gomp-20050608-branch/libjava/classpath/org/omg/DynamicAny/package.html

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  39 <html>
  40 <head><title>GNU Classpath - org.omg.DynamicAny</title></head>
  41
  42 <body>
  43 <p>DynAny's allow to work with data structures, exact content of those is not
  44 known at the time of compilation. In this way, the conception of DynAny
  45 remebers the java reflection mechanism. DynAny usually obtain the value from
  46 the {@link org.omg.CORBA.Any} that, if needed, can carry highly nested data
  47 structures (like array of sequences of unions). DynAny's allow to see/modify
  48 all parts of such structures. This is especially helpful for writing generic
  49 servers (bridges, event channels supporting, filtering and so on). Similarly,
  50 DynAny's can create an Any at runtime, without having static knowledge of its
  51 type. This is helpful for writing generic clients like browsers, debuggers or
  52  user interface tools.
  53 </p><p>
  54 The API clearly states that DynAny and DynAnyFactory objects are local and
  55 cannot be transferred to remote server or client. While such methods are
  56 formally defined in the corresponding helpers, they simply always throw MARSHAL.
  57 </p><p>
  58 DynAny's are created by {@link DynAnyFactory}. The factory is obtaines by
  59 {@link org.omg.CORBA.ORB#resolve_initial_references):
  60 <code>
  61 ORB orb = ORB.init(new String[0], null);
  62 DynAnyFactory f = DynAnyFactoryHelper.narrow(orb.resolve_initial_references("DynAnyFactory"));
  63 </code>
  64 DynAny's are also returned by some methods, invoked on another DynAny.
  65 </p><p>
  66 The primitive types like string or char are wrapped into an ordinary DynAny. It
  67 has multiple methods for setting/getting the content like
  68 {@link DynAnyOperations#get_string()} or
  69 {@link DynAnyOperations#insert_string(String)}. The more complex types like
  70 sequences or structures are wrapped into specialised DynAny's, providing means
  71 to access the enclosed members. In this case, the DynAny has the
  72 "internal cursor", normally pointing at one of the members in the data
  73 structure. The "internal cursor" can be set to the needed position
  74 {@link DynAnyOperations#seek(int)} or advanced forward
  75 ({@link DynAnyOperations#next()}. The member under cursor is returned by
  76 {@link DynAnyOperations#current_component()}. For composite DynAnys the
  77 methods like {@link DynAnyOperations#get_string()} or
  78 {@link DynAnyOperations#insert_string(String)} apply to the selected member,
  79 not to the complex DynAny in general.
  80 </p><p>
  81 DynAnys are created and optimized for traversing values extracted from anys
  82 or constructing values of anys at runtime. OMG does not recommend to use them
  83 for other purposes.
  84 </p><p>
  85 @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
  86 </body>
  87 </html>