Software Development Cross Solution - Index of - Free

merging changes
Most version control tools will try
and solve problems for you
Suppose you had a version control system in place before the great BeatBox debacle
of ’08. You’d check in your code (with commit) to implement Send Poke, and then
Bob would change his code, and try to commit his work on Send Picture:
Bob tries to check in his code...
public class RemoteReader implements Runnable {
boolean[] checkboxState = null;
String nameToShow = null;
Object obj = null;
public void run() {
try {
while ((obj = in.readObject()) != null) {
System.out.println("got an object from server");
System.out.println(obj.getClass());
String nameToShow = (String) obj;
checkboxState = (boolean[]) in.readObject();
if (nameToShow.equals(PICTURE_START_SEQUENCE)) {
receiveJPEG();
}
else {
otherSeqsMap.put(nameToShow, checkboxState);
listVector.add(nameToShow);
incomingList.setListData(listVector);
// now reset the sequence to be this
}
} // close while
} catch (Exception ex) {
ex.printStackTrace();
}
} // close run
} // close inner class
192 Chapter 6
public class RemoteReader implements Runnable {
boolean[] checkboxState = null;
String nameToShow = null;
Object obj = null;
public void run() {
try {
while ((obj = in.readObject()) != null) {
System.out.println("got an object
from server");
System.out.println(obj.getClass());
String nameToShow = (String) obj;
checkboxState = (boolean[]) in.readObject();
if (nameToShow.equals(PICTURE_START_
SEQUENCE)) {
receiveJPEG();
}
else {
otherSeqsMap.put(nameToShow, checkboxState);
listVector.add(nameToShow);
incomingList.setListData(listVector);
// now reset the sequence to be this
}
} // close while
} catch (Exception ex) {
ex.printStackTrace();
}
} // close run
Bob’s picture sending
implementation
...but quickly runs into a problem.
Bob’s code
svn commit -m "Added pictures."
You and Bob both made changes
to the same file; you just got
yours into the repository first.
// ... the code below is from BeatBoxFinal.java buildGUI() ...
JButton sendIt = new JButton("sendIt");
sendIt.addActionListener(new MySendListener());
buttonBox.add(sendIt);
JButton sendPoke = new JButton("Send Poke");
sendPoke.addActionListener(new MyPokeListener());
buttonBox.add(sendPoke);
userMessage = new JTextField();
buttonBox.add(userMessage);
// ... this is new code we need to add to BeatBoxFinal.java ...
public class MyPokeListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
//
We'll create an empty state array here
boolean[] checkboxState = new boolean[256];
try
{
out.writeObject(POKE_SEQUENCE);
out.writeObject(checkboxState);
}
catch (Exception ex) { System.out.println("Failed to poke!"); }
}
}
public class RemoteReader implements Runnable {
boolean[] checkboxState = null;
String nameToShow = null;
Object obj = null;
public void run() {
try {
while((obj=in.readObject()) != null) {
System.out.println("got an object from server");
System.out.println(obj.getClass());
String nameToShow = (String) obj;
checkboxState = (boolean[]) in.readObject();
if (nameToShow.equals(POKE_START_SEQUENCE)) {
playPoke();
nameToShow = "Hey! Pay attention.";
}
otherSeqsMap.put(nameToShow, checkboxState);
listVector.add(nameToShow);
incomingList.setListData(listVector);
} // close while
} catch(Exception ex) {ex.printStackTrace();}
} // close run
private void playPoke() {
Toolkit.getDefaultToolkit().beep();
}
} // close inner class
Here’s your code—safe and
sound in the repository.
The code on the server,
with your changes
Bob’s BeatBox.java BeatBox.java
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