Stringes and interface Comparable

Hello
I was wondering if you would have a 'good' solution at the following problem.
Lets make it easy. I have a class named Farm. This farm has animals. Each of them have there own name and they have certain other characteristics. So there is a class Animal. If i have a farm, i want to find the animal in it, using its name. In each farm no two animals have the same name.
So i'd like to use some Colletion-Class in the class Farm. If i implement in Animal the interface Comparable, i can use the "TreeMap".
But there is one problem. I use as key the name of the animal. Assume now the farmer changes the name of the animal. Then the key in the TreeMap does NOT change with it. This is because changing a name of an animal, is the same as giving a NEW name to the animal (Strings are immutable).
Then i thought, maybe i can use StringBuffer, but StringBuffer is final, and does not implement the interface comparable. Someone has a better idea? Are do other better collectiontypes than treemap are useful?
Greets
Compugreen

Hello
I was wondering if you would have a 'good' solution
at the following problem.
Lets make it easy. I have a class named Farm. This
farm has animals. Each of them have there own name
and they have certain other characteristics. So there
is a class Animal. If i have a farm, i want to find
the animal in it, using its name. In each farm no two
animals have the same name.
So i'd like to use some Colletion-Class in the class
Farm. If i implement in Animal the interface
Comparable, i can use the "TreeMap".
But there is one problem. I use as key the name of
the animal. Assume now the farmer changes the name
e of the animal. Then the key in the TreeMap does NOT
change with it. This is because changing a name of an
animal, is the same as giving a NEW name to the
animal (Strings are immutable).
Then i thought, maybe i can use StringBuffer, but
StringBuffer is final, and does not implement the
interface comparable. Someone has a better idea? Are
do other better collectiontypes than treemap are
useful?
Greets
Compugreen
public class Name {
   private String name;
   public Name(String name) {
      change(name);
   public void change(String newName) {
      this.name = newName;
public class Animal {
   private Name name;
   public void changeName(String newName) {
      name.change(newName);
public class Farm {
   private TreeMap<Name, Animal> animals = new TreeMap<Name,Animal>(); // generics notation only to express what I mean...
}hth

Similar Messages

Compare a string and a binary value

Hi!
I would like to compare two passwords encoded into two different's LDAP directory.
For these two directories, I have not the same libraries, so that the encoded value of the first password returned is a String, and the second one is a binary.
Could you tell me if it is possible to compare them?
Thanks a lot!
Best regards

Hi dwg,
in LDAP directories, there is no encryption. There is
hash coding.
The same method of hashcoding is used in the two
directories, but we do not have (and we cannot)
decode the data.
We only have to compare the two hashcoded values.
About the "binary", you are right. It is a byte
array.
How about this function:
equals (<string parameter>, new String(<array
parameter>, "UTF8"))
do you think it is OK?
Thanks for your help!So you have a hashcode from one directory, and a plaintext String from the other? In that case you have to hash the plain String and then compare the two hashes. You can't turn a hash back into a String, which you seemed to point out when you said "but we do not have (and we cannot) decode the data."

I want to convert two image files into strings and than to compare them. This is easy, but how to mention where the difference exist?

I have two image file in bmp file format. How to convert them into string and to check if they are differnt or same. If different how to mention or find that where the difference exists. This idea have to be extented with video application as well.

Hi,
if you have vision, you could use the functin IMAQ Image to Array to have a 2D array of the pixel values.
You can then compare pixel by pixel; if your images come from a camera, I would recommend to set a treshold of acceptance.
This is a time consuming solution anyway.
Alternative methods:
1) Make a subtraction of the two images, the resulting image will be the difference of them
2 ) Use IMAQ LogDiff function (operators palette)
3) Calculate the histogram of both image and compare the histogram reports
Good luck,
Alberto

Help with String/ and or Array loading and comparing

Hi all,
I'm having some problems with trying to find the best way to achieve the following on a Poker Dealing program. I randomly shuffle a 52 card deck of playing cards and deal out 5 cards. Cool...
Now I have to go back thru the String and determine if my hand of cards contains
a pair
2 pair
3 of a kind
Full House
etc etc
I am trying to do String comparisons (there is an empty compareCards method in my code right now, but I'm getting a bit frustrated as to find the best way to do it... Would an array load in a separate method be a better way???? What I need to do is after I load my hand , is to display a message stating a pair, 3 of a kind , etc etc.....
Thanks in advance
Mike
Here is my code (please don't laugh too hard - I'm an old COBOL/Oracle guy):
// Card shuffling and dealing program
// Java core packages
import java.awt.*;
import java.awt.event.*;
// Java extension packages
import javax.swing.*;
public class DeckOfCards extends JFrame {
private Card deck[];
private Card hand[];
private int currentCard;
private JButton dealButton, shuffleButton;
private JTextArea outputArea ;
private JTextField displayField;
private JLabel statusLabel;
// set up deck of cards and GUI
public DeckOfCards()
super( "Poker Game" );
String faces[] = { "A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K" };
String suits[] = { "Hearts", "Diamonds", "Clubs", "Spades" };
String display = "" ;
deck = new Card[ 52 ];
currentCard = -1;
// populate deck with Card objects
for ( int count = 0; count < deck.length; count++ )
deck[ count ] = new Card( faces[ count % 13 ],
suits[ count / 13 ] );
// set up GUI and event handling
Container container = getContentPane();
container.setLayout( new FlowLayout() );
// shuffle button
shuffleButton = new JButton( "Shuffle cards" );
shuffleButton.addActionListener(
// anonymous inner class
new ActionListener() {
// shuffle deck
public void actionPerformed( ActionEvent actionEvent )
displayField.setText( "" );
shuffle();
displayField.setText( "The Deck is Shuffled" );
statusLabel.setText( "" );
} // end anonymous inner class
); // end call to addActionListener
container.add( shuffleButton );
// Deal button
dealButton = new JButton( "Deal Hand" );
dealButton.addActionListener (
// anonymous inner class
new ActionListener() {
// deal 5 cards
public void actionPerformed( ActionEvent actionEvent )
outputArea.setText( "" ) ;
displayField.setText( "" );
for ( int cctr = 1 ; cctr <= 5; cctr++ ){
Card dealt = dealCard();
if ( dealt != null ) {
outputArea.append( dealt.toString()+"\n" );
else {
displayField.setText( "No more cards left" );
statusLabel.setText( "Shuffle cards to continue" );}
} // end for structure
compareCards() ;
} // end action
} // end anonymous inner class
); // end call to addActionListener
container.add( dealButton );
outputArea = new JTextArea (10, 20) ;
outputArea.setEditable( false ) ;
container.add( outputArea ) ;
displayField = new JTextField( 20 );
displayField.setEditable( false );
container.add( displayField );
statusLabel = new JLabel();
container.add( statusLabel );
setSize( 275, 275 ); // set window size
show(); // show window
// shuffle deck of cards with one-pass algorithm
public void shuffle()
currentCard = -1;
// for each card, pick another random card and swap them
for ( int first = 0; first < deck.length; first++ ) {
int second = ( int ) ( Math.random() * 52 );
Card temp = deck[ first ];
deck[ first ] = deck[ second ];
deck[ second ] = temp;
dealButton.setEnabled( true );
public void compareCards()
public Card dealCard()
if ( ++currentCard < deck.length )
return deck[ currentCard ];
else {
dealButton.setEnabled( false );
return null;
// execute application
public static void main( String args[] )
DeckOfCards app = new DeckOfCards();
app.addWindowListener(
// anonymous inner class
new WindowAdapter() {
// terminate application when user closes window
public void windowClosing( WindowEvent windowEvent )
System.exit( 0 );
} // end anonymous inner class
); // end call to addWindowListener
} // end method main
} // end class DeckOfCards
// class to represent a card
class Card {
private String face;
private String suit;
// constructor to initialize a card
public Card( String cardFace, String cardSuit )
face = cardFace;
suit = cardSuit;
// return String represenation of Card
public String toString()
return face + " of " + suit;
} // end class Card

You could have the original face values as integers, thus Ace = 1, Jack = 11 (it'll be easy enough to display the proper values AJQK if you keep your string array and just display whatever corresponds to the value held in your int array).
Each player gets an array of five cards. You could the loop through each hand and increment values held in another array by one according to the value of the card. Haven't coded the following up but it should work I think.
// hand [ ] represents the cards held by that player
int handChecker [ ] = new int [14]
for (int counter = 0; counter < 5; ++ counter)
// 1st card is an Ace. handChecker [1] will be incrementd by one and so on
// 2nd card is a 9. handChecker[9] will be incremented by one.
handChecker[hand[counter]] += 1;
// Loop through the array handChecker to find pairs etc.
boolean pair = false;
bollean tofk = false;
for (int counter = 1; counter < 14; ++ counter)
if (handChecker[counter] == 2)
pair = true;
if (handChecker[counter] == 3)
tofk = true;
if (pair)
// player has a pair
if(tofk)
// player has three of a kind
if(pair && tofk)
// player has a full house

Compare string and string from db

I successfully queried a field from mysql into a jcombobox.
What I can't figure out is why:
String fromDB = comboBox.getSelectedItem().trim();
AND
String newString = "sameStringFromMySQL";are not equal. I already trimmed the text from the combo box but they are still not considered equal.
WHY???

just like how i described above.
(fromDB.equals(newString)) returns false.
Then they are not equal.
Most likely reasons:
-fromDB: This is starting with the text you think.
-fromDB: You aren't getting it from the right place.
-fromDB: You are modifying it before it gets to the comparison.
-NewString: Doesn't have the value you think.
-The comparison above isn't really the problem.
You can always print the bytes in any string by using the getBytes() method on String and printing out both strings just before the above comparison (not elsewhere.)

Field Symbols, Field String, and Field Group.

Hi,
Can you differentiate between filed symbols, field strings and field groups,
With regards,
Bharath Mohan B

Hi,
Field Symbols
Field symbols are placeholders or symbolic names for other fields. They do not physically reserve space for a field, but point to its contents. A field symbol cam point to any data object. The data object to which a field symbol points is assigned to it after it has been declared in the program.
Whenever you address a field symbol in a program, you are addressing the field that is assigned to the field symbol. After successful assignment, there is no difference in ABAP whether you reference the field symbol or the field itself. You must assign a field to each field symbol before you can address the latter in programs.
Field symbols are similar to dereferenced pointers in C (that is, pointers to which the content operator * is applied). However, the only real equivalent of pointers in ABAP, that is, variables that contain a memory address (reference) and that can be used without the contents operator, are reference variables in ABAP Objects.
All operations programmed with field symbols are applied to the field assigned to it. For example, a MOVE statement between two field symbols moves the contents of the field assigned to the first field symbol to the field assigned to the second field symbol. The field symbols themselves point to the same fields after the MOVE statement as they did before.
You can create field symbols either without or with type specifications. If you do not specify a type, the field symbol inherits all of the technical attributes of the field assigned to it. If you do specify a type, the system checks the compatibility of the field symbol and the field you are assigning to it during the ASSIGN statement.
Field symbols provide greater flexibility when you address data objects:
If you want to process sections of fields, you can specify the offset and length of the field dynamically.
You can assign one field symbol to another, which allows you to address parts of fields.
Assignments to field symbols may extend beyond field boundaries. This allows you to address regular sequences of fields in memory efficiently.
You can also force a field symbol to take different technical attributes from those of the field assigned to it.
The flexibility of field symbols provides elegant solutions to certain problems. On the other hand, it does mean that errors can easily occur. Since fields are not assigned to field symbols until runtime, the effectiveness of syntax and security checks is very limited for operations involving field symbols. This can lead to runtime errors or incorrect data assignments.
While runtime errors indicate an obvious problem, incorrect data assignments are dangerous because they can be very difficult to detect. For this reason, you should only use field symbols if you cannot achieve the same result using other ABAP statements.
For example, you may want to process part of a string where the offset and length depend on the contents of the field. You could use field symbols in this case. However, since the MOVE statement also supports variable offset and length specifications, you should use it instead. The MOVE statement (with your own auxiliary variables if required) is much safer than using field symbols, since it cannot address memory beyond the boundary of a field. However, field symbols may improve performance in some cases.
check the below links u will get the answers for your questions
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3860358411d1829f0000e829fbfe/content.htm
http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
http://searchsap.techtarget.com/tip/1,289483,sid21_gci920484,00.html
Syntax Diagram
FIELD-SYMBOLS
Basic form
FIELD-SYMBOLS <fs>.
Extras:
1. ... TYPE type
2. ... TYPE REF TO cif
3. ... TYPE REF TO DATA
4. ... TYPE LINE OF type
5. ... LIKE s
6. ... LIKE LINE OF s
7. ... TYPE tabkind
8. ... STRUCTURE s DEFAULT wa
The syntax check performed in an ABAP Objects context is stricter than in other ABAP areas. See Cannot Use Untyped Field Symbols ad Cannot Use Field Symbols as Components of Classes.
Effect
This statement declares a symbolic field called <fs>. At runtime, you can assign a concrete field to the field symbol using ASSIGN. All operations performed with the field symbol then directly affect the field assigned to it.
You can only use one of the additions.
Example
Output aircraft type from the table SFLIGHT using a field symbol:
FIELD-SYMBOLS <PT> TYPE ANY.
DATA SFLIGHT_WA TYPE SFLIGHT.
ASSIGN SFLIGHT_WA-PLANETYPE TO <PT>.
WRITE <PT>.
Addition 1
... TYPE type
Addition 2
... TYPE REF TO cif
Addition 3
... TYPE REF TO DATA
Addition 4
... TYPE LINE OF type
Addition 5
... LIKE s
Addition 6
... LIKE LINE OF s
Addition 7
... TYPE tabkind
Effect
You can define the type of the field symbol using additions 2 to 7 (just as you can for FORM parameters (compare Defining the Type of Subroutine Parameters). When you use the ASSIGN statement, the system carries out the same type checks as for USING parameters of FORMs.
This addition is not allowed in an ABAP Objects context. See Cannot Use Obsolete Casting for FIELD SYMBOLS.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Defining Types Using STRUCTURE.
Effect
Assigns any (internal) field string or structure to the field symbol from the ABAP Dictionary (s). All fields of the structure can be addressed by name: <fs>-fieldname. The structured field symbol points initially to the work area wa specified after DEFAULT.
The work area wa must be at least as long as the structure s. If s contains fields of the type I or F, wa should have the structure s or at least begin in that way, since otherwise alignment problems may occur.
Example
Address components of the flight bookings table SBOOK using a field symbol:
DATA SBOOK_WA LIKE SBOOK.
FIELD-SYMBOLS <SB> STRUCTURE SBOOK
DEFAULT SBOOK_WA.
WRITE: <SB>-BOOKID, <SB>-FLDATE.
Related
ASSIGN, DATA
Additional help
Declaring Field Symbols
FIELD GROUPS
are used to hold/handle large amount of data when the internal table are not useful
we use EXTRACT statement, HEADER structure in them
see the example
REPORT demo_extract.
NODES: spfli, sflight.
FIELD-GROUPS: header, flight_info, flight_date.
START-OF-SELECTION.
INSERT: spfli-carrid spfli-connid sflight-fldate
            INTO header,
          spfli-cityfrom spfli-cityto
            INTO flight_info.
GET spfli.
EXTRACT flight_info.
GET sflight.
EXTRACT flight_date.
END-OF-SELECTION.
SORT STABLE.
LOOP.
    AT FIRST.
      WRITE / 'Flight list'.
      ULINE.
    ENDAT.
    AT flight_info WITH flight_date.
      WRITE: / spfli-carrid , spfli-connid, sflight-fldate,
               spfli-cityfrom, spfli-cityto.
    ENDAT.
    AT flight_date.
      WRITE: / spfli-carrid , spfli-connid, sflight-fldate.
    ENDAT.
    AT LAST.
      ULINE.
      WRITE: cnt(spfli-carrid), 'Airlines'.
      ULINE.
    ENDAT.
ENDLOOP.
FIELD STRING is nothing but a string with one row of records.
Reward points if useful
regards
Anji

Sort array list and using comparable

With the following code I would like to setup a score object for the current player.
Change it to a string(Is it correct to say parse it to a string type)
Then add it to the arraylist.
So I can sort the array list according to the string size.
That's why I have the variables in that order.
So if 3 players have the same amount of guesses, they can be positioned on the high score list according to their gameTime.
//create score object
               Score currentScore = new Score(guessCount, gameTime, name);
               String currentScoreToString = currentScore.toString();
               //add score to arrayList
               scores.add(currentScoreToString);So the error message says " The method add(Score) in the type arrayList <Score> is not applicable for the arguments(string)"
Now, I understand that, I would like to know if there is another way to achieve what I am trying to do.
Is the string idea I am trying here possible? is it practical or should I use comparable?
I have looked at comparable, but I don't get it.
Will my Score class implement comparable. I am looking at an example with the following code.
Employee.java
public class Employee implements Comparable {
    int EmpID;
    String Ename;
    double Sal;
    static int i;
    public Employee() {
        EmpID = i++;
        Ename = "dont know";
        Sal = 0.0;
    public Employee(String ename, double sal) {
        EmpID = i++;
        Ename = ename;
        Sal = sal;
    public String toString() {
        return "EmpID " + EmpID + "\n" + "Ename " + Ename + "\n" + "Sal" + Sal;
    public int compareTo(Object o1) {
        if (this.Sal == ((Employee) o1).Sal)
            return 0;
        else if ((this.Sal) > ((Employee) o1).Sal)
            return 1;
        else
            return -1;
ComparableDemo.java
import java.util.*;
public class ComparableDemo{
    public static void main(String[] args) {
        List ts1 = new ArrayList();
        ts1.add(new Employee ("Tom",40000.00));
        ts1.add(new Employee ("Harry",20000.00));
        ts1.add(new Employee ("Maggie",50000.00));
        ts1.add(new Employee ("Chris",70000.00));
        Collections.sort(ts1);
        Iterator itr = ts1.iterator();
        while(itr.hasNext()){
            Object element = itr.next();
            System.out.println(element + "\n");
}The thing I don't understand is why it returns 0, 1 or -1(does it have to do with the positioning according to the object is being compared with?)
What if I only use currentScore in a loop which loops every time the player restarts?
//create score object
               Score currentScore = new Score(guessCount, gameTime, name);
               String currentScoreToString = currentScore.toString();
               //add score to arrayList
               scores.add(currentScoreToString);Also why there is a method compareTo, and where is it used?
Thanks in advance.
Edited by: Implode on Oct 7, 2009 9:27 AM
Edited by: Implode on Oct 7, 2009 9:28 AM

jverd wrote:
Implode wrote:
I have to hand in an assignment by Friday, and all I have to do still is write a method to sort the array list. Okay, if you have to write your own sort method, then the links I provided may not be that useful. They show you how to use the sort methods provided by the core API. You COULD still implement Comparable or Comparator. It would just be your sort routine calling it rather than the built-in ones.
You have two main tasks: 1) Write a method that determines which of a pair of items is "less than" the other, and 2) Figure out a procedure for sorting a list of items.
The basic idea is this: When you sort, you compare pairs of items, and swap them if they're out of order. The two main parts of sorting are: 1) The rules for determining which item is "less than" another and 2) Determining which pairs of items to compare. When you implement Comparable or create a Comparator, you're doing #1--defining the rules for what makes one object of your class "less than" another. Collections.sort() and other methods in the core API will call your compare() or compareTo() method on pairs of objects to produce a sorted list.
For instance, if you have a PersonName class that consists of firstName and lastName, then your rules might be, "Compare last names. If they're different, then whichever lastName is less indicates which PersonName object is less. If they're the same, then compare firstNames." This is exactly what we do in many real-life situations. And of course the "compare lastName" and "compare firstName" steps have their own rules, which are implemented by String's compareTo method, and which basically say, "compare char by char until there's a difference or one string runs out of chars."
Completely independent of the rules for comparing two items is the algorithm for which items get compared and possibly swapped. So, if you have 10 Whatsits (W1 through W10) in a row, and you're asked to sort them, you might do something like this:
Compare the current W1 to each of W2 through W10 (call the current one being compared Wn). If any of them are less than W1, swap that Wn with W1 and continue on, comparing the new W1 to W(n+1) (that is, swap them, and then compare the new first item to the next one after where you just swapped.)
Once we reach the end of the list, the item in position 1 is the "smallest".
Now repeat the process, comparing W2 to W3 through W10, then W3 to W4 through W10, etc. After N steps, the first N positions have the correct Whatsit.
Do you see how the comparison rules are totally independent of the algorithm we use to determine which items to compare? You can define one set of comparison rules ("which item is less?") for Whatsits, another for Strings, another for Integers, and use the same sorting algorithm on any of those types of items, as long as you use the appropriate comparison rules.Thanks ;)
massive help
I understand that now, but I am clueless on how to implement it.
Edited by: Implode on Oct 7, 2009 10:56 AM

Search for string and move decimal

Hello,
I am trying to write code that will search for a fractional string within an array and convert it from mV to V so it can be properly compared to the other fractional string numbers in the array.
I have an array that outputs x iterations each with a minimum and maximum column including several different types of decimal strings (negative/positive with several decimal places) each ending with either mV and V (example string: -725.543mV).
I then split the array into columns containing the minumum and maximum values of each iteration. I want to compare the minimum values of each iteration and find the most minimum, and do the same thing with the maximum values.
Unfortunatley the way I'm doing it, when I convert from fractional string to number it removes the V or mV unit label but does not convert the number from mV to V. so it compares -725.543mV with -52.334V as -725.543 & -52.334 thus declaring the mV value the most minimum. I need the program to recognize that mV is less than V or search each array for values labeled with mV and move the decimal place so it is in standard V format.
The unit label is actually part of the string and not the display (as you can see in the code I've attached) and I understand this is a little tricky with the way I have to do it. But this is a dumbed down chunk of code I will eventually incorporate into my larger program which reads the values and their units from several different types of oscilloscopes. The Scopes output the values as strings as they appear on the screen and don't differentiate between mV and V unless they are told to output the units which just tags them on the end of the string.
I'm sorry for the large post. SO to sum up I need to search an array to make sure all values have the same units, if they don't I need to convert each value to the proper unit and output the max and min from the resulting array. my code is attached. Thank you for your help.
Solved!
Go to Solution.
Attachments:
File manipulation.vi ‏15 KB

crossrulz wrote:
jcarmody wrote:
camerond wrote:
Sorry, Jim, that's not quite right. You forgot to consider significant figures (your third min is not quite right). [...]
Good catch, but, really?
That "Finally!" comes out to -5569492V to me. Holy crap. -5.569492MV! I think there's a problem there.
Carp! Stupid negative numbers, shouldn't be allowed. Put a piece of duck tape over the place for that negative sign, that'll fix it.
I'll get back, it's now a matter of principle.
Jim, how does your algorithm do when there are 8 or 9 sig figs, say -56.9492345mV? (Yep, too lazy to draw it in myself.)
Cameron
To err is human, but to really foul it up requires a computer.
The optimist believes we are in the best of all possible worlds - the pessimist fears this is true.
Profanity is the one language all programmers know best.
An expert is someone who has made all the possible mistakes.
To learn something about LabVIEW at no extra cost, work the online LabVIEW tutorial(s):
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Question about Classes, Abstract Classes and Interfaces.

I have been experimenting with Classes, Abstract Classes and Interfaces and wonder if anyone can explain this to me.
I was looking for a way to assign a value to a variable and then keep it fixed for the session and have devised this.
First I create an abstract class like this:
public abstract class DatabaseConnection {
private static String ServerName = null;
public static void setServerName(String serverName) {
          ServerName = serverName;
     public static String getServerName() {
          return ServerName;
}and then I created an interface
public interface DatabaseAccess {
     String servername = DatabaseConnection.getServerName();
}And finally the class itself with some test lines in it so I could see what was going on:
public class CreateDatabase extends DatabaseConnection implements DatabaseAccess {
     public static void main (String args[]){
          new CreateDatabase();
     public CreateDatabase(){
          setServerName("Server Name 1");
          System.out.println ("Before update ");
          System.out.println ("ServerName from Interface           = " + servername);
          System.out.println ("ServerName from Abstract Class = " + getServerName());
          System.out.println ("After update ");
          setServerName("Server Name 2");
          System.out.println ("ServerName from Interface           = " + servername);
          System.out.println ("ServerName from Abstract Class = " + getServerName());
          System.out.println ("==========================");
}The output I get from the above is:
Before update
ServerName from Interface           = Server Name 1
ServerName from Abstract Class = Server Name 1
After update
ServerName from Interface           = Server Name 1
ServerName from Abstract Class = Server Name 2
==========================I also tried this in another class which calls the above class to see if I get the same effect
public class CheckDatabaseAccess {
     public static void main (String args[]){
          new CreateDatabase();
          CreateDatabase.setServerName("Server 3");
          System.out.println("CreateDatabase "+CreateDatabase.servername);
          CreateDatabase.setServerName("Server 4");
          System.out.println("CreateDatabase "+CreateDatabase.servername);
          CreateDatabase.setServerName("Server 5");
          System.out.println("CreateDatabase "+CreateDatabase.servername);
}The output of which is this:
Before update
ServerName from Interface           = Server Name 1
ServerName from Abstract Class = Server Name 1
After update
ServerName from Interface           = Server Name 1
ServerName from Abstract Class = Server Name 2
==========================
CreateDatabase Server Name 1
CreateDatabase Server Name 1
CreateDatabase Server Name 1Can anyone explain why I appear to only be able to change or set the ServerName only the once?
Is this the correct way to do it? If it is it's exactly what I am looking for, a way to set the value of variable once in a session and then prevent it being changed.
Or is there a better way of doing this.
What I want to use this for is for example, storing the accesses to a database on a server. I won't know what server the database will be stored on nor what the database is called so I create an INI file which stores this information in encrypted format, which is set by the database administrator. It occurs to me I can use this method to then retrieve that data once and once only from the INI file and use that throughout the life of the session to access the database.
Any help appreciated
Regards
John

Not gonna read all of it, but this jumps out:
public abstract class DatabaseConnection {
private static String ServerName = null;
public interface DatabaseAccess {
     String servername = DatabaseConnection.getServerName();
}You have two completely separate variables (with two different names, for that matter, since you were inconsistent in your capitalization, but it wouldn't make a difference if they did have the same name with the same case). And the one in the interface is implicitly public, static, and final.
Anytime you refer to "servername" through a reference of type DatabaseAccess, it refers to the one declared in the interface.
Anytime you refer to "ServerName" inside the DatabaseConnection class, it refers to the one declared in that class.

Jdbc, string and SQL Server's varbinary

Hi,
I have a problem, of course otherwise I wouldn't ask for help :)
So I entered some test data in SQL Server Tables with some varbinary
types for primary keys. The fields that where put with newid() are the
problem. Normaly the data should have been put there with jdbc but also
with newid(). When I try to match them against the same
data but that was first get from db through jdbc as a string the
comaparision fails! If for example I get the value for an pk column and
I put in variable x_pk when I try the select in java:
... sql = "Select * from" + tableName + "where pk = " + castSQL(x_pk)
where castSQL() is for varbinary data type cast from string:
     * Method to cast the strings with pk for sql server.
     * @param str ( String ) the string wilth the pk
     private String castSQL( String str ){
                    String s = str.trim();
                    String ss = "cast (" + asString(s) + "as varbinary)";
     return ss.trim();
and asString() put the ' around it,
this select will not work even if the values are the same!!!
But probalby are not quite the same, something happens on the road in
getting it from db to string and then cast it to varbinary to compare
against the value from db.
So if someone has already encountered this please help me.
Regards,
Adrian

You can't. They're lost forever in the black abyss of the forums.

Difference between Abstarct Class and Interface

HI,
Here is a simple one for the gurus but quite important for me.
What is the difference b/w an Interface and an abstract class?
Why do we need each one of them?
I would appreciate if you people can give examples of each so that I amy understand fully
Thanks in advance...

A normal class (not abstract) has a special behaviour, like java.awt.Frame. A Frame is a frame no matter how you subclass it. If you create a subclass it will still be able to be displayed by calling it's show method. So by using a normal class you can create a type of class.
An abstract class does the same, but it leaves some of the code unwritten. For instance java.lang.Number. This class is abstract becuase it has no knowledge of how to store the number in memory. But it knows that it is a number, and any subclass will still be a number. You could create a subclass of Number that can hold the time in milliseconds and checks your system clock to see what the time is, it could also have methods that return the time in another country, but it would still be just a Number.
An interface is a way to describe what an object can do, not what it is. So with java.lang.Comparable as an example you can make any class comparable. This means that no matter what type of object you have, it can be compared with other objects. So you can have a subclass of Frame that can be compared with other windows. Or a subclass of Number that can be compared with other Numbers. You can even compare those two different types if you like. So you could compare a window with a number.
That is the difference between abstract classes and interfaces.
I hope you could follow my arguments, it isn't an easy subject,
Daniel

Reading lines and then comparing them

Hi,
I want to read two lines of a single file and then compare them. Right now, I've implemented:
String line = null;
String currentLine = null;
String prevLine = null;
BufferedReader bf = new BufferedReader(new FileReader(fileA));
while ((line=bf.readLine()) != null)
            currentLine = line;
            prevLine = line;
        }I understand that this code returns the same line, but I was just hoping that maybe someone could point me in the right direction. Thanks in advance.

800343 wrote:
remember to use .equals() for equality comparisons. For comparing objects' states (contents), yes, absolutely. That's what it's for.
The == tends to act funny, even in situations where it should obviously work.No it doesn't. It works exactly as it's supposed to. It compares the value on the left side to the value on the right side. Always. Whether those values are primitives or references, it behaves the same way.

Delegation and interface

i m reading Grand's Patterns in java, he says that delegation and interface patterns are often used together, however i wasnot able to find any references, i cant quite see why that is?

GoF discusses delegation. They don't make it a pattern, rather they use it in several of their patterns. Their example of a Window delegating its area operation to a Rectangle and then being able to switch to using a Circle at runtime is dependent on Rectangle and Circle having the same "type", ie implementing the same interface. Here's a Java version of the delegation example on page 20 of "Design Patterns"
public class Window implements TwoD
     TwoD my2D = new Rectangle(1,1);     // we delegate area to this TwoD
     // switch to circular delegate
     void useCircle(double radius)
     {my2D = new Circle(radius);}
     // switch to rectangular delegate
     void useRectangle(double width, double height)
     {my2D = new Rectangle(width,height);}
     // our area method uses the delegate
     public double area()
     {return my2D.area();}
     public static void main(String[] args)
          Window w = new Window();     // construct a window
          w.useRectangle(4.0, 6.0);     // set the shape to a rectangle
          System.out.println("area of rectangular window="+w.area());
          w.useCircle(2.5);               // set the shape to a circle
          System.out.println("area of circular window="+w.area());
// 2 d shape used by Window, Circle and REctangle
interface TwoD
     double area();     // requires an area method
// rectangular shape
class Rectangle implements TwoD
     double width, height;
     Rectangle(double w, double h)
          width = w;
          height = h;
     public double area(){return width*height;}
// circular shape
class Circle implements TwoD
     double radius;
     Circle(double r)
          radius = r;
     public double area(){return Math.PI*radius*radius;}
}

Diff b/w msg mapping and interface mapping

hi
i have some doubt's:
1. diff b/w msg mapping and interface mapping
2. What is product in SLD? usually who creates the product,technical,business system??
thx in advance..

hI Smartsoft General User ,
The following r excellent websites on mapping which differentiate msg mapping and interface mapping in detail:
Excellent PDF Document on Mapping
http://help.sap.com/bp_bpmv130/Documentation/Operation/MappingXI30.pdf
Mapping Development with the ABAP Workbench
http://help.sap.com/saphelp_nw04/helpdata/en/10/5abb2d9df242f6a62e22e027a6c382/content.htm
ABAP Mappings
http://help.sap.com/saphelp_nw04/helpdata/en/ba/e18b1a0fc14f1faf884ae50cece51b/content.htm
how to create a flat file out of an IDoc-XML by means of an ABAP mapping program and the J2EE File Adapter.
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/46759682-0401-0010-1791-bd1972bc0b8a
How to Use ABAP Mapping in XI 3.0
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/e3ead790-0201-0010-64bb-9e4d67a466b4
These r excellent websites in SLD:
How ToHandle the SLD for SAP XI
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/9e76e511-0d01-0010-5c9d-9f768d644808
How ToHandle Caches in SAP XI 3.0
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/1a69ea11-0d01-0010-fa80-b47a79301290
http://www.sap-press.de/download/dateien/751/sap_press_exchange_infra_engl.pdf
cheers!
gyanaraj
****Pls reward points if u find this helpful

What is diff b/w abstarct and interface

what is diff b/w abstarct and interface in real time where we come across, give a best real time example

I think there have been lots of threads in this forum discussing interfaces and abstract classes.
http://forum.java.sun.com/thread.jspa?forumID=256&threadID=389830
http://forum.java.sun.com/thread.jspa?forumID=54&threadID=5120074
http://forum.java.sun.com/thread.jspa?forumID=54&threadID=499077
http://forum.java.sun.com/thread.jspa?forumID=31&threadID=546668
Interfaces define a contract for what an implementing class should provide. Abstract classes do the same but they can also provide some common part of the implementation.

Stringes and interface Comparable

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