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In the left side of Eclipse, that is the package explorer.
Use mouse to expend cs.ecl.basics.simple, I can see src and JRE System Library.
4. Editing Java element I clicked Library.java and added following code: @Override public String toString() { return "Library [resources=" + resources + "]"; } 5. Creating a Java class
In package explorer, right click on src folder, and select new->class,
type student, and click enter key.
Actually Library.java is a class, I'm going to use it as an example
instead of student.java.
6. Renaming Java elements
I changed Video.java to Audio.java by changing the interface name.
7. Moving and copying Java elements
I copied Audio.java and paste it in the project, and changed name to Video, then Video.java is created.
If I use mouse to move Video.java to Media.java, it's the same as copying.
8. Navigate to a Java element's declaration
In Library.java, I hightlight Media, the Media became gray background.
Then I right click on Media, and select open declearation, it switch to
Media.java.
9. Viewing the type Hierarchy
In Media.java, I hightlight Media, the Media became gray background.
Then I right click on Media, and select open type hierarchy.
The left panel show Media as a menu, Audio, Book, Video as sub menu.
10.Searching the workbench
In menu, select search, a window pop up.
I input Audio, and click search.
At the bottom of eclipse, a window shows 1 match in workspace.
And it showed public interface Audio extends Media{
I click on that, it switched to Audio.java.
11.Running your programs
I changed the main in Library.java:
public static void main(String[] args) {
System.out.println("Hello");
Audio a = null;
Library<Audio> La = new Library<Audio>();
La.addMedia(a);
System.out.println(La.retrieveLast());
}
I clicked run, it shows:
Hello
null
12.Debugging your programs
In Main procedure, I click the line La.addMedia(a), a blue dot appear
on the left La.addMedia(a). In menu, I click run->debug. when popup a window,
click yes. Then the program will stop at La.addMedia(a).
I can choose run->step into in the menu to follow the program.
I can click run->terminate to end the debugging.
13.Evaluating expressions
In menu, I select window->show view->expressions.
I added La, Audio and 3+3.
Then I click debug.
The program stopped at La.AddMedia(a);
In expressions window, it shows:
"La" (id=16)
"Audio" <error(s)_during_the_evaluatior
6
So expressions can be used in debug mode to check the runtime value.
14.Evaluating snippets
snippets used to speed up typing.
for example: I put Audio.java as a snippet, named InterfaceTemplate,
and add a variable name_1, default value is "Audio".
package cs.ecl.basics.simple.example1;
public interface ${name_1} extends Media {
}
I created a DVD.java interface, open it, and I deleted everything in
DVD.java. Then I drag it to the middle empty place, it popped a window.
I changed the value of name_1 to DVD. Then DVD.java is created.
15.Using the Java browsing perspective
In menu, select Window->Open perspective->Java browsing.
A new windows arrangement shows:
The top 4 windows are projects, packages, types and members.
The bottom window is the program window.
I can drag what I want from types and members to the bottom window.
It's very convenience for programming.
16.Writing and running JUnit tests
Since the package cs.ecl.basics.simple is already include test folder.
Also it includes testAddMedia() and testRetrieveLast() functions.
I clicked run, it shows 2 errors:
@Test
public void testAddMedia() {
fail("Not yet implemented");
}
@Test
public void testRetrieveLast() {
fail("Not yet implemented");
}
I changed to following:
package cs.ecl.basics.simple.example1;
import junit.framework.Assert;
import org.junit.Test;
public class LibraryTest {
Library<DVD> Ld = new Library<DVD>();
@Test
public void testAddMedia() {
DVD d = null;
Ld.addMedia(d);
}
@Test
public void testRetrieveLast() {
Assert.assertEquals(null,Ld.retrieveLast());
}
}
The program runs correctly.
Assert.asserEquals is a function to check 2 parameters are equal or not.
End.
