Difference between Null and null?
What is the difference between null and NULL?
When is each used?
Thanks,
veryConfused wrote:
There is a null in java, but no NULL. null means no value. However, when assigning value, the following is different:Although the empty String has no special role. Null means, the referential type is not assigned (doesn't refer) to a specific object. The empty String is just another object though, so seeing it or pointing it out as something special when it actually isn't at all (no more special than new Integer(0) or new Object[0]) just adds to the confusion.
Similar Messages
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Difference between -1 and null in the targettype filed
Hi
Could anyone advise what is the difference between -1 and null in the targettype filed in marketing documents?
For example, in Sales Quotation - Rows (QUT1) table, I found for some open sales quotations, the field is null however the DB help file suggest the default value is -1 so I suppose it should be -1 for open documents.
Many thanks for your advisory.Hi, Qian!
I investigated that "-1" value appears in targettype field in Sales Quotation Rows (QUT1 table) when you Dublicate a Sales Quotation document (Ctrl + D). And NULL value appears when you create a new document without dublicating.
In case you want to equal these 2 "empty"-values using T-SQL, you can use ISNULL(targettype, -1) function - this will give you -1 for both the "empty"-values
HTH!
Message was edited by: Aleksey Kuznetsov -
Difference between void and null?
wht is da difference between void and null w.r.t java?
corlettk wrote:
Why do you care, unless you're implementing a java compiler or JVM?Wow, you sure do suck at helping out in a forum. Why even make this post? You're not helping the OP any, and you made yourself look like a tool.
To the op:
Null is java's version of a null value. Java's version is more strict then many other languages, and will not work in a boolean expression or anywhere code expects a real and not null value. It's simply null.
Void is java's way of declaring no return type on a method. Methods that are void take no 'return' statement and if one is provided will cause a fatal error. The exception to this is using 'return' without a value, which returns control to the caller of the method.
Observe:
//this method returns an int
public int return_int(){
int value = 5;
return value;
//this method does not return an int
public void return_nothing(){
int another_value = 123;
System.out.println("Here's the value: " + return_int());
//this method does not return anything
public void nothing_returned(){
return_nothing();
return;
System.out.println("This line never gets printed; the method returned control already!");
} -
Hello everyone.
I have a requirement of distinguish zero values from null values. It seems the Visual Composer treats null values as zero values.
I have the following query in BI:
month..................ProcessA..................ProcessB................ProcessC
01.2009...........................10..............................................................5
02.2009.............................................................................................0
03.2009............................3...............................................................1
04.2009............................0...............................................................2
I'm trying to represent this in a line chart in visual composer. The axis has the month, and I defined 3 dataseries, one for each Process (A, B and C).
The issue here is that I don't have nothing in ProcessB, but the VC represents in the chart that dataserie has a line along the zero value. This is wrong. If don't have nothing in ProcessB, not even the value zero, this dataserie should not be represented (printed) in the chart.
Does anyone have any idea how to contourn this?
Thanks,
Diogo.Hi Talia,
I'm also working with that workaround although the system kind of behaves in a strange way sometimes...
Here's what I did:
Created another query with the accumulated values along the month but without displaying the month, like this:
QueryB:
ProcessA.........ProcessB...........ProcessC
13...............................................8
This query is like a pre-query. First the input is being sent to this pre-queryB that returns a table (not visible) and also the output of this pre-query does a *submit to the first (original) query.
In the original query I use a dataserie with the following formula:
NVAL(IF(ISNULL(#ID[ACC9LL]@ProcessB),'',@ProcessB_value))
The "#ID[ACC9LL]@ProcessB" is the reference (first executed) of the pre-query (queryB) that has the accumulated value, i.e., if along all the months if exists or not any value. If it doesn't exists, returns nothing (''), else it returns the actual value (@ProcessB_value). Since it is an IF, it returns a text, I have to convert it to numeric value therefore I used NVAL() function.
But this also doesn't refresh nicely with chart effects. I have to disabled the effects of the chart (interpolate, fold, slide) to work properly. Also, the scale of the Y axis is not being well adjusted (the auto-adjust option), does not work also fine if the first dataserie returned by the formula is the null value (''). So I also have to ensure that the first dataserie contains in fact anything (the returned value of the formula can't be null). If so (the first dataserie contains any value), this works fine.
Also you can't return false. False will be treated as 0, and thus will do the all dataserie be treated as zero along the X axis, and that is not true. With '', this will force to don't display any line for that dataserie.
Diogo. -
Difference between cancel_flag IS NULL and cancel_flag ='N'
Hi ,
Please clarify Difference between cancel_flag IS NULL and cancel_flag ='N' in PO Headers .
Because from front end cancel check box is unchecked in abobe both the cases . We can see cancel check box status only in Help>Diagnostics>Examine .
Thanks in Advance
KiranHi Kiran,
The is no difference between cancel_flag with 'null' and 'N' but cancel field contain Null if it is generated through auto create and it contains 'N' if Purchase order raised without PR .
I hope you understand.
Regards,
Sravani.M
Edited by: 855855 on Nov 9, 2012 5:49 AM -
Difference between IS NULL and = NULL
Hello Guys,
In 10gR2 what is the difference between IS NULL and = NULL
Thanks,
ImranJust don't use the second, because the comparison operator = cannot deal with NULLs as you (probably) hope it can:
SQL> create table t1 as select rownum as id, 'test' as word from dual connect by level<=2;
Table created.
SQL> update t1 set word=null where id=1;
1 row updated.
SQL> commit;
Commit complete.
SQL> select * from t1;
ID WORD
1
2 test
SQL> select * from t1 where word is null;
ID WORD
1
SQL> select * from t1 where word = null;
no rows selectedKind regards
Uwe Hesse
http://uhesse.wordpress.com -
What is the difference between string != null and null !=string ?
Hi,
what is the difference between string != null and null != string ?
which is the best option ?
Thanks
user8729783Like you've presented it, nothing. There is no difference and neither is the "better option".
-
What is the difference between tkprof and explainplan
Hi,
what is the difference between tkprof and explainplan.Execution Plans and the EXPLAIN PLAN Statement
Before the database server can execute a SQL statement, Oracle must first parse the statement and develop an execution plan. The execution plan is a task list of sorts that decomposes a potentially complex SQL operation into a series of basic data access operations. For example, a query against the dept table might have an execution plan that consists of an index lookup on the deptno index, followed by a table access by ROWID.
The EXPLAIN PLAN statement allows you to submit a SQL statement to Oracle and have the database prepare the execution plan for the statement without actually executing it. The execution plan is made available to you in the form of rows inserted into a special table called a plan table. You may query the rows in the plan table using ordinary SELECT statements in order to see the steps of the execution plan for the statement you explained. You may keep multiple execution plans in the plan table by assigning each a unique statement_id. Or you may choose to delete the rows from the plan table after you are finished looking at the execution plan. You can also roll back an EXPLAIN PLAN statement in order to remove the execution plan from the plan table.
The EXPLAIN PLAN statement runs very quickly, even if the statement being explained is a query that might run for hours. This is because the statement is simply parsed and its execution plan saved into the plan table. The actual statement is never executed by EXPLAIN PLAN. Along these same lines, if the statement being explained includes bind variables, the variables never need to actually be bound. The values that would be bound are not relevant since the statement is not actually executed.
You don’t need any special system privileges in order to use the EXPLAIN PLAN statement. However, you do need to have INSERT privileges on the plan table, and you must have sufficient privileges to execute the statement you are trying to explain. The one difference is that in order to explain a statement that involves views, you must have privileges on all of the tables that make up the view. If you don’t, you’ll get an “ORA-01039: insufficient privileges on underlying objects of the view” error.
The columns that make up the plan table are as follows:
Name Null? Type
STATEMENT_ID VARCHAR2(30)
TIMESTAMP DATE
REMARKS VARCHAR2(80)
OPERATION VARCHAR2(30)
OPTIONS VARCHAR2(30)
OBJECT_NODE VARCHAR2(128)
OBJECT_OWNER VARCHAR2(30)
OBJECT_NAME VARCHAR2(30)
OBJECT_INSTANCE NUMBER(38)
OBJECT_TYPE VARCHAR2(30)
OPTIMIZER VARCHAR2(255)
SEARCH_COLUMNS NUMBER
ID NUMBER(38)
PARENT_ID NUMBER(38)
POSITION NUMBER(38)
COST NUMBER(38)
CARDINALITY NUMBER(38)
BYTES NUMBER(38)
OTHER_TAG VARCHAR2(255)
PARTITION_START VARCHAR2(255)
PARTITION_STOP VARCHAR2(255)
PARTITION_ID NUMBER(38)
OTHER LONG
DISTRIBUTION VARCHAR2(30)
There are other ways to view execution plans besides issuing the EXPLAIN PLAN statement and querying the plan table. SQL*Plus can automatically display an execution plan after each statement is executed. Also, there are many GUI tools available that allow you to click on a SQL statement in the shared pool and view its execution plan. In addition, TKPROF can optionally include execution plans in its reports as well.
Trace Files and the TKPROF Utility
TKPROF is a utility that you invoke at the operating system level in order to analyze SQL trace files and generate reports that present the trace information in a readable form. Although the details of how you invoke TKPROF vary from one platform to the next, Oracle Corporation provides TKPROF with all releases of the database and the basic functionality is the same on all platforms.
The term trace file may be a bit confusing. More recent releases of the database offer a product called Oracle Trace Collection Services. Also, Net8 is capable of generating trace files. SQL trace files are entirely different. SQL trace is a facility that you enable or disable for individual database sessions or for the entire instance as a whole. When SQL trace is enabled for a database session, the Oracle server process handling that session writes detailed information about all database calls and operations to a trace file. Special database events may be set in order to cause Oracle to write even more specific information—such as the values of bind variables—into the trace file.
SQL trace files are text files that, strictly speaking, are human readable. However, they are extremely verbose, repetitive, and cryptic. For example, if an application opens a cursor and fetches 1000 rows from the cursor one row at a time, there will be over 1000 separate entries in the trace file.
TKPROF is a program that you invoke at the operating system command prompt in order to reformat the trace file into a format that is much easier to comprehend. Each SQL statement is displayed in the report, along with counts of how many times it was parsed, executed, and fetched. CPU time, elapsed time, logical reads, physical reads, and rows processed are also reported, along with information about recursion level and misses in the library cache. TKPROF can also optionally include the execution plan for each SQL statement in the report, along with counts of how many rows were processed at each step of the execution plan.
The SQL statements can be listed in a TKPROF report in the order of how much resource they used, if desired. Also, recursive SQL statements issued by the SYS user to manage the data dictionary can be included or excluded, and TKPROF can write SQL statements from the traced session into a spool file.
How EXPLAIN PLAN and TKPROF Aid in the Application Tuning Process
EXPLAIN PLAN and TKPROF are valuable tools in the tuning process. Tuning at the application level typically yields the most dramatic results, and these two tools can help with the tuning in many different ways.
EXPLAIN PLAN and TKPROF allow you to proactively tune an application while it is in development. It is relatively easy to enable SQL trace, run an application in a test environment, run TKPROF on the trace file, and review the output to determine if application or schema changes are called for. EXPLAIN PLAN is handy for evaluating individual SQL statements.
By reviewing execution plans, you can also validate the scalability of an application. If the database operations are dependent upon full table scans of tables that could grow quite large, then there may be scalability problems ahead. On the other hand, if large tables are accessed via selective indexes, then scalability may not be a problem.
EXPLAIN PLAN and TKPROF may also be used in an existing production environment in order to zero in on resource intensive operations and get insights into how the code may be optimized. TKPROF can further be used to quantify the resources required by specific database operations or application functions.
EXPLAIN PLAN is also handy for estimating resource requirements in advance. Suppose you have an ad hoc reporting request against a very large database. Running queries through EXPLAIN PLAN will let you determine in advance if the queries are feasible or if they will be resource intensive and will take unacceptably long to run. -
Differences between awt and swing
Ive written the following code, however Ive implemented the gui in awt rather then swing. Ive been told it hs too be in swing. What is the difference between swing and awt what will I need to change in my program so that its done using swing rather then the awt? Heres the code:
// pp.java
// Grant Brown
// 22/02/02
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
// =========================================================
// Class: pp
// This class drives the customer manager. It contains the
// main method which gets called as soon as this application
// begins to run.
// =========================================================
class pp extends Frame implements ActionListener
// Container of customer objects
private Vector customers = new Vector (100);
// List of names component. (Must specify java.awt in
// front of List to distinguish the List class in the
// java.awt package from the List class in the java.util
// package.)
private java.awt.List names = new java.awt.List ();
// Delete and update button components.
private Button delete;
private Button update;
// Default constructor.
public pp ()
// Assign "Paper Round Manager" to title bar of frame window.
super ("Paper Round Manager");
// Add a listener that responds to window closing
// events. When this event occurs (by clicking on the
// close box in the title bar), save customers and exit.
addWindowListener (new WindowAdapter ()
public void windowClosing
(WindowEvent e)
saveCustomers ();
System.exit (0);
// Place an empty label in the north part of the frame
// window. This is done to correct an AWT positioning
// problem.
Label l = new Label ();
add ("North", l);
// Place the names component in the center part of the
// frame window.
add ("Center", names);
// Create a panel object to hold four buttons.
Panel p = new Panel ();
Button b;
// Add an Insert button to the Panel object and register
// the current pp object as a listener for button events.
p.add (b = new Button ("Insert"));
b.addActionListener (this);
// Add a Delete button to the Panel object and register
// the current pp object as a listener for button events.
p.add (delete = new Button ("Delete"));
delete.addActionListener (this);
// The Delete button should be disabled until there is at
// least one customer to delete.
delete.setEnabled (false);
// Add an Update button to the Panel object and register
// the current pp object as a listener for button events.
p.add (update = new Button ("Update"));
update.addActionListener (this);
// The Update button should be disabled until there is at
// least one customer to update.
update.setEnabled (false);
// Add a Finish button to the Panel object and register
// the current customer object as a listener for button events.
p.add (b = new Button ("Finish"));
b.addActionListener (this);
// Add the panel object to the frame window container.
add ("South", p);
// Set the background of the frame window container to
// lightGray
setBackground (Color.lightGray);
// Set the size of the frame window container to 400
// pixels horizontally by 200 pixels vertically.
setSize (400, 200);
// Allow the user to resize the frame window.
setResizable (true);
// Load all contacts.
loadCustomers ();
// Make sure that the frame window is visible.
setVisible (true);
public void actionPerformed (ActionEvent e)
if (e.getActionCommand ().equals ("Delete"))
delete ();
else
if (e.getActionCommand ().equals ("Finish"))
saveCustomers ();
System.exit (0);
else
if (e.getActionCommand ().equals ("Insert"))
insert ();
else
update ();
public Insets getInsets ()
// Return an Insets object that describes the number of
// pixels to reserve as a border around the edges of the
// frame window.
return new Insets (10, 10, 10, 10);
public static void main (String [] args)
// Create a new pp object and let it do its thing.
new pp ();
private void delete ()
// Obtain index of selected contact item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a contact if no contact item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Remove the contact item from the names component.
names.remove (index);
// Remove the Customer object from the contacts Vector
// object.
customers.remove (index);
// If there are no more customers ...
if (customers.size () == 0)
delete.setEnabled (false);
update.setEnabled (false);
else
// Make sure that the first contact item in the names
// list is highlighted.
names.select (0);
private void insert ()
// Create an Insert data entry form to enter information
// for a new customer.
DataEntryForm def = new DataEntryForm (this, "Insert");
// If the bOk Boolean flag is set, this indicates the user
// exited the form by pressing the Ok button.
if (def.bOk)
// Create a Contact object and assign information from
// the form to its fields.
Customer temp = new Customer ();
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.round = new String (def.round.getText ());
temp.address = new String (def.address.getText ());
temp.phone = new String (def.phone.getText ());
// Add a new customer item to the names component.
names.add (temp.name + ", " + temp.publication);
// Add the Customer object to the contacts Vector
// object.
customers.add (temp);
// Make sure that the Delete and Update buttons are
// enabled.
delete.setEnabled (true);
update.setEnabled (true);
// Destroy the dialouge box.
def.dispose ();
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ===========================================================
// Load all contacts from contacts.dat into the contacts
// Vector object. Also, make sure that the last name/first
// name from each contact is combined into a String object and
// inserted into the names component - as a contact item.
// ===========================================================
private void loadCustomers ()
FileInputStream fis = null;
try
fis = new FileInputStream ("Customers.dat");
DataInputStream dis = new DataInputStream (fis);
int nCustomers = dis.readInt ();
for (int i = 0; i < nCustomers; i++)
Customer temp = new Customer ();
temp.name = dis.readUTF ();
temp.publication = dis.readUTF ();
temp.round = dis.readUTF ();
temp.address = dis.readUTF ();
temp.phone = dis.readUTF ();
names.add (temp.name + ", " + temp.publication);
customers.add (temp);
if (nCustomers > 0)
delete.setEnabled (true);
update.setEnabled (true);
catch (IOException e)
finally
if (fis != null)
try
fis.close ();
catch (IOException e) {}
// Make sure that the first contact item in the names list
// is highlighted.
names.select (0);
// ========================================================
// Save all Customer objects from the customer Vector object
// to customer.dat. The number of customerss are saved as an
// int to make it easy for loadCustomers () to do its job.
// ========================================================
private void saveCustomers ()
FileOutputStream fos = null;
try
fos = new FileOutputStream ("customers.dat");
DataOutputStream dos = new DataOutputStream (fos);
dos.writeInt (customers.size ());
for (int i = 0; i < customers.size (); i++)
Customer temp = (Customer) customers.elementAt (i);
dos.writeUTF (temp.name);
dos.writeUTF (temp.publication);
dos.writeUTF (temp.round);
dos.writeUTF (temp.address);
dos.writeUTF (temp.phone);
catch (IOException e)
MsgBox mb = new MsgBox (this, "PP Error",
e.toString ());
mb.dispose ();
finally
if (fos != null)
try
fos.close ();
catch (IOException e) {}
private void update ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a customer if no customer item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Obtain a reference to the customer object (from the
// customers Vector object) that is associated with the
// index.
Customer temp = (Customer) customers.elementAt (index);
// Create and display an update entry form.
DataEntryForm def = new DataEntryForm (this, "Update",
temp.name,
temp.publication,
temp.round,
temp.address,
temp.phone);
// If the user pressed Ok...
if (def.bOk)
// Update the customer information in the customers
// Vector object.
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.round = new String (def.round.getText ());
temp.address = new String (def.address.getText ());
temp.phone = new String (def.phone.getText ());
// Make sure the screen reflects the update.
names.replaceItem (temp.name + ", " + temp.publication,
index);
// Destroy the dialouge box.
def.dispose ();
// Make sure that the first customer item in the names
// list is highlighted.
names.select (0);Ive doen pretty much what you said burt now my program isnt working at all. The window comes up but instead of doing something when you click the button it just throws shit loads of exceptions. Heres my abridged code
// pp.java
// Grant Brown
// 22/02/02
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
// =========================================================
// Class:PP
// This class drives the Paper Round manager. It contains the
// main method which gets called as soon as this application
// begins to run.
// =========================================================
class pp extends JFrame implements ActionListener
// Container of customer objects (one object per customer)
private Vector customers = new Vector (100);
// List of names component. (Must specify java.awt in
// front of List to distinguish the List class in the
// java.awt package from the List class in the java.util
// package.)
private java.awt.List names = new java.awt.List ();
// Delete and update button components.
private JButton delete;
private JButton update;
// Default constructor.
public pp ()
// Assign Contact Manager to title bar of frame window.
super ("Paper Round Manager");
// Add a listener that responds to window closing
// events. When this event occurs (by clicking on the
// close box in the title bar), save contacts and exit.
addWindowListener (new WindowAdapter ()
public void windowClosing
(WindowEvent e)
saveCustomers ();
System.exit (0);
// Place an empty label in the north part of the frame
// window. This is done to correct an AWT positioning
// problem. (One thing that you'll come to realize as
// you work with the AWT is that there are lots of bugs.)
JLabel l = new JLabel ();
getContentPane().add ("North", l);
// Place the names component in the center part of the
// frame window.
getContentPane().add ("Center", names);
// Create a panel object to hold four buttons.
JPanel p = new JPanel ();
JButton b;
// Add an Insert button to the Panel object and register
// the current cm object as a listener for button events.
p.add (b = new JButton ("Insert"));
b.addActionListener (this);
// Add a Delete button to the Panel object and register
// the current cm object as a listener for button events.
p.add (delete = new JButton ("Delete"));
delete.addActionListener (this);
// The Delete button should be disabled until there is at
// least one contact to delete.
delete.setEnabled (false);
// Add an Update button to the Panel object and register
// the current cm object as a listener for button events.
p.add (update = new JButton ("Update"));
update.addActionListener (this);
// The Update button should be disabled until there is at
// least one contact to update.
update.setEnabled (false);
// Add a Finish button to the Panel object and register
// the current cm object as a listener for button events.
p.add (b = new JButton ("Finish"));
b.addActionListener (this);
// Add the panel object to the frame window container.
getContentPane().add ("South", p);
// Set the background of the frame window container to
// lightGray (to give a pleasing effect).
setBackground (Color.lightGray);
// Set the size of the frame window container to 400
// pixels horizontally by 200 pixels vertically.
setBounds (50, 100, 400, 200);
// Do not allow the user to resize the frame window.
loadCustomers ();
// Load all contacts.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Make sure that the frame window is visible.
setVisible (true);
public void actionPerformed (ActionEvent e)
if (e.getActionCommand ().equals ("Delete"))
delete ();
else
if (e.getActionCommand ().equals ("Finish"))
saveCustomers ();
System.exit (0);
else
if (e.getActionCommand ().equals ("Insert"))
insert ();
else
update ();
public Insets getInsets ()
// Return an Insets object that describes the number of
// pixels to reserve as a border around the edges of the
// frame window.
return new Insets (10, 10, 10, 10);
public static void main (String [] args)
// Create a new cm object and let it do its thing.
new pp ();
private void delete ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a contact if no contact item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Remove the customer item from the names component.
names.remove (index);
// Remove the Customer object from the contacts Vector
// object.
customers.remove (index);
// If there are no more customers ...
if (customers.size () == 0)
delete.setEnabled (false);
update.setEnabled (false);
else
// Make sure that the first contact item in the names
// list is highlighted.
names.select (0);
private void insert ()
// Create an Insert data entry form to enter information
// for a new contact.
DataEntryForm def = new DataEntryForm (this, "Insert");
// If the bOk Boolean flag is set, this indicates the user
// exited the form by pressing the Ok button.
if (def.bOk)
// Create a Customer object and assign information from
// the form to its fields.
Customer temp = new Customer ();
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.address = new String (def.address.getText ());
temp.round = new String (def.round.getText ());
temp.phone = new String
(def.phone.getText ());
// Add a new customer item to the names component.
names.add (temp.publication + ", " + temp.address);
// Add the Customer object to the contacts Vector
// object.
customers.add (temp);
// Make sure that the Delete and Update buttons are
// enabled.
delete.setEnabled (true);
update.setEnabled (true);
// Destroy the dialog box.
def.dispose ();
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ===========================================================
// Load all customers from customers.dat into the customers
// Vector object. Also, make sure that the last name/first
// name from each contact is combined into a String object and
// inserted into the names component - as a contact item.
// ===========================================================
private void loadCustomers ()
FileInputStream fis = null;
try
fis = new FileInputStream ("customers.dat");
DataInputStream dis = new DataInputStream (fis);
int nCustomers = dis.readInt ();
for (int i = 0; i < nCustomers; i++)
Customer temp = new Customer ();
temp.name = dis.readUTF ();
temp.publication = dis.readUTF ();
temp.address = dis.readUTF ();
temp.round = dis.readUTF ();
temp.phone = dis.readUTF ();
names.add (temp.publication + ", " + temp.address);
customers.add (temp);
if (nCustomers > 0)
delete.setEnabled (true);
update.setEnabled (true);
catch (IOException e)
finally
if (fis != null)
try
fis.close ();
catch (IOException e) {}
// Make sure that the first customer item in the names list
// is highlighted.
names.select (0);
// ========================================================
// Save all customer objects from the contacts Vector object
// to customers.dat. The number of contacts are saved as an
// int to make it easy for loadCustomers () to do its job.
// ========================================================
private void saveCustomers ()
FileOutputStream fos = null;
try
fos = new FileOutputStream ("customers.dat");
DataOutputStream dos = new DataOutputStream (fos);
dos.writeInt (customers.size ());
for (int i = 0; i < customers.size (); i++)
Customer temp = (Customer) customers.elementAt (i);
dos.writeUTF (temp.name);
dos.writeUTF (temp.publication);
dos.writeUTF (temp.address);
dos.writeUTF (temp.round);
dos.writeUTF (temp.phone);
catch (IOException e)
MsgBox mb = new MsgBox (this, "PP Error",
e.toString ());
mb.dispose ();
finally
if (fos != null)
try
fos.close ();
catch (IOException e) {}
private void update ()
// Obtain index of selected customer item from the names
// component.
int index = names.getSelectedIndex ();
// If no item was selected, index is -1. We cannot update
// a customer if no customer item in the names component was
// selected - because we would have nothing to work with.
if (index != -1)
// Obtain a reference to the Customer object (from the
// customer Vector object) that is associated with the
// index.
Customer temp = (Customer) customers.elementAt (index);
// Create and display an update entry form.
DataEntryForm def = new DataEntryForm (this, "Update",
temp.name,
temp.publication,
temp.address,
temp.round,
temp.phone);
// If the user pressed Ok...
if (def.bOk)
// Update the customer information in the customers
// Vector object.
temp.name = new String (def.name.getText ());
temp.publication = new String (def.publication.getText ());
temp.address = new String (def.address.getText ());
temp.round = new String (def.round.getText ());
temp.phone = new String (def.phone.getText ());
// Make sure the screen reflects the update.
names.replaceItem (temp.publication + ", " + temp.address,
index);
// Destroy the dialog box.
def.dispose ();
// Make sure that the first customer item in the names
// list is highlighted.
names.select (0);
// ========================================================
// Class: Customer
// This class describes the contents of a business customer.
// ========================================================
class Customer
public String name;
public String publication;
public String address;
public String round;
public String phone;
// ==========================================================
// Class: DataEntryForm
// This class provides a data entry form for entering customer
// information.
// ==========================================================
class DataEntryForm extends JDialog implements ActionListener
// bOk is a boolean flag. When true, it indicates that
// the Ok button was pressed to terminate the dialog box
// (as opposed to the Cancel button).
public boolean bOk;
// The following components hold the text that the user
// entered into the visible text fields.
public JTextField name;
public JTextField publication;
public JTextField address;
public JTextField round;
public JTextField phone;
public void actionPerformed (ActionEvent e)
// If the user pressed the Ok button, indicate this
// by assigning true to bOk.
if (e.getActionCommand ().equals ("Ok"))
bOk = true;
// Destroy the dialog box and return to the point
// just after the creation of the DataEntryForm object.
dispose ();
public DataEntryForm (JFrame parent, String title)
// Call the other constructor. The current constructor
// is used for insert operations. The other constructor
// is used for update operations.
this (parent, title, "", "", "", "", "");
public DataEntryForm (JFrame parent, String title,
String name, String publication,
String address, String round,
String phone)
// Initialize the superclass layer.
super (parent, title, true);
// Choose a grid bag layout so that components can be more
// accurately positioned. (It looks nicer.)
setLayout (new GridBagLayout ());
// Add appropriate first name, last name, phone, fax, and
// email components to the current DataEntryForm container.
// (Remember, DataEntryForm is a subclass of Dialog.
// Dialog is a container. Therefore, DataEntryForm
// inherits the ability to be a container.)
addComponent (this, new JLabel ("Name: "), 0, 0, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.name = new JTextField (15);
addComponent (this, this.name, 1, 0, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.name.setText (name);
addComponent (this, new JLabel ("Publications: "), 0, 1, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.publication = new JTextField (15);
addComponent (this, this.publication, 1, 1, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.publication.setText (publication);
addComponent (this, new JLabel ("Address "), 0, 2, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.address = new JTextField (15);
addComponent (this, this.address, 1, 2, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.address.setText (address);
addComponent (this, new JLabel ("Round No "), 0, 3, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.round = new JTextField (15);
addComponent (this, this.round, 1, 3, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.round.setText (round);
addComponent (this, new JLabel ("Phone Number "), 0, 4, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.WEST);
this.phone = new JTextField (15);
addComponent (this, this.phone, 1, 4, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
if (title.equals ("Update"))
this.phone.setText (phone);
addComponent (this, new JLabel (""), 0, 5, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
addComponent (this, new JLabel (""), 1, 5, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
JButton b;
// Add an Ok button to this container.
addComponent (this, b = new JButton ("Ok"), 0, 6, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
b.addActionListener (this);
// Add a Cancel button to this container.
addComponent (this, b = new JButton ("Cancel"), 1, 6, 1, 1,
GridBagConstraints.NONE,
GridBagConstraints.CENTER);
b.addActionListener (this);
// Set the size of the dialog window to 250 pixels
// horizontally by 200 pixels vertically.
setSize (250, 200);
// Do not allow users to resize the dialog window.
setResizable (false);
// Make sure that the dialog window is visible.
setVisible (true);
private void addComponent (Container con, Component com,
int gridx, int gridy,
int gridw, int gridh, int fill,
int anchor)
// Get the current layout manager. It is assumed to
// be a GridBagLayout object.
LayoutManager lm = con.getLayout ();
// Create a GridBagConstraints object to make it
// possible to customize component positioning.
GridBagConstraints gbc = new GridBagConstraints ();
// Assign the x and y grid positions.
gbc.gridx = gridx;
gbc.gridy = gridy;
// Assign the number of grid blocks horizontally and
// vertically that are occupied by the component.
gbc.gridwidth = gridw;
gbc.gridheight = gridh;
// Specify the component's resize policy (fill) and
// the direction in which the component is positioned
// when its size is smaller than available space (anchor).
gbc.fill = fill;
gbc.anchor = anchor;
// Set the new constraints that the grid bag layout
// manager will use.
((GridBagLayout) lm).setConstraints (com, gbc);
// Add the component to the container.
con.add (com);
// ===========================================================
// Class: MsgBox
// This class displays a message box to the user. The message
// is usually an error message. The user must press the Ok
// button to terminate the message box.
// ===========================================================
class MsgBox extends JDialog implements ActionListener
public void actionPerformed (ActionEvent e)
// Terminate the dialog box in response to the user
// pressing the Ok button.
dispose ();
public MsgBox (JFrame parent, String title, String msg)
// Initialize the superclass layer.
super (parent, title, true);
// Store the msg argument in a Label object and add
// this object to the center part of the dialog window.
JLabel l = new JLabel (msg);
add ("Center", l);
// Create a Button object and add it to the south part
// of the dialog window.
JButton b = new JButton ("Ok");
add ("South", b);
// Make the current object a listener to events that
// occur as a result of the user pressing the Ok
// button.
b.addActionListener (this);
// Make sure that the Ok button has the focus.
b.requestFocus ();
// Do not allow users to resize the dialog window.
setResizable (false);
// Allow the layout manager to choose an appropriate
// size for the dialog window.
pack ();
// Make sure that the dialog window is visible.
setVisible (true);
} -
Re: The difference between update() and doFinal() in ClassCipher
Hi Guys,
I found this topic,
The difference between update() and doFinal() in ClassCipher
during a Google Search. I need your help, because I'm working on a project for an university exam.
It's about a Client FTP that sends and received files with the content crypted.
I'm using DES Encryption with "DES/CBC/PKCS5Padding".
I have this doubt: when it's correct to uso the doFinal method? At the last block of the file, or after it? (for encryption)
And during the decryption, how can I use the result of the doFinal operation?Reposting with {code} tags
capagira87 wrote:
Ok these are the functions:
public void CodificaInvia (String cd, String filename, SecretKey Key) // it opens, codes and sends to the server the content of the file 512 bytes per time
int returncode=0;
Socket DataSock = null;
FileInputStream fis = null;
byte [] text = null;
try {
DataSock = new Socket (servAddress,22);
ObjectInputStream cin = new ObjectInputStream (DataSock.getInputStream());
ObjectOutputStream out = new ObjectOutputStream (DataSock.getOutputStream());
byte[] iv = new byte[] { (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A };
AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, Key, paramSpec);
fis = new FileInputStream (cd+File.separator+filename);
int size = fis.available();
if ((size%8)==0)
text = new byte [size];
} else {
do {
size++;
} while ((size%8)!=0);
text = new byte [size];
fis.read(text,0,fis.available());
byte [] ciphertext = cipher.doFinal(text);
out.writeInt(ciphertext.length);
int numblock = ciphertext.length/512;
int resto = ciphertext.length%512;
out.writeInt(numblock);
out.writeInt(resto);
byte [] tempblock = new byte [512];
for (int conta=0; conta<numblock; conta++)
for (int i=0; i<512; i++)
tempblock=ciphertext[(conta*512)+i];
out.write(tempblock);
out.flush();
if (resto > 0) // this block works if the file size is not multiple of 512
java.util.Arrays.fill (tempblock, (byte) 0);
int h= numblock*512;
for (int i=0; i<resto; i++)
tempblock[i]=ciphertext[h+i];
out.write (tempblock);
out.flush();
System.out.println ("OK!");
} catch (Exception e)
e.printStackTrace();
public void RicezioneDecodifica (String filename, SecretKey Key) // in this function I receive the file blocks, I decrpyt them and I save the decrypted text into a file
Socket DataSock = null;
byte [] buffer=null; // it saves the received data
String Plaintext = new String (); // it saves the deciphered text
try {
ServerSocket ss2 = new ServerSocket (TRANSMISSION_PORT);
DataSock = ss2.accept();
ObjectOutputStream out = new ObjectOutputStream (DataSock.getOutputStream());
ObjectInputStream cin = new ObjectInputStream (DataSock.getInputStream());
byte[] iv = new byte[] { (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A };
AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
Cipher dcipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
dcipher.init(Cipher.DECRYPT_MODE, Key, paramSpec);
int size = cin.readInt();
int numblock = cin.readInt();
int resto = cin.readInt();
if ((size%8)!=0)
do{
size++;
} while ((size%8)!=0);
int ByteLetti=0; // counter of read bytes
buffer = new byte [size];
for (int conta=0; conta<numblock; conta++)
int a=cin.available();
byte [] tempblock = new byte [a];
cin.read(tempblock, 0, a);
for (int i=0; i<a; i++)
buffer[ByteLetti+i]=tempblock[i];
ByteLetti=ByteLetti+a;
byte[] texttmp=dcipher.update(tempblock);
String tmp = new String (texttmp, "UTF8");
Plaintext=Plaintext+tmp;
if (resto>0)
int a = cin.available();
byte [] tempblock;
if ((a%8)>0)
do {
a++;
} while ((a%8)!=0);
tempblock = new byte [a];
cin.read(tempblock, 0, cin.available());
byte[] texttmp = dcipher.doFinal(tempblock);
String tmp = new String (texttmp, "UTF8");
Plaintext = Plaintext+tmp;
ObjectOutputStream oos = new ObjectOutputStream (new FileOutputStream (filename));
oos.writeChars(Plaintext);
oos.flush();
oos.close();
} catch (Exception e)
e.printStackTrace(); -
What's the difference between equals() and compareTo() method
I'm confused between the two method from String class ,,, what's the main difference between equals() and compareTo() method?
API docs give quite clear information IMHO
public boolean equals(Object anObject)
Compares this string to the specified object. The result is true if and only if the argument is not null and is
a String object that represents the same sequence of characters as this object.
public int compareTo(String anotherString)
Compares two strings lexicographically. ....
The result is a negative integer if this String object lexicographically precedes the argument string. The
result is a positive integer if this String object lexicographically follows the argument string. The result is
zero if the strings are equal; compareTo returns 0 exactly when the equals(Object) method would return
true. Mike -
Performance difference between page and scroll
Hi experts:
What is the technical difference between paging and scrolling, especially as pertains to database access and performance? The scenario would be a table result in a view where 200 results exist for a query. A scrollable table would show all results, while the paging table would show 10/20 per page. Is the database selection the same for both approaches? Or is the paging approach going to make more trips? If there are trips - how does the UI know how many pages should be presented? Is one or the other a better approach for data which is not existing in CRM system?
regards,
bill.If you look at the servlet translated from a JSP, you'll see these lines:
Object page = this;
pageContext = _jspxFactory.getPageContext(this, request, response,
null, true, 8192, true);
_jspx_page_context = pageContext;
application = pageContext.getServletContext();So page is simply an alias for this.
And PageContext is analogous to ServletContext but please notice, it's not the same or a replacement; application is the implicit reference to ServletContext and not pageContext. There is no equivalent of pageContext in servlets.
Please note that the page scope doesn't refer to the page object but to the pageContext. Therefore, what Manivel said above
page is used as a scope with in one jspisn't correct.
Edited by: nogoodatcoding on Sep 24, 2007 1:30 PM -
Difference between defun and Rule
Hi all,
Does anyone know the difference between <defun> and <Rule>? Can <defun> be used to generate a library of methods.. the only thing I think is you have to include the form with all these defun's to call any of those functions.
Would be nice if <defun> uses the same methodology as most programming languages... local variables are stored on stack, have higher precedence than global variables, their value is lost once the function returns, etc.... This is not the case in <Rule> where it can access the variables in the workflow which calls the rules! + localScope=false is the default value, etc.
Any other differences? (also validate if the differences I mentioned are correct).
Thanks,
Adi.Jayant,
The Implementation Rule is we write required SQL codes and Business rule is more Description about what is the Implementation rule is about. Lets say for an Example CASE WHEN COLUMN='ID' THEN 1 ELSE NULL END so the Business rule can write some thing like this - To check for column value if value is ID then populate as 1 else populate Null.
Hope this answers your question. If in case you worrying about or thinking should i need to write in Business rule i would say dont worry about it.
Let me know if you are looking for more information. -
REAL differences between STCMS and JMQ that can cause trouble?
hi *,
i wanted to start a collection of differences between STCMS and JMQ. before i was working with JMQ i had a very naive point of view and thought we would migrate to JMQ without having any difficulties besides administration process changes....
so far the bigest differences for me that i found until now are:
1) JMS properties are not allowed to start numerical like 1_firstJmsProp now they must be named like _1firstJmsProp
2) setting null values as property causes exceptions (i think it was JMSMessageFormatException or something like this..)
any other points you have found out till now?
regards chrisHi Chris,
what I also found out and not really forces me to use JMQ in production is, that in eManager the Queues of the Sun_JMQ - message server can not really be addressed! I have a test-project running that pulls regularly data into that queue running on the Sun_JMQ, but when I go to the Sun_JMQ - entry in eManager, I only see the queue, but the eManager says it is an empty queue - no "Min Sequence Number", "Max Sequence Number", ... not even the "Last Published Date/Time" is set. So, in production you would not be able to see how many data was already processed and when the last message was sent!
I assume this is related to the way data is gathered from the JMS-server and maybe Sun uses the SeeBeyond implementation here?!
Funny is, that when you stop the receiver of the Sun_JMQ - queue, you at least see how many data are waiting in the queue to be processed and you can also take a look at the messages waiting!
Edit: What I just saw is, that when you look at the "Logging"-tab of the Sun_JMQ-server in eManager you see the log-entries of the stcms-server in there (so from the other JMS-server)?!?!
Just my 2 cents...
Bernhard
Edited by: nocomm on Jul 31, 2008 10:55 PM -
Media Foundation Source or H264 / AC3 differences between Windows and Phone 8?
I've got a working Matroska (MKV) Media Foundation Source for a Windows Store app (PC x86). It will play several different matroska files that contain H264 encoded video and AC3-encoded audio. It even has seek support. I've written the app
as a HTML/typescript Universal app with the MF Source as a C++ dll.
The problem is that the same code will not work on Windows Phone 8. I can play videos that don't require the external MF Source (i.e. MP4 files and AVI files) just fine on both platforms through my app, but the same MKV videos that played on an x86
PC will not play on Windows Phone 8 (Lumia 920).
I looked at the specs for the Snapdragon processor and it should be able to support both H264 at 720p resolution and AC3 (2-channel only). So I don't know what else I need to do to get this to work on WP8. The audio I'm trying to play is actually
6-channel, so that made me wonder if it was failing because WP8 supports 2-channel max, but I would have thought the audio just wouldn't work and the video would play normally.
Does anyone have any suggestions?
*edit* - just to be more specific, I can parse the file and create the presentation descriptor without errors. But when I finish opening the file and call the event for that, nothing else happens. What is weird is that the javascript video player
never throws the "canplay" event, nor does it throw the "error" event.
Lee McPhersonThanks, not a bad suggestion to try.
On my Windows machine, I tried to get the MediaEncodingProfile via the createFromFileAsyc method. With a known file type, it outputs all properties of the video and audio streams (bitrate, etc). With an MKV file (container file with H264 video
and AC3 audio), I only get the type and subtype properties. Everything else is zero or null. This is because in my MFSource, I only set the type and subtype. This still allows the video to play on my windows machine. I assume the
built-in MFTransform for H264 video-to-uncompressed video parses the stream to get the relevant information. Likewise for audio.
On Windows Phone, when querying the file's MediaEncodingProfile, I get the same result. This is telling me that my MFSource will parse the file properly and set the subtypes for video and audio correctly. Everything else is still null or zero.
However, the file does not play. There is no returned event to the video element that it even *can* play.
Perhaps, I need to fill in the video and audio stream properties on the Windows Phone version. I really don't want to because that would mean having to parse some of the underlying video and audio streams themselves, not just parsing the container
information. (More work!) But this is what I mean when I ask about the differences between Windows and Windows Phone... perhaps the WP8.1 & Windows MFTransforms are different?
*EDIT* - I do get a JavaScript Console error that I didn't notice before: AUDIO/VIDEO: unknown MIME type. (VS error code: MEDIA12899)
Lee McPherson
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