) physical objects.</p>
  50
  51     <p> Deriving from this interface is mandatory for all UNO interfaces.
  52     <p> Each language binding (Java, C++, StarBasic, Python, ... ) may
  53     provide a different mapping of this interface, please look into the language
  54     dependent documention.
  55
  56     <p> The UNO object does not export the state of the reference count (acquire() and
  57         release() do not have return values). In general, also the UNO object itself
  58         should not make any assumption on the concrete value of the reference count
  59         (except on the transition from one to zero ).
  60
  61  */
  62 published interface XInterface
  63 {
  64     /** queries for a new interface to an existing UNO object.
  65         <p>
  66         The queryInterface() method is the entry point to obtain other interfaces which
  67         are exported by the object. The caller asks the implementation of the object,
  68         if it supports the interface specified by the type argument. The call may either
  69         return with a interface reference of the requested type or with a void any.
  70
  71         <p>
  72         There are certain specifications, a queryInterface() implementation must not violate.
  73         <p>
  74         1) If queryInterface on a specific object has once returned a valid interface reference
  75           for a given type, it must return a valid reference for any successive queryInterface
  76           calls on this object for the same type.
  77         <p>
  78         2) If queryInterface on a specific object has once returned a null reference
  79         for a given type, it must always return a null reference for the same type.
  80         <p>
  81         3) If queryInterface on a reference A returns reference B, queryInterface on
  82         B for Type A must return interface reference A or calls made on the returned
  83         reference must be equivalent to calls made on reference A.
  84         <p>
  85         4) If queryInterface on a reference A returns reference B, queryInterface on
  86         A and B for XInterface must return the same interface reference (object identity).
  87
  88         <p> The reason for the strong specification is, that a Uno Runtime Environment (URE)
  89         may choose to cache queryInterface() calls.
  90         <p> As mentioned above, certain language bindings may map this function differently also
  91         with different specifications, please visit the language dependent specification for it.
  92         The current C++ binding sticks to the specification state
  93         <p>
  94         The rules mentioned above are basically identical to the rules of QueryInterface in MS COM.
  95
  96         @param aType a UNO interface type, for which an object reference shall be obtained.
  97         @return an interface reference in case the requested interface is supported by the object,
  98                 a void any otherwise.
  99      */
 100     any queryInterface( [in] type aType );
 101
 102     //-------------------------------------------------------------------------
 103     /** increases the reference counter by one.
 104
 105         <p>When you have called acquire() on the
 106         UNO object, it is often said, that you have a reference or a hard reference
 107         to the object.
 108
 109         <p>
 110         It is only allowed to invoke a method on an UNO object, when you keep
 111         a hard reference to it.
 112
 113         <p> Every call to acquire must be followed by a corresponding call to release
 114         some time later, which may eventually lead to the destruction of the object.
 115      */
 116     [oneway] void acquire();
 117
 118     //-------------------------------------------------------------------------
 119
 120     // DocMerge from xml: method com::sun::star::uno::XInterface::release
 121     /** decreases the reference counter by one.
 122         <p>When the reference counter reaches 0, the object gets deleted.</p>
 123         <p>Calling release() on the object is often called releasing
 124         or clearing the reference to an object.
 125      */
 126     [oneway] void release();
 127
 128 };
 129
 130 //=============================================================================
 131
 132 }; }; }; };
 133
 134 /*=============================================================================
 135
 136 =============================================================================*/
 137 #endif