/tags/rel-2.0.2/Examples/java/extend/runme.java
# · Java · 88 lines · 41 code · 19 blank · 28 comment · 0 complexity · d07115e05c365bd6c943e4513aad973e MD5 · raw file
- // This file illustrates the cross language polymorphism using directors.
- // CEO class, which overrides Employee::getPosition().
- class CEO extends Manager {
- public CEO(String name) {
- super(name);
- }
- public String getPosition() {
- return "CEO";
- }
- // Public method to stop the SWIG proxy base class from thinking it owns the underlying C++ memory.
- public void disownMemory() {
- swigCMemOwn = false;
- }
- }
- public class runme {
- static {
- try {
- System.loadLibrary("example");
- } catch (UnsatisfiedLinkError e) {
- System.err.println("Native code library failed to load. See the chapter on Dynamic Linking Problems in the SWIG Java documentation for help.\n" + e);
- System.exit(1);
- }
- }
- public static void main(String argv[])
- {
- // Create an instance of CEO, a class derived from the Java proxy of the
- // underlying C++ class. The calls to getName() and getPosition() are standard,
- // the call to getTitle() uses the director wrappers to call CEO.getPosition().
- CEO e = new CEO("Alice");
- System.out.println( e.getName() + " is a " + e.getPosition() );
- System.out.println( "Just call her \"" + e.getTitle() + "\"" );
- System.out.println( "----------------------" );
- // Create a new EmployeeList instance. This class does not have a C++
- // director wrapper, but can be used freely with other classes that do.
- EmployeeList list = new EmployeeList();
- // EmployeeList owns its items, so we must surrender ownership of objects we add.
- e.disownMemory();
- list.addEmployee(e);
- System.out.println( "----------------------" );
- // Now we access the first four items in list (three are C++ objects that
- // EmployeeList's constructor adds, the last is our CEO). The virtual
- // methods of all these instances are treated the same. For items 0, 1, and
- // 2, all methods resolve in C++. For item 3, our CEO, getTitle calls
- // getPosition which resolves in Java. The call to getPosition is
- // slightly different, however, because of the overidden getPosition() call, since
- // now the object reference has been "laundered" by passing through
- // EmployeeList as an Employee*. Previously, Java resolved the call
- // immediately in CEO, but now Java thinks the object is an instance of
- // class Employee. So the call passes through the
- // Employee proxy class and on to the C wrappers and C++ director,
- // eventually ending up back at the Java CEO implementation of getPosition().
- // The call to getTitle() for item 3 runs the C++ Employee::getTitle()
- // method, which in turn calls getPosition(). This virtual method call
- // passes down through the C++ director class to the Java implementation
- // in CEO. All this routing takes place transparently.
- System.out.println( "(position, title) for items 0-3:" );
- System.out.println( " " + list.get_item(0).getPosition() + ", \"" + list.get_item(0).getTitle() + "\"" );
- System.out.println( " " + list.get_item(1).getPosition() + ", \"" + list.get_item(1).getTitle() + "\"" );
- System.out.println( " " + list.get_item(2).getPosition() + ", \"" + list.get_item(2).getTitle() + "\"" );
- System.out.println( " " + list.get_item(3).getPosition() + ", \"" + list.get_item(3).getTitle() + "\"" );
- System.out.println( "----------------------" );
- // Time to delete the EmployeeList, which will delete all the Employee*
- // items it contains. The last item is our CEO, which gets destroyed as well.
- list.delete();
- System.out.println( "----------------------" );
- // All done.
- System.out.println( "java exit" );
- }
- }