1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
// This example illustrates the manipulation of C++ references in Java.
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[])
{
System.out.println( "Creating some objects:" );
Vector a = new Vector(3,4,5);
Vector b = new Vector(10,11,12);
System.out.println( " Created " + a.print() );
System.out.println( " Created " + b.print() );
// ----- Call an overloaded operator -----
// This calls the wrapper we placed around
//
// operator+(const Vector &a, const Vector &)
//
// It returns a new allocated object.
System.out.println( "Adding a+b" );
Vector c = example.addv(a,b);
System.out.println( " a+b = " + c.print() );
// Note: Unless we free the result, a memory leak will occur if the -noproxy commandline
// is used as the proxy classes define finalizers which call the delete() method. When
// -noproxy is not specified the memory management is controlled by the garbage collector.
// You can still call delete(). It will free the c++ memory immediately, but not the
// Java memory! You then must be careful not to call any member functions as it will
// use a NULL c pointer on the underlying c++ object. We set the Java object to null
// which will then throw a Java exception should we attempt to use it again.
c.delete();
c = null;
// ----- Create a vector array -----
System.out.println( "Creating an array of vectors" );
VectorArray va = new VectorArray(10);
System.out.println( " va = " + va.toString() );
// ----- Set some values in the array -----
// These operators copy the value of Vector a and Vector b to the vector array
va.set(0,a);
va.set(1,b);
// This works, but it would cause a memory leak if -noproxy was used!
va.set(2,example.addv(a,b));
// Get some values from the array
System.out.println( "Getting some array values" );
for (int i=0; i<5; i++)
System.out.println( " va(" + i + ") = " + va.get(i).print() );
// Watch under resource meter to check on this
System.out.println( "Making sure we don't leak memory." );
for (int i=0; i<1000000; i++)
c = va.get(i%10);
// ----- Clean up -----
// This could be omitted. The garbage collector would then clean up for us.
System.out.println( "Cleaning up" );
va.delete();
a.delete();
b.delete();
}
}
|
