As we discussed in Understanding the role of JNI, C++ is designed for manual memory management. It frees memory on command, not on a garbage collector's schedule. If we want to provide a degree of manual memory management to Java users as well, we can write a public method that is responsible for freeing any C++ resources (or other unmanaged resources) associated with a Java class. Conventionally, such a method is named dispose. Since several of our Filter implementations will own C++ resources, let's add a dispose method to Filter.java:
public interface Filter {
public abstract void dispose();
public abstract void apply(final Mat src, final Mat dst);
}Let's modify NoneFilter.java to provide an empty implementation of dispose, as seen in the following code:
public class NoneFilter implements Filter {
@Override
public void dispose() {
// Do nothing.
}
@Override
public void apply(final Mat src, final Mat dst) {
// Do nothing.
}
}Similarly...