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See the License for the 17 * specific language governing permissions and limitations 18 * under the License. 19 * 20 *************************************************************/ 21 22 23#ifndef __com_sun_star_uno_XInterface_idl__ 24#define __com_sun_star_uno_XInterface_idl__ 25 26//============================================================================= 27 28 module com { module sun { module star { module uno { 29 30//============================================================================= 31 32// DocMerge from xml: interface com::sun::star::uno::XInterface 33/** base interface of all UNO interfaces 34 35 <p> It provides lifetime control by reference counting and the 36 possibility of querying for other 37 interfaces of the same logical object. 38 39 40 <p> 41 "Logical Object" in this case means that the 42 interfaces actually can be supported by internal (e.g. aggregated) physical objects.</p> 43 44 <p> Deriving from this interface is mandatory for all UNO interfaces. 45 <p> Each language binding (Java, C++, StarBasic, Python, ... ) may 46 provide a different mapping of this interface, please look into the language 47 dependent documentation. 48 49 <p> The UNO object does not export the state of the reference count (acquire() and 50 release() do not have return values). In general, also the UNO object itself 51 should not make any assumption on the concrete value of the reference count 52 (except on the transition from one to zero ). 53 54 */ 55published interface XInterface 56{ 57 /** queries for a new interface to an existing UNO object. 58 <p> 59 The queryInterface() method is the entry point to obtain other interfaces which 60 are exported by the object. The caller asks the implementation of the object, 61 if it supports the interface specified by the type argument. The call may either 62 return with a interface reference of the requested type or with a void any. 63 64 <p> 65 There are certain specifications, a queryInterface() implementation must not violate. 66 <p> 67 1) If queryInterface on a specific object has once returned a valid interface reference 68 for a given type, it must return a valid reference for any successive queryInterface 69 calls on this object for the same type. 70 <p> 71 2) If queryInterface on a specific object has once returned a null reference 72 for a given type, it must always return a null reference for the same type. 73 <p> 74 3) If queryInterface on a reference A returns reference B, queryInterface on 75 B for Type A must return interface reference A or calls made on the returned 76 reference must be equivalent to calls made on reference A. 77 <p> 78 4) If queryInterface on a reference A returns reference B, queryInterface on 79 A and B for XInterface must return the same interface reference (object identity). 80 81 <p> The reason for the strong specification is, that a Uno Runtime Environment (URE) 82 may choose to cache queryInterface() calls. 83 <p> As mentioned above, certain language bindings may map this function differently also 84 with different specifications, please visit the language dependent specification for it. 85 The current C++ binding sticks to the specification state 86 <p> 87 The rules mentioned above are basically identical to the rules of QueryInterface in MS COM. 88 89 @param aType a UNO interface type, for which an object reference shall be obtained. 90 @return an interface reference in case the requested interface is supported by the object, 91 a void any otherwise. 92 */ 93 any queryInterface( [in] type aType ); 94 95 //------------------------------------------------------------------------- 96 /** increases the reference counter by one. 97 98 <p>When you have called acquire() on the 99 UNO object, it is often said, that you have a reference or a hard reference 100 to the object. 101 102 <p> 103 It is only allowed to invoke a method on an UNO object, when you keep 104 a hard reference to it. 105 106 <p> Every call to acquire must be followed by a corresponding call to release 107 some time later, which may eventually lead to the destruction of the object. 108 */ 109 [oneway] void acquire(); 110 111 //------------------------------------------------------------------------- 112 113 // DocMerge from xml: method com::sun::star::uno::XInterface::release 114 /** decreases the reference counter by one. 115 <p>When the reference counter reaches 0, the object gets deleted.</p> 116 <p>Calling release() on the object is often called releasing 117 or clearing the reference to an object. 118 */ 119 [oneway] void release(); 120 121}; 122 123//============================================================================= 124 125}; }; }; }; 126 127/*============================================================================= 128 129=============================================================================*/ 130#endif 131