Initializing array constructor to 0

I have created a stats class, but I am not sure how to initialize the array constructor to be all zeros. It is a single interger array that can hold 50 values.

int[] array = new int[50];Each array element will be initialized to zero.
The Java� Tutorial - Arrays

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Varray of Objects: Initializing, Instantiation, Constructors, ORA-06531

This is supposed to fill a varray with ten objects, calling methods in those objects and populating the objects from queries, then display fields from the objects via methods. Error message is in comment at bottom. Any ideas?
-- Enable screen I/O
SET SERVEROUTPUT ON SIZE 1000000
SET VERIFY OFF
-- object spec
CREATE OR REPLACE TYPE employee4 AS OBJECT
o_ename CHAR (20 char),
o_empno NUMBER (4),
o_sal NUMBER (10),
o_thisno NUMBER (4),
MEMBER FUNCTION get_o_ename RETURN CHAR, MEMBER PROCEDURE set_o_ename (o_thisno IN number),
MEMBER FUNCTION get_o_empno RETURN NUMBER, MEMBER PROCEDURE set_o_empno (o_thisno IN number),
MEMBER FUNCTION get_o_sal RETURN NUMBER, MEMBER PROCEDURE set_o_sal (o_thisno IN number),
CONSTRUCTOR FUNCTION employee4 (o_ename CHAR,o_empno NUMBER,o_sal NUMBER,o_thisno NUMBER) RETURN SELF AS RESULT
-- object body
CREATE OR REPLACE TYPE BODY employee4 AS
CONSTRUCTOR FUNCTION employee4 (o_ename IN CHAR,
o_empno IN NUMBER,
o_sal IN NUMBER,
o_thisno IN NUMBER)
RETURN SELF AS RESULT IS
BEGIN
SELF.o_ename := o_ename;
SELF.o_empno := o_empno;
SELF.o_sal := o_sal;
SELF.o_thisno := o_thisno;
RETURN;
END;
-- gets
MEMBER FUNCTION get_o_ename RETURN CHAR IS
BEGIN
RETURN self.o_ename;
END;
MEMBER FUNCTION get_o_empno RETURN NUMBER IS
BEGIN
RETURN self.o_empno;
END;
MEMBER FUNCTION get_o_sal RETURN NUMBER IS
BEGIN
RETURN self.o_ename;
END;
-- sets
MEMBER PROCEDURE set_o_ename(o_thisno IN number) IS
BEGIN
SELECT ename INTO SELF.o_ename FROM emp WHERE empno = SELF.o_thisno;
END;
MEMBER PROCEDURE set_o_empno(o_thisno IN number) IS
BEGIN
SELECT empno INTO SELF.o_empno FROM emp WHERE empno = SELF.o_thisno;
END;
MEMBER PROCEDURE set_o_sal(o_thisno IN number) IS
BEGIN
SELECT sal INTO SELF.o_sal FROM emp WHERE empno = SELF.o_thisno;
END;
END;
DECLARE
-- a varray of employees
TYPE emp_varray1 IS VARRAY(10) OF employee4;
varray_of_emps EMP_VARRAY1;
-- List of EMPNO's in order of appearance in EMP table (for cross-referencing, single-line retrieval)
TYPE MYCREF_VARRAY IS VARRAY(10) OF NUMBER(4);
varray_mycref MYCREF_VARRAY := MYCREF_VARRAY(NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);
-- make a variable to store one empno
thisno NUMBER(4);
-- make a counter
counter INT;
-- query variables for the set calls
q_ename CHAR(20 CHAR);
q_empno NUMBER(4);
q_sal NUMBER(10);
BEGIN
-- Put the first 10 EMPNO's in my cref array
SELECT empno BULK COLLECT INTO varray_mycref FROM emp WHERE ROWNUM < 11;
-- Use a loop to retrieve the first 10 objects in the "emp" table and put them in the varray of objects
FOR counter IN 1..10 LOOP
thisno := varray_mycref(counter);
varray_of_emps(counter).set_o_ename(thisno);
varray_of_emps(counter).set_o_empno(thisno);
varray_of_emps(counter).set_o_sal(thisno);
END LOOP;
-- Use another loop to display the information in the reverse order.
FOR counter in REVERSE 1..10 LOOP
dbms_output.put_line((varray_of_emps(counter).get_o_ename()) || CHR(9) || (varray_of_emps(counter).get_o_empno()) || CHR(9) || (varray_of_emps(counter).get_o_sal()));
END LOOP;
END;
This results in the following response in SQL*PLUS:
Type created.
Type body created.
DECLARE
ERROR at line 1:
ORA-06531: Reference to uninitialized collection
ORA-06512: at line 33

Hi,
From metalink:
Cause: An element or member function of a nested table or varray was
referenced (where an initialized collection is needed) without the
collection having been initialized.
Action: Initialize the collection with an appropriate constructor or
whole-object assignment.
ORA 6531 Reference to uninitialized collection (Doc ID 48912.1)

Initializing array of user-defined class

I have a need to make an array of my own classes, simply to make a database organized.
First, I defined my class at the start of the program:
public class FBase
String FName = "";
String FDate = "";
int FNameLength = 0;
int FDateLength = 0;
int status = 0; // value of 0, 1, 2
} FExample = New FBase;
This gives me one instance of the class, FExample.
Now I can store data thus:
FExample.FName = "Jones";
FExample.FDate = "1934";
FExample.FNameLength = 5;
FExample.FDateLength = 4;
FExample.status = 2;
What I would like is an array of such instances of this class.
I have followed the standard procedure for initializing an array, but my efforts are not accepted.
In place of the line above initializing one instance in FExample, I have tried -- both at the top of the program and in public void init() -- the following code:
FBase[] Example = New FBase[200];
FBase Example[] = New FBase[200];
FBase[] Example;
Example = new FBase[200];
None of these are accepted. How do I do this?

Alright -- I found one problem and solved it, but I still have another problem, pretty much the same problem I thought I was facing at the start, but now a little better defined.
At first, my class did not work even with one instantiation, let alone when I tried to instantiate an array of the class. I dound that I did not have a constructor, and I need a constructor if I am to create an instance of the class (I am learning ...). So, the class now looks like this:
public class FBase
String FName = "";
String FDate = "";
public FBase(){} // constructor
Now the following line of code works:
FBase FExample = new FBase();
I am able to use FExample.FName and FExample.FDate as proper variables.
My problem still exists when I try to instantiate an array of the class. In place of the above line of code, I have tried this:
FBase[] FExample = new FBase[200];
The compiler accepts it, but now FExample[0].FName and FExample[0].FDate are not recognized as proper variables, and nothing goes on when I try to use them in the program.
Any ideas?
Edited by: vanhoey on Jun 27, 2008 12:38 PM
Edited by: vanhoey on Jun 27, 2008 12:40 PM

ARRAY constructor is slow

I am developing some code to call some stored procdures that have been developed by a customer. They require us to initialize an empty 2D array and send it into the procedure.
I noticed that the bigger I make the array, the slower the constructor takes to execute.
ARRAY[][] elems = new ARRAY[ 1 ][ 16 ]; => 1-2 seconds
ARRAY[][] elems = new ARRAY[ 10 ][ 16 ]; => 9-10 seconds
These aren't huge arrays, so I am wondering if there is anything I can do to increase performance?
ArrayDescriptor desc =
ArrayDescriptor.createDescriptor( "APPS.L_CUSTOMER_ARRAY", conn.getConnection() );
ARRAY[][] elems = new ARRAY[ 1 ][ 16 ];
ARRAY newArray = new ARRAY( desc, conn.getConnection(), elems );=> this is really slow!
Thanks!

What language are you programming in? that doesn't look like PL/SQL.
cheers, APC

Initializing array of Object T

Is there any way to initialize an array using the class tokens?
In my case I want to create a new T[100]; without (initializing any specific elements that is) - it does not seem to function very well...

Not really, because T isn't known at run time (erasure) so you can't create an array of a specific type this way.
If you've got a class object for T you can use Array.newInstance() and cast it to
T[]. (Though you'll get an "unchecked cast" warning).

Initializing array elements on a static initialization block

Hello,
I have this class:
class Foo{
    public static Wing[] flights = new Wing[20]; //initialize with null Wing references
    static { //static initialization block - begin
        for(Wing w : flights){ //for each Wing slot on the array,
            w = new Wing();      //create a Wing object and refer to it
        } // static init block - endThe code above creates a Wing array, and the static init block should create 20 Wing objects on the array slots, but the objects are lost when I try to use it in the main method on the same class Foo:
    public static void main(String[] args){
         System.out.println(flights[3].name); //will throw NullPointerException -> Array elements have not been initialized
    }How is that possible? The init code for(Wing w : flights) looks like has created copies of the objects, and not just references to the same object. If I change the static init block to the "old-fashioned for loop"
for (int i=0; i < flights.length; i++){
flights[i] = new Wing();then it works.
But I think that the problem is not on the kind of for loop itself, because if I use same static initialization statement, with for (Wing w : flights) on the main method, instead of in a separate init block, the array gets populated with solid objects.
Any ideas of what I am doing wrong?
Java version: 5.0

I think I got it. I am reseting the reference to point to a new Object in the heap instead of the array slot. :-P

Initializing arrays with non-default values

Hi,
I have a large array (300+ elements) and want it to be filled with all -1 at the start and not with 0.
A couple of (bad) ideas of mine:
- using an expression "array[0] = -1, array[1] = -1, ..." (a lot of typing work)
- using a for loop with an expression "array[Locals.k] = -1" (very slow)
- getting the array from "somewhere else" like e.g. a LabVIEW VI (cumbersome)
Is there some expression syntax I can use?

You can use SetElements(Locals.d,-1) where d is the array.

Initializing array of objects

This is my beginning effort to initialize an array of objects, but the compiler messages seem to lead me astray. What is the easiest way to do this, or can't it be done in a manner similar to this?
Do I have to do it from a program loop or something?
private static void testWidNum() {
class testPair { double dbl; int nsf; }
testPair[] testNums = new testPair[] { {999999999.,5}, {9999.,5} };
This should be an easy answer, compared to the one to which I didn't get any reponses.
dewayne

Probably I may write it like this.
public class SomeClass
private void testWidNum() {
    testPair[] testNums = new testPair[]{
                                   new testPair(9999, 5),
                                   new testPair(9999, 5),
                                   new testPair(9999, 5)
class testPair{
    testPair(double _dbl, int _nsf)
        dbl = _dbl;
        nsf = _nsf;
   double dbl; int nsf;
}

Initializing arrays?

Hello!
In a VI have an empty 2D-array (3 columns, x rows),
in which I want to insert a new row. The first time
I start the VI, the row is correctly inserted. When
I start the VI again, the array-insertion-VI doesn't
insert anything. Ideas if I have to initialize
the target array in any way?
Thanks in advance, Michael.

Hi,
if the array is a front panel control/indicator you have to fill in some data in that area (even if it's 0.00) to "activate" those cells for future use.
To be sure that everything it's done properly, initialize the array with default values for a specific number of rows and columns before any other operation.

How to insert a 2D array into the end of X axis of the initial array?

Hi, friends, I have a question and look for an advice. I have several input data, each of which has 4 rows and unknow columns. Each time I receive the input, I need to combine it to all of the previous ones by adding it to the end of X axis of the previous combined data. I must do it because, later, I need to run my model and my model read input for each column of 4 rows. How should I do it? Also, should I initiate an array before reading all of the inputs? The inputs are F32 format. Thank you very much for any of your advice.

Building a 2D array row-by-row is easy. You either use "build array" if you need to update the indicator during the run, or you simply autoindex at the loop boundary (FOR or WHILE).
Two possibilities are shown in the attached image. If your arrays are getting large and you use a while loop, there are possibilities that are more memory efficient. You would initialize a 2D array (e.g. filled with NaNs) of an upper boundary of the final expected size, then replace rows as you go.
(Notice that if you use autoindexing on a FOR loop, the final size is known from the beginning so memory can be allocated efficiently)
Message Edited by altenbach on 11-01-2006 09:19 AM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
AppendRows.png ‏5 KB

Initializing Array of JLabels

This one's got me scratching my head. The critical lines of code are:
     final JLabel[] labelTable = new JLabel[3][9];
     labelTable[0][0] = new JLabel("Item Name");And then there are several more lines like the second. The problem I'm having is that, on every line like the second, I get two errors: one complaining that there isn't a closing ] immediately after the very first opening one, and then another error that I just assume is caused by the first error FUBARing the line's syntax.
Why on earth would the compiler not want a value in the array element brackets? I did just create the array, right? It knows labelTable is an array, or it should...
I've tried removing the "final", and I've tried removing the " = new JLabel[3][9]", and neither fixes the problem. Any ideas?

There's not a lot more than what I've already provided...
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Gui implements ActionListener {
     final JLabel[][] labelTable = new JLabel[9][3];
     labelTable[0][0] = new JLabel("Item Name");
     labelTable[0][1] = new JLabel("Cost");
     labelTable[0][2] = new JLabel("Reserved By:");
     /* What follows will be replaced by a file read when I'm good and ready. */
     labelTable[1][0] = new JLabel("Book about Cheez-Its");
     labelTable[1][1] = new JLabel("$$");
     labelTable[1][2] = new JLabel("Santa Claus");
     labelTable[2][0] = new JLabel("Amazing Electronic Gadget");
     labelTable[2][1] = new JLabel("$$$");
     labelTable[2][2] = new JLabel("none");
     labelTable[3][0] = new JLabel("Ye Holye Thumbtack");
     labelTable[3][1] = new JLabel("$");
     labelTable[3][2] = new JLabel("Clarence Thomas");Those are lines 7 through 26. The lines before 7 are a documentation comment. The lines after 26 are standard, straight-out-of-the-Tutorial methods for implementing the rest of the GUI (look'n'feel String, initLookAndFeel(), createAndShowGUI()...) and also setting a couple rows of buttons. The code for the buttons compiles fine. I just get 24 errors corresponding to those twelve initializations of labelTable[x][y].

Initializing Array in a Unique Manner

Hi All,
I'm new on this and have tried for several hours how to do the following "simple" thing without any success. I'm using a cDAQ 9171 with a NI 9263 analog output module.
My Problem: I need to start the following program when Start button is pushed. Please, in order of priority I'm giving you what I have to do.
1. Analog output from an array that haves fixed values. Let it be 5 ; 4 ; 3 ; 2 ; 3 ; 4 . So I need to stay 1min in each value and then repeat the whole array for 10 times more.
I Tried with the attached project, but it only generated a 1V signal, even when the appended array was changing...I don't know what happened.
2. I wanted to create automatically the array i mentioned before. But it gave me so much headache that i left it.
Thanks in advance for your help.
Solved!
Go to Solution.
Attachments:
v0.3.zip ‏24 KB

Take advantage of auto-indexing tunnels to break out the data in your array. And if you use 1 channel 1 sample rather than N channels 1 sample, you won't need to take that scalar value and build it back into an array.
Attachments:
fte v0.3MOD.vi ‏37 KB

URGENT - initializing array

how can i copy the values from a fime into an array ?

Oh I see. File.
That depends on the data type of the array... do you want to store Strings, int, Objects...?

Initializing Array

Why does this work:
public class Test
     private int[][] array;
     public Test()
          int[][] a =
          {{0, 1},
           {1, 0}};
          array = a;
}But this doesnt:
public class Test
     private int[][]array;
     public Test()
          array =
          {{0, 1},
           {1, 0}};
}Thanks ahead of time.

Just to correct my terminology here - and I think it gives an insight into why the legal syntax is defined in that particular way - I should have said that the code I posted "assigns the reference to point to a new array object with those values" rather than that it "reinitializes" the array.

Using arrays as type for bind variable

Hi all,
I have this stored procedures that takes an array of strings as an argument:
CREATE OR REPLACE PACKAGE mypackage AS
TYPE StringArray IS VARRAY(100) OF VARCHAR2(16);
PROCEDURE doSomething(v_strings IN StringArray);
END;
My java code looks something like:
String[] strings = ...;
CallableStatement cs = connection.prepareCall("CALL mypackage.doSomething(?)");
cs.setObject(1, strings, java.sql.Types.ARRAY);
calling the setObject method throws a SQLException: invalid column type.
I have tried to change the call to:
cs.setArray(1, new SqlStringArray(strings))
where SqlStringArray is a wrapper around String[] that implements the java.sql.Array interface. This however throws a ClassCastException in oracle.jdbc.driver.OraclePreparedStatement. The latter is assuming it is receiving a class that implements yet another interface I guess.
I also tried:
cs.setObject(1, strings, java.sql.Types.VARCHAR);
but that also throws a SqlException: invalid conversion requested
Does anybody know how to bind String[] into a PreparedStatement?
Any help is appreciated.
Rudi.

Made some progress. I am getting the OracleConnection from the WrappedConnection. This is a temporary solution for me so I would appreciate a final solution from anybody.
I am now constructing a oracle.sql.ARRAY with an appropriate oracle.sql.ArrayDescriptor. I have found out that the type must be defined on a global level rather than in the scope of the package. Would be good if an Oracle expert could confirm that but I am happy to live with that.
The IN parameter is correctly bound using the ARRAY instance but I am getting the following error when actually executing the statement:
ORA-06512: Reference to uninitialized collection: at "BLUETEST_MYPACKAGE", line 57
Now I have found quite some problem descriptions with that ORA error but all are dealing with OUT parameters that were not correctly initialized, i.e. the array constructor had not been called. In my case however, the array is initialized at by the java code and then bount to the sql statement. You would expect that the jdbc driver takes care of correctly initializing the PL/SQL collection wouldn't you.
Does anybody know if I need to do anything extra?
Many thanks,
Rudi.

Initializing array constructor to 0

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