Java

Implementing AST Vistitor inside or outside the Analysis class

29-Jan-12 5:38

I have suggested how to use sockets and given some links to information on RPC; writing the actual code is your part of the deal.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Re: Urgent help me

Pinguin201128-Jan-12 22:48

Pinguin2011

28-Jan-12 22:48

no help

Re: Urgent help me

jschell30-Jan-12 8:58

jschell

30-Jan-12 8:58

Pinguin2011 wrote:
I'm really blocked I do not know how to start my application.

1. Learn basics of java
2. Learn basics of programming java on Android
3. Learn basics of implementing a java server with a web interface.
4. Learn how to write an Android app that can talk to a server
5. Learn basics of C
6. Learn how to make C and Java talk to each other (I suggest using application via Runtime rather than JNI.)
7. Collect requirements for your Android App and Server
8. Design a system (more than one application) using all you have learned and based on 7.
9. Implement the design.
10. Unit test the design.

Wathsala Bandara28-Jan-12 5:07

Wathsala Bandara

28-Jan-12 5:07

Hi,
I'm writing a simple visitor-based analysis in Java using Eclipse. Here I have to implement a tree-walker analysis within Crystal. But I wanna know the difference (advantages/disadvantages) between implementing the visitor class inside the analysis class or outside that.

Ex: Inner visitor class
public class MyAnalysis extends AbstractCrystalMethodAnalysis {
...
private class MyVisitor extends ASTVisitor {
...
}
...
}

I really appreciate if some can tell me the difference between these two implementations.

Re: Implementing AST Vistitor inside or outside the Analysis class

David Skelly29-Jan-12 22:19

David Skelly

29-Jan-12 22:19

I would turn the question around and ask: why do you want to make the visitor a private inner class? What are you hoping to gain by doing that?

Re: Implementing AST Vistitor inside or outside the Analysis class

Wathsala Bandara30-Jan-12 5:23

Wathsala Bandara

30-Jan-12 5:23

I'm new to this stuff. I was following some sample codes and there I saw inner-class implementations. So I wonder what's the difference between inner and outter implementations. BTW I'm implementing the AST visitor as a public class even inside the Analysis class.

Re: Implementing AST Vistitor inside or outside the Analysis class

David Skelly30-Jan-12 6:31

David Skelly

30-Jan-12 6:31

Usage of inner classes is one of those things that some Java coders get very worked up about, for and against. Personally, I don't much like them but they have their uses.

There are plenty of opinions on the net about whether to use them, when to use them, how to use them. For every one person who says "Do it this way" you will find another who says "Don't do it that way".

The one thing I would say is: if you are making AST Visitor publicly visible outside Analysis, why not just make it an outer class on its own? What do you gain by making it an inner class of Analysis?

How can I run an .exe file in a program in java?

Member 845978328-Jan-12 4:14

Member 8459783

28-Jan-12 4:14

I want to run an exe file in my project.
I mean when I run my codes,a specific executable file run.
How can I do that?

Re: How can I run an .exe file in a program in java?

Richard MacCutchan28-Jan-12 5:01

Re: How can I run an .exe file in a program in java?

28-Jan-12 5:01

I expect you want to use the Runtime[^] class.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

David Skelly29-Jan-12 22:15

David Skelly

29-Jan-12 22:15

Since 1.5 ProcessBuilder has been recommended over Runtime. Having said that, I still use Runtime because it's what I'm used to and old habits die hard.

Re: How can I run an .exe file in a program in java?

Richard MacCutchan29-Jan-12 23:51

Re: Layout Managers in java

29-Jan-12 23:51

I used Google to check; it's a while since I sat and read the latest documentation and guidance notes.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Layout Managers in java

Sandeep9040928-Jan-12 3:00

Sandeep90409

28-Jan-12 3:00

tell me about Layout Managers
i want to use it in my applet programes Confused | :confused:

Richard MacCutchan28-Jan-12 4:56

problem with arrays in java

28-Jan-12 4:56

I have already made a suggestion here[^]. Please do not repeat the same question in multiple forums.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Member 858607227-Jan-12 20:56

27-Jan-12 20:56

hi...I'm writing a program for converting nfa to dfa...for getting alphabet and rules(which are array) and other elements in nfa (which are not arrays) I've defined a "NFA" class and for converting another class "NfaToDfa"...when I create an object from "NFA" class and I want to use for example "getrules" method in "NfaToDfa" there's an error...notice that for the other elements which are integer or...(anything except array) there's no error...what can I do ?

Java

   NFA NFATo=new NFA();
  String[ ][ ] Rules=new String[100][3];
  Rules=NFATo.getRule();
 String[] alphabet=new String[27];
alphabet=NFATo.getAlpha();

I have error in line 3 and 5...the error is "cannot find symbol"...can anyone help me with this problem ?

Richard MacCutchan27-Jan-12 22:40

27-Jan-12 22:40

What symbol can the compiler not find, i.e. post the full text of the error message.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Member 858607227-Jan-12 22:54

27-Jan-12 22:54

the error is :

XML

cannot find symbol
  symbol:   class Rules
  location: class nfa2dfa.NfaToDfa

<identifier> expected

cannot find symbol
  symbol:   method getRule()
  location: class nfa2dfa.NFA

Member 858607227-Jan-12 22:57

27-Jan-12 22:57

and the same error for "getAlpha"...

Richard MacCutchan27-Jan-12 23:30

27-Jan-12 23:30

Well that seems quite clear, the run time system cannot find method getRule().

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Member 858607228-Jan-12 1:12

28-Jan-12 1:12

well...I know what the problem is but I don't know how to solve it ! because I've already defined "getRules" method in NFA class...and there's no error in that method...

Richard MacCutchan28-Jan-12 1:28

28-Jan-12 1:28

Then I can only assume that you are running a different version of your program, or some class is not in the correct place. Given the information you have provided here I cannot begin to guess what the structure of your classes is or how you are running the program. I would suggest you use your debugger to try and find out what is happening.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Richard MacCutchan28-Jan-12 1:37

28-Jan-12 1:37

I just copied the 5 lines of code in your original message into a Java program, added implementations for the constructor and two methods and it works fine. What are you doing that is different?

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Richard MacCutchan28-Jan-12 2:30

28-Jan-12 2:30

OK, I've figured out what the problem may be. If you are manually compiling the class that uses NFA then you need to be in the correct directory for the compiler to find the class. If these classes are in a package then you need to start from the directory above the package directory. For example if class NFA is in directory test, and NFA is part of package test then you need to compile from the next higher directory as follows:

C:\Documents\Java\testing>dir test
 Volume in drive C is System
 Volume Serial Number is F28F-2710

 Directory of C:\Documents\Java\testing\test

28/01/2012  13:20    <DIR>          .
28/01/2012  13:20    <DIR>          ..
28/01/2012  12:44             1,000 MyTest.java
28/01/2012  12:44             1,598 NFA.class
28/01/2012  12:44               917 NFA.java
               2 File(s)        3,515 bytes
               2 Dir(s)  177,110,560,768 bytes free

C:\Users\Richard\Documents\Java\testing>
javac -cp . test/MyTest.java

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

jschell28-Jan-12 4:45

jschell

28-Jan-12 4:45

Member 8586072 wrote:
but I don't know how to solve it ! because I've already defined "getRules"

Presumably that is just a problem in your post rather than in what you implemented because that is not the method that is missing.

Richard MacCutchan28-Jan-12 4:54