ASYNCHRONOUS - Java EE Design Patterns - page 116

async low

perform
asynchronous
work

make
data
available

perform
security
check

perform
asynchronous
work

request
some data

display
response

classic asynchronous request/response low

FIGURE 9-1: Asynchronous l ow diagram

IMPLEMENTING ASYNCHRONOUS PATTERN
IN PLAIN CODE

Java has supported threads that you can easily use for asynchronous code execution from its initial
design:
public class AsyncRunnable implements Runnable {

public void run() {
System.out.println("Running!");
}
}

To execute the Runnable class, initialize it in a thread and invoke the run method by calling the
start() method on the newly created thread:
(new Thread(new AsyncRunnable())).start();

Although the preceding example is the preferred way to start a thread process, another approach is
to extend the thread class and override the run() method:
public class AsyncThread extends Thread {

public void run() {
System.out.println("Running!");
}

}

To execute the class, instantiate it and then call the start() method:
(new HelloThread()).start();