Overview

The GigaSpaces C++ interface is based on a C++ projection of the JavaSpaces API. C++ applications can access the space directly using the projected versions of the regular JavaSpaces methods. Objects must be wrapped using the C++ projection of the ExternalEntry class (com::j_spaces::core::client::ExternalEntry; see C++ API Documentation). The C++ package is located at <GigaSpaces Root>/CPP.

Working with Projected Classes

Please note the following when working with GigaSpaces classes projected to C++:

• Package names – in the package filenames of Java classes projected to C++, periods change into underscores. For example, the Java package name com.j_spaces.core.client.java becomes com_j_spaces_core_client_pkg.h when you project it into C++.
• Namespaces – use normal C++ namespaces when referring to a projected class in the code. For example, to refer to the class SpaceFinder, enter com::j_spaces::core::client::SpaceFinder.
• Objects returned by projected classes – C++ methods that are projections of static Java methods always return a generic Java object, regardless of the type of object stated in the header. To cast the object back into the original type, call the dyna_cast method from within the class the object belongs to (all projected C++ classes provide this method). Pass the object as an argument. The method returns the object cast into its original type.

Importing C++ Classes into GigaSpaces

According to the JavaSpaces specification, only Entries can be written to and read from a space. To write C++ objects to a space, you must use the ExternalEntry wrapper, which stores the meta data of a class in a JavaSpaces-compatible format. You can then write this wrapper to the space (see Using ExternalEntry for more details).

You must use the C++ projection of the ExternalEntry class (com::j_spaces::core::client::ExternalEntry; see C++ API Documentation). A JavaSpaces-compatible wrapper is returned to you transparently. You can then call the C++ projection of the Write() method, passing xe (external entry) and the wrapped object as arguments.

Section Contents

• CPP Examples — Finding a space; writing to and reading from space; working with transactions; using notifications; working with exceptions.
• Java-to-CPP Mapping of Arrays — Array types; features; user restriction; multi-dimensional arrays; block accessors.
• Java-to-CPP Mapping of Strings — Creating and using a Java String instance; extracting native characters; using strings in printf calls; mixing MFC CString and Java String instances.
• Monitoring JVM Memory and Threads in CPP Applications — Monitoring JVM memory and threads in C++ Applications, when troubleshooting application memory and thread consumption.