Caucho Technology
  • hessian 3.1
  • hessian/burlap java binding draft spec


      Introduction

      Burlap and Hessian use type names in two contexts:

      • as <type> values for lists and objects.
      • as mangled names for method overloading

      The mapping from a language's types to the Burlap/Hessian names is necessarily language dependent, but designed for cross-language use.

      Java to Burlap/Hessian

      The mapping of specific Java types to Burlap/Hessian is relatively straightforward. A Java implementation will also use this mapping when it's parsing and knows the type of the object. Contrast that with the Burlap to Java mapping. Note that XML DOM is mapped to a string.

      JAVABURLAP
      nullnull
      Stringstring
      booleanboolean
      byteint
      shortint
      intint
      longlong
      floatdouble
      doubledouble
      charstring
      Booleanboolean
      Byteint
      Shortint
      Integerint
      Longlong
      Floatdouble
      Doubledouble
      Characterstring
      JAVABURLAP
      Stringstring
      StringBufferstring
      char[]string
      org.w3c.dom.Nodestring
      byte[]base64
      Object[][object
      JAVABURLAP
      Datedate
      Listlist
      Vectorlist
      Mapmap
      HashMapmap
      Hashtablemap
      Objectmap (with serialization)
      EJBHomeremote (using HomeHandle)
      EJBObjectremote (using Handle)
      Note Some of these conversions are lossy. For example, a Byte object serialized and then deserialized will become an Integer. This is the price paid working with other languages.

      Method overloading

      Java-based servers typically expose three overloaded methods:

      • The simple method name, which corresponds to the shorted overloaded method.
      • The method name with the number of arguments appended, e.g. add__2.
      • The method name with the Burlap/Hessian types, e.g. add_int_int

      In this case, all of "add" , "add__2", and "add_int_int" will map to the same method. The client will use whichever is appropriate to its capabilities. For example, many scripting languages can only handle the number of arguments as a mangling technique.

      Burlap to Java

      In several cases, a Java parser may know nothing about the expected type. For example, an method's argument might be Object or the serialized data may be in a Vector, or a client may not specify the type for a <map>.

      BURLAPJAVA
      nullnull
      booleanBoolean
      intInteger
      doubleDouble
      stringString
      dateDate
      base64byte []
      listArrayList
      mapHashMap

      Changes

      v3 changes (2001-12-27)

      • Change ;ejbid= to ?ejbid=

      v2 changes

      • Change SML-RPC to Burlap

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