Valuechangelistener bug

Using jsf/adf bc components. jdev 10.1.3.2
This post is with reference to a documented bug:
Bug# 5060915 -- ADF FACES - CURSOR NOT GOING TO NEXT FIELD AFTER AUTO-SUBMIT TEXT FIELD has been created.
the topic can be found at : ADF Faces: af:input text with autosubmit and tabbing
I've read the topic posted on this and looked at the "work around", which involves using javascript to move to another field or component when the user changes a value and tabs out of the field. However, this doesn't cover the scenario where a user changes a value in an input text and then uses the mouse to click in another input text. If the first input text has a valuechangelistener associated with it and the user changes its value and clicks instead of tabs to the next field, you still have the problem of the cursor remaining in the initial input field instead of focus going to the input that was clicked on. I tried to use javascript (onclick) to move the focus to the field that should have focus, but this doesn't work. Any suggestions on how to overcome this problem?

Hi,
does this reproduce on IE only or Firefox as well? Development tested it and said that the issue referenced in the bug cannot be reproduced on any browser other than IE.
Frank

Similar Messages

BUG - JSF InputText boxes not populating properly

Okay,
Here's the situation:
I have an edit page (JSF Web) that allows the user to pick an item to edit from a SelectOneMenu tag. When they pick the item the page rerenders and shows the object associated with the selected item allowing the user to edit the object in various InputText controls.
First of all the ValueChangeListener event doesn't work for the SelectOneMenu tag - the event is not recognized in the backing bean (with or without immediate set, the event code is never accessed.) - and so I had to tie the change to the pressing of a command button.
Upon pressing the command button, in the action event, I find the object from the selected item. Now I want to set the input text boxes in the screen to the various values of the object. There are two ways to do this. I either set the value property of the bound (using the binding property) backing bean to the objects property - the code looks like this:
<h:inputText binding="#{EditCalendarBean.name}"
value="#{EditCalendarBean.name.value}"/>
This results in a fatal error that halts the OC4J.
Alternatively; I added various properties to the backing bean one for each property of the object and bound the object's properties to these and then bound the user interface's value properties to the bean properties. For example, imagine a user interface control InputText tag called "name" has it's value property bound to a property on the bean called Name which returns String. This configuration runs but the InputText control when the page is re-rendered (after the submit), is empty even though I've set the value property. However, if I add an OutputText control to the page and bind it's value property to the same String property of the bean, the outputText control correctly shows the value of the object.
The code looks like this:

<h:inputText id="name" binding="#{EditCalendarBean.name}"
value="#{EditCalendarBean.nameValue}"/>
// Code in the Backing bean:
// Find the Bean from the submitted id from the SelectMenuTag.
CalendarData data = manager.getCalendarById(calendarID) ;
// Set value of the UITextInput components on the page.
this.getName().setValue(data.getName());
this.getDescription().setValue(this.getDescription());
// This results in a fatal error that halts the OC4J
// Method 2: declare two String properties on the bean and set them
// Then, in the page use the Value property of the InputText control.
// This runs but doesn't populate the controls. It does populate them if
// the contols are OutputText controls though!!!
this.setNameValue(data.getName());
this.setDescriptionValue(data.getDescription());
Best regards,
Nigel

Yes - this really is a bug. Any changes to make to the selectItems tag through the properties dialog rewrites the tag source code to seperate the selectOne tag and the selectItems tag. For example, before you use the dialog, you tag code could look like this:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1">
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
</h:selectOneMenu>
After the use of the dialog the code will be rewritten as:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
Notice, the tags are now seperated instead of the selectItems tag being encased in the selectOneMenu tag.

BUG JSF Select Item not binding properly

Dear Oracle,
I'm running JDeveloper 10g version 10.1.3.0.3.3412 early access 1. If you create a HTMLMenu1 select list in a JSF Page and use the properties dialog to bind the values to a backing bean, the binding get's lost and the page doesn't call the value binding. What's more, if you try to rebind the values using the dialog, JDeveloper repeatedly inserts a new SelectItems tag for the menu.
For example, if you create the SelectMenu1 and then use the dialog to bind the selectItems to a backing bean property, you will end up with code something like this:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1"
valueChangeListener="#{backing_showFactory.selectFactoryEvent}"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems1}"
id="selectItems1"/>
Now, click on the newly created menu item in the design window of the JSP editor and bring up the properties dialog. You will see that the value binding is blank. If you reenter the value binding information, JDeveloper creates a new tag so you end up with the following:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1"
valueChangeListener="#{backing_showFactory.selectFactoryEvent}"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems1}"
id="selectItems1"/>
Each time you repeat the process, JDeveloper creates another tag:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1"
valueChangeListener="#{backing_showFactory.selectFactoryEvent}"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems3}"
id="selectItems3"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems1}"
id="selectItems1"/>
Either way, if you clean up the JSF page with the spurious tags, the value binding (in the example above backing_showFactory.allFactories), is never called.

Yes - this really is a bug. Any changes to make to the selectItems tag through the properties dialog rewrites the tag source code to seperate the selectOne tag and the selectItems tag. For example, before you use the dialog, you tag code could look like this:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1">
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
</h:selectOneMenu>
After the use of the dialog the code will be rewritten as:
<h:selectOneMenu binding="#{backing_showFactory.selectOneMenu1}"
id="selectOneMenu1"/>
<f:selectItems value="#{backing_showFactory.allFactories}"
binding="#{backing_showFactory.selectItems2}"
id="selectItems2"/>
Notice, the tags are now seperated instead of the selectItems tag being encased in the selectOneMenu tag.

JSF1.0. valueChangeListener has no effect for inputHidden

inputHidden has valueChangeListener, but it looks like it has no effect.
For example:
<h:inputHidden valueChangeListener="#{GetNameBean.callMe}" id="userName" />
if I replace inputHidden with inputText, the listener is been fired. Is it a bug or what? The same code works in the jsf-ri1.0 beta.
P.S. the same problem in case of using <f:valueChangeListener>

I have cut the previous text off before posting. This is a full version of the page where only inputText is replaced with inputHidden. Such code does not work.
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>
<f:loadBundle basename="demo.bundle.Messages" var="Message"/>
<HTML>
<HEAD> <title>Input Name Page</title> </HEAD>
<body bgcolor="white">
<f:view>
    <h1><h:outputText value="#{Message.inputname_header}"/></h1>
    <h:messages style="color: red"/>
    <h:form id="helloForm" >
    <h:outputText value="#{Message.prompt}"/>
    <h:inputHidden valueChangeListener="#{GetNameBean.callMe}" id="userName" value="#{GetNameBean.userName}" required="true">
       <f:validateLength minimum="2" maximum="20"/>
     </h:inputHidden>
     <h:commandButton id="submit" action="sayhello" value="Say Hello" />
    </h:form>
   </f:view>
</body>
</HTML> demo.GetNameBean:
package demo;
import javax.faces.event.ValueChangeEvent;
import javax.faces.event.AbortProcessingException;
public class GetNameBean {
     String userName;
     public String getUserName() {
          return userName;
     public void setUserName(String name) {
          userName = name;
     public void callMe(ValueChangeEvent event)
     throws AbortProcessingException {
          userName="Duke";

Multiple calls to ValueChangeListener through only one change event...

Hi All,
I created a datatable that contains a set of records, each record consists of checkbox , name and account ...
I registered a ValueChangeListener for the checkbox...when I press any of the checkboxes...the method is called for all the checkboxes in the datatable...what if I want only that checked checkbox to be selected...
A appreciate any help...
Thanks...
<h:dataTable value="#{CustomersDB.subCustomers}" var="customers" border="1" id="custtable">

<h:column>
<h:selectBooleanCheckbox value="false" valueChangeListener="#{Customer.addUserToList}"/>
</h:column>
<h:column>
<h:outputText value="#{customers.name}"/>
</h:column>
<h:column>
<h:outputText value="#{customers.account}"/>
</h:column>
</h:dataTable>

How very weird. If I step through the change logic (into the JavaFX library source), for each r.setName call line-by-line using the Intellij Idea debugger, then the behavior is as expected and all changes are reported. If I just run the program without stepping (either inside or outside the debugger), then not all changes are reported (as in your question). So it seems that stepping through in the debugger somehow triggers the evaluation of some expression which lazily resolves the property change correctly. Schrödinger's cat has been irradiated
I glanced through the JavaFX 8u40 source and can't work out what is going on.
I ran my tests on OS X 10.9 and Idea 14.1.
Log a bug report:
https://javafx-jira.kenai.com/

Valuechangelistener in oracle jdeveloper 10.1.3.1

Hi,,
I am using jdeveloper 10.1.3.1
Before this im using jdeveloper 10.1.3.0,,, from this version, i build my own valuechangelistener for a dropdownlist to filter another dropdownlist,,,
When i'm migrating my application to 10.1.3.1, my valuechangelistener not functioning as expected in 10.1.3.0 version...
it seems on 10.1.3.1 the valuechangelistener refresh the page, compare to valuechangelistener in 10.1.3.0 it doesn't refresh it..
So it's a bug,,,,
I need a solution for this.. pls help me,,It's an urgent case... needed to settle this...
Thanks...

Hi,
Thanks for immediate reply.
The strange behavior of valuechangelistener is, it works in jdeveloper 10.1.3.0 where the partial page request done well...
but in jdeveloper 10.1.3.1, the partial page doesnt work, my page totally refresh a.k.a been submitted....
this is my jsp code:
<af:panelForm labelWidth="29%" fieldWidth="71%" width="100%">
<af:selectOneChoice autoSubmit="true" id="filters"
valueChangeListener="#{listKodBandarPekanMukim.madeChanges}"
label="Daerah :" showRequired="true"
binding="#{backingSpoc.daerahHasil}" valuePassThru="true">
<f:selectItems value="#{listKodDaerah.list}"/>
</af:selectOneChoice>
<af:selectOneChoice label="Bandar/Pekan/Mukim :"
value="#{kaunterHasil.bandarPekanmukim}"
partialTriggers="filters" showRequired="true"
binding="#{listKodBandarPekanMukim.kodBandarPekanMukimCommon}">
<f:selectItems value="#{listKodBandarPekanMukim.list}"/>
</af:selectOneChoice>
</af:panelForm>
this is my coding part in backing bean:
public void madeChanges(ValueChangeEvent valueChangeEvent){
ManageCRUD manager = new ManageCRUD();
Object obj = valueChangeEvent.getNewValue();
Object test = valueChangeEvent.getSource();
if(test!=null){
CoreSelectOneChoice csoc = (CoreSelectOneChoice) test;
csoc.getChildren();
if(obj!=null){
String a = new String();
if(!obj.getClass().isInstance(a)){
KodDaerah obj1 = (KodDaerah)valueChangeEvent.getNewValue();
Expression exp = new ExpressionBuilder();
getList(manager.ReadByExpression(KodBandarpekanmukim.class,
exp.getField("KOD_DAERAH").equal(obj1.getKod().toCharArray())));
if(kodBandarPekanMukimCommon!=null)
kodBandarPekanMukimCommon.setValue(null);
}

Index with "or" clause (BUG still exists?)

The change log for 2.3.10 mentions "Fixed a bug that caused incorrect query plans to be generated for predicates that used the "or" operator in conjunction with indexes [#15328]."
But looks like the Bug still exists.
I am listing the steps to-repro. Let me know if i have missed something (or if the bug needs to be fixed)
DATA
dbxml> openContainer test.dbxml
dbxml> getDocuments
2 documents found
dbxml> print
<node><value>a</value></node>
<node><value>b</value></node>
INDEX (just one string equality index on node "value")
dbxml> listIndexes
Index: unique-node-metadata-equality-string for node {http://www.sleepycat.com/2002/dbxml}:name
Index: node-element-equality-string for node {}:value
2 indexes found.
QUERY
setVerbose 2 2
preload test.dbxml
query 'let $temp := fn:compare("test", "test") = 0
let $results := for $i in collection("test.dbxml")
where ($temp or $i/node[value = ("a")])
return $i
return <out>{$temp}{$results}</out>'
When $temp is true i expected the result set to contain both the records, but that was not the case with the index. It works well when there is no index!
Result WITH INDEX
dbxml> print
<out>true<node><value>a</value></node></out>
Result WITHOUT INDEX
dbxml> print
<out>true<node><value>a</value></node><node><value>b</value></node></out>

Hi Vijay,
This is a completely different bug, relating to predicate expressions that do not examine nodes. Please try the following patch, to see if it fixes this bug for you:
--- dbxml-2.3.10-original/dbxml/src/dbxml/optimizer/QueryPlanGenerator.cpp     2007-04-18 10:05:24.000000000 +0100
+++ dbxml-2.3.10/dbxml/src/dbxml/optimizer/QueryPlanGenerator.cpp     2007-08-08 11:32:10.000000000 +0100
@@ -1566,11 +1572,12 @@
     else if(name == Or::name) {
          UnionQP *unionOp = new (&memMgr_) UnionQP(&memMgr_);
+          result.operation = unionOp;
          for(VectorOfASTNodes::iterator i = args.begin(); i != args.end(); ++i) {
               PathResult ret = generate(*i, ids);
               unionOp->addArg(ret.operation);
+               if(ret.operation == 0) result.operation = 0;
-          result.operation = unionOp;
     // These operators use the presence of the node arguments, not their valueJohn

Bug report follow-up

is there a way to follow-up on a bug report that i submitted? i have the bug number, but would like to see if the report was understood, filled out properly and determine the status of the bug report.
thanks,
doug

They comment on bugs if actions were taken. Otherwise - don't expect any feedback.

Solaris8 and 9 (possibly 7) /dev/poll driver bug report.

Hello,
I'd like to report a bug in the solaris 8 and 9 /dev/poll driver (poll(7d)).
As i do not have a support account with sun or anything like that, there
seems to be no other way to do that here (which is of course a very sad
thing).
Bug details:
The /dev/poll device provides an ioctl-request (DP_ISPOLLED) for checking
if a particular filedescriptor is currently in the set of monitored
filedescriptors for that particular /dev/poll fd set (open /dev/poll fd).
A quote from the documentation of the poll(7d) manual page taken from
Solaris9:
"DP_ISPOLLED ioctl allows you to query if a file descriptor is already in
the monitored set represented by fd. The fd field of the pollfd structure
indicates the file descriptor of interest. The DP_ISPOLLED ioctl returns 1
if the file descriptor is in the set. The events field contains the
currently polled events. The revents field contains 0. The ioctl returns 0
if the file descriptor is not in the set. The pollfd structure pointed by
pfd is not modified. The ioctl returns a -1 if the call fails."
It says that when you query for an filedescriptor which is currently being
monitored in the set, that it would return 1, and change the events field of
the pollfd structure to the events it's currently monitoring that fd for.
The revents field would be set to zero.
However the only thing which actually happens here, is that FD_ISPOLLED
returns 1 when the fd is in the set and 0 if not. When the fd is in the
set, when FD_ISPOLLED returns 1, the events field remains unmodified, but
the revents field gets changed.
A small sample code to illustrate:
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/devpoll.h>
main() {
struct pollfd a;
int dp_fd = open("/dev/poll", O_WRONLY);
a.fd = 0; /* stdin */
a.events = POLLIN; /* we monitor for readability, POLLIN=1 */
a.revents = 0;
write(dp_fd, &a, sizeof(a));
a.fd = 0;
a.events = 34; /* filled in with bogus number to show malfunctioning */
a.revents = 0;
printf("DP_ISPOLLED returns: %d\n", ioctl(dp_fd, DP_ISPOLLED, &a));
printf("a.fd=%d, a.events=%hd, a.revents=%hd\n", a.fd, a.events,
a.revents);
According to the documentation of /dev/poll and namely DP_ISPOLLED this
program is supposed to print the following:
DP_ISPOLLED returns: 1
a.fd=0, a.events=1, a.revents=0
However it prints the following:
DP_ISPOLLED returns: 1
a.fd=0, a.events=34, a.revents=1
You can take any number instead of '34' and it will simply remain untouched
after the DP_ISPOLLED ioctl-request.
I hope it's clear now that the solaris8 and solaris9 (and probably solaris7
with /dev/poll patch too) DP_ISPOLLED implementation is broken.
This bug is also easily illustrated by looking at the solaris8 kernel sourcecode:
<snippet osnet_volume/usr/src/uts/common/io/devpoll.c:dpioctl()>
case DP_ISPOLLED:
pollfd_t pollfd;
polldat_t *pdp;
if (pollfd.fd < 0) {
mutex_exit(&pcp->pc_lock);
break;
pdp = pcache_lookup_fd(pcp, pollfd.fd);
if ((pdp != NULL) && (pdp->pd_fd == pollfd.fd) &&
(pdp->pd_fp != NULL)) {
pollfd.revents = pdp->pd_events;
if (copyout(&pollfd, (caddr_t)arg,
sizeof(pollfd_t))) {
mutex_exit(&pcp->pc_lock);
DP_REFRELE(dpep);
return (set_errno(EFAULT));
*rvalp = 1;
</snippet>
its' clearly visible that the code writes the current monitored events to
the revents field:
'pollfd.revents = pdp->pd_events;'
and that it doesnt set revents to zero.
It's funny to see that this has been like this since Solaris8 (possibly 7). That means nobody ever used DP_ISPOLLED that way or people were simply to lazy to file a bug report.
Another funny thing related to this. is that Hewlett-Packard did seem to know about this. Since HP-UX11i version 1.6 they also support /dev/poll. From their manual page i ll quote some sentences from their WARNING session:
"The ioctl(DP_ISPOLLED) system call also returns its result in the revents member of the pollfd structure, in order to be compatible with the implementation of the /dev/poll driver by some other vendors."
Hopefully this will get fixed.
I also like to reexpress my very negative feelings towards the fact that you're not able to file bug reports when you do not have a support contract. Ridiculous.
Thanks,
bighawk

Have I mentioned how much i love my playbook now Great job on os 2.0

[bdb bug]repeatly open and close db may cause memory leak

my test code is very simple :
char *filename = "xxx.db";
char *dbname = "xxx";
for( ; ;)
DB *dbp;
DB_TXN *txnp;
db_create(&dbp,dbenvp, 0);
dbenvp->txn_begin(dbenvp, NULL, &txnp, 0);
ret = dbp->open(dbp, txnp, filename, dbname, DB_BTREE, DB_CREATE, 0);
if(ret != 0)
printf("failed to open db:%s\n",db_strerror(ret));
return 0;
txnp->commit(txnp, 0);
dbp->close(dbp, DB_NOSYNC);
I try to run my test program for a long time opening and closing db repeatly, then use the PS command and find the RSS is increasing slowly:
ps -va
PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND
1986 pts/0 S 0:00 466 588 4999 980 0.3 -bash
2615 pts/0 R 0:01 588 2 5141 2500 0.9 ./test
after a few minutes：
ps -va
PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND
1986 pts/0 S 0:00 473 588 4999 976 0.3 -bash
2615 pts/0 R 30:02 689 2 156561 117892 46.2 ./test
I had read bdb's source code before, so i tried to debug it for about a week and found something like a bug:
If open a db with both filename and dbname, bdb will open a db handle for master db and a db handle for subdb,
both of the two handle will get an fileid by a internal api called __dbreg_get_id, however, just the subdb's id will be
return to bdb's log region by calling __dbreg_pop_id. It leads to a id leak if I tried to open and close the db
repeatly, as a result， __dbreg_add_dbentry will call realloc repeatly to enlarge the dbentry area, this seens to be
the reason for RSS increasing.
Is it not a BUG?
sorry for my pool english :)
Edited by: user9222236 on 2010-2-25 下午10:38

I have tested my program using Oracle Berkeley DB release 4.8.26 and 4.7.25 in redhat 9.0 (Kernel 2.4.20-8smp on an i686) and AIX Version 5.
The problem is easy to be reproduced by calling the open method of db handle with both filename and dbname being specified and calling the close method.
My program is very simple:
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include "db.h"
int main(int argc, char * argv[])
int ret, count;
DB_ENV *dbenvp;
char * filename = "test.dbf";
char * dbname = "test";
db_env_create(&dbenvp, 0);
dbenvp->open(dbenvp, "/home/bdb/code/test/env",DB_CREATE|DB_INIT_LOCK|DB_INIT_LOG|DB_INIT_TXN|DB_INIT_MPOOL, 0);
for(count = 0 ; count < 10000000 ; count++)
DB *dbp;
DB_TXN *txnp;
db_create(&dbp,dbenvp, 0);
dbenvp->txn_begin(dbenvp, NULL, &txnp, 0);
ret = dbp->open(dbp, txnp, filename, dbname, DB_BTREE, DB_CREATE, 0);
if(ret != 0)
printf("failed to open db:%s\n",db_strerror(ret));
return 0;
txnp->commit(txnp, 0);
dbp->close(dbp, DB_NOSYNC);
dbenvp->close(dbenvp, 0);
return 0;
DB_CONFIG is like below:
set_cachesize 0 20000 0
set_flags db_auto_commit
set_flags db_txn_nosync
set_flags db_log_inmemory
set_lk_detect db_lock_minlocks
Edited by: user9222236 on 2010-2-28 下午5:42
Edited by: user9222236 on 2010-2-28 下午5:45

Multiple return values (Bug-ID 4222792)

I had exactly the same request for the same 3 reasons: strong type safety and code correctness verification at compile-time, code readability and ease of mantenance, performance.
Here is what Sun replied to me:
Autoboxing and varargs are provided as part of
JSRs 14 and 201
http://jcp.org/en/jsr/detail?id=14
http://jcp.org/en/jsr/detail?id=201
See also:
http://forum.java.sun.com/forum.jsp?forum=316
http://developer.java.sun.com/developer/earlyAccess/adding_generics/index.html
Multiple return values is covered by Bug-ID 4222792
Typically this is done by returning an array.
http://developer.java.sun.com/developer/bugParade/bugs/4222792.html
That's exactly the problem: we dynamically create instances of array objects that would better fit well within the operand stack without stressing the garbage collector with temporary Array object instances (and with their backing store: 2 separate allocations that need to be recycled when it is clearly a pollution that the operand stack would clean up more efficiently)
If you would like to engage in a discussion with the Java Language developers, the Generics forum would be a better place:
http://forum.java.sun.com/forum.jsp?forum=316
I know that (my report was already refering to the JSR for language extension) Generics is not what I was refering to (even if a generic could handle multiple return values, it would still be an allocated Object
instance to pack them, i.e. just less convenient than using a static class for type safety.
The most common case of multiple return values involve values that have known static datatypes and that should be checked with strong typesafety.
The simple case that involves returning two ints then will require at least two object instances and will not solve the garbage collection overhead.
Using a array of variable objects is exactly similar, except that it requires two instances for the components and one instance for the generic array container. Using extra method parameters with Integer, Byte, ... boxing objects is more efficient, but for now the only practical solution (which causes the least pollution in the VM allocator and garbage collector) is to use a custom class to store the return values in a single instance.
This is not natural, and needlessly complexifies many interfaces.
So to avoid this pollution, some solutions are used such as packing two ints into a long and returning a long, depacking the long after return (not quite clean but still much faster at run-time for methods that need to be used with high frequencies within the application. In some case, the only way to cut down the overhead is to inline methods within the caller code, and this does not help code maintenance by splitting the implementation into small methods (something that C++ can do very easily, both because it supports native types parameters by reference, and because it also supports inline methods).
Finally, suppose we don't want to use tricky code, difficult to maintain, then we'll have to use boxing Object types to allow passing arguments by reference. Shamely boxed native types cannot be allocated on the operand stack as local variables, so we need to instanciate these local variables before call, and we loose the capacity to track the cases where these local variables are not really initialized by an effective call to the method that will assign them. This does not help debugging, and is against the concept of a strongly typed language like Java should be:
Java makes lots of efforts to track uninitialized variables, but has no way to determine if an already instanciated Object instance refered in a local variable has effectively received an effective assignment because only the instanciation is kept. A typical code will then need to be written like this:
Integer a = null;
Integer b = null;
if (some condition) {
//call.method(a, b, 0, 1, "dummy input arg");
// the method is supposed to have assigned a value to a and b,
// but can't if a and b have not been instanciated, so we perform:
call.method(a = new Integer(), b = new Integer(), 0, 1, "dummy input
arg");
// we must suppose that the method has modified (not initialized!)
the value
// of a and b instances.
now.use(a.value(), b.value())
// are we sure here that a and b have received a value????
// the code may be detected at run-time (a null exception)
// or completely undetected (the method() above was called but it
// forgot to assign a value to its referenced objects a and b, in which
// case we are calling in fact: now.use(0, 0); with the default values
// or a and b, assigned when they were instanciated)
Very tricky... Hard to debug. It would be much simpler if we just used:
int a;
int b;
if (some condition) {
(a, b) = call.method(0, 1, "dummy input arg");
now.use(a, b);
The compiler would immediately detect the case where a and b are in fact not always initialized (possible use bere initialization), and the first invoked call.method() would not have to check if its arguments are not null, it would not compile if it forgets to return two values in some code path...
There's no need to provide extra boxing objects in the source as well as at run-time, and there's no stress added to the VM allocator or garbage collector simply because return values are only allocated on the perand stack by the caller, directly instanciated within the callee which MUST (checked at compile-time) create such instances by using the return statement to instanciate them, and the caller now just needs to use directly the variables which were referenced before call (here a and b). Clean and mean. And it allows strong typechecking as well (so this is a real help for programmers.
Note that the signature of the method() above is:
class call {
(int, int) method(int, int, String) { ... }
id est:
class "call", member name "method", member type "(IILjava.lang.string;)II"
This last signature means that the method can only be called by returning the value into a pair of variables of type int, or using the return value as a pair of actual arguments for another method call such as:
call.method(call.method("dummy input arg"), "other dummy input arg")
This is strongly typed and convenient to write and debug and very efficient at run-time...

Can anyone give me some real-world examples where
multiple return values aren't better captured in a
class that logically groups those values? I can of
course give hundreds of examples for why it's better
to capture method arguments as multiple values instead
of as one "logical object", but whenever I've hankered
for multiple return values, I end up rethinking my
strategy and rewriting my code to be better Object
Oriented.I'd personally say you're usually right. There's almost always a O-O way of avoiding the situation.
Sometimes though, you really do just want to return "two ints" from a function. There's no logical object you can think of to put them in. So you end up polluting the namespace:
public class MyUsefulClass {
public TwoInts calculateSomething(int a, int b, int c) {
public static class TwoInts {
    //now, do I use two public int fields here, making it
    //in essence a struct?
   //or do I make my two ints private & final, which
   //requires a constructor & two getters?
//and while I'm at it, is it worth implementing
//equals(), how about hashCode()? clone()?
//readResolve() ?
}The answer to most of the questions for something as simple as "TwoInts" is usually "no: its not worth implementing those methods", but I still have to think about them.
More to the point, the TwoInts class looks so ugly polluting the top level namespace like that, MyUsefulClass.TwoInts is public, that I don't think I've ever actually created that class. I always find some way to avoid it, even if the workaround is just as ugly.
For myself, I'd like to see some simple pass-by-value "Tuple" type. My fear is it'd be abused as a way for lazy programmers to avoid creating objects when they should have a logical type for readability & maintainability.
Anyone who has maintained code where someone has passed in all their arguments as (mutable!) Maps, Collections and/or Arrays and "returned" values by mutating those structures knows what a nightmare it can be. Which I suppose is an argument that cuts both ways: on the one hand you can say: "why add Tuples which would be another easy thing to abuse", on the other: "why not add Tuples, given Arrays and the Collections framework already allow bad programmers to produce unmainable mush. One more feature isn't going to make a difference either way".
Ho hum.

Extensions like Ghostery, WOT or AdBlock stop working after two or three times. Restarting the webpage in a new tab the extensions will work again for several times and then stop again. Has anybody an explanation or a workaround for this bug in Safari 5?

Extensions like Ghostery, WOT or AdBlock stop working after two or three times. Restarting the webpage in a new tab the extensions will work again for several times and then stop again. Has anybody an explanation or a workaround for this bug in Safari 5?

Remove the extensions, redownload Safari, reload the extensions.
http://www.apple.com/safari/download/
And if you really want a better experience, use Firefox, tons more choices and possibilities there.
Firefox's "NoScript" will block the Trojan going around on websites. Best web security you can get.
https://addons.mozilla.org/en-US/firefox/addon/noscript/
Ghostery, Ad Block Plus and thousands of add-ons more have originated on Firefox.

Bug? My events on the iPad iCal app aren't shown in the year view if they are more than two years in the future.

My events on the iPad iCal app aren't shown in the year view if they are more than two years in the future even though I can see them on the month, week and day view. Any suggestions on how to fix it? I've tried it all. I called the apple support and they checked on their iPads. They all did the same and they couldn't help me. They suggested trying this way. I'd like to be able to plan a few years ahead and the year view would make thing so easy!
Is this a bug?

Go to the Home screen and double click the Home button. That will reveal the row of recently used apps at the bottom of the screen. Tap and hold on the app in question until it wiggles and displays a minus sign. Tap the minus sign to actually quit the app. Then tap anywhere on the screen above that bottom row to return the screen to normal. Then restart the app and see if it works normally.
Then reboot your iPad. Press and hold the Home and Sleep buttons simultaneously ignoring the red slider until the Apple logo appears. Let go of the buttons and let the iPad restart. See if that fixes your problem.

HT4528 My IPhone Bugged out/It is currently in the reset mode. I need to exchange all of my contacts from my Yahoo acct. to my new IPHONE. Can you please help me?

Hello ,
I purchased my IPHONE about 2 months ago. I am visiting family in DE & this tuesday it starting to go off & on by itself. Then the icons looked like they were floating . Then I could not call or text . The SIRI device would not work. Then it would shut down then the apple icon would reappear. I took it to a verizon dealer in Rehoboth DE & they said it BUGGED OUT/It is in a RESTORE MODE. It will not turn on. We could not transfer anny of my pics or contacts. I never even had a chance to back up the memory on ITUNES.
The tech @ Verizon said to contact APPLE to trouble shoot and try and transfer the contacts from my yahoo acct.
Can you please help?
Gina

set up your yahoo account in mail, contacts, calendars as an Exchange Account and you should be able to get your contacts from Yahoo from there.

ICal bug!

Didn't know where to post it so I decided to post it here. Not a major bug, but a bug nevertheless. Maybe someone here wants to check it out on their iCal so I get a sense if it is touching just me or anyone else.
Follow all steps:
- open iCal in weekly view.
- click on a day differen than "today".
- click on "today" on the upper left side (where "today" is written ).
- click on the red dot to "close the app" without really closing it.
- reopen iCal by clicking on the icon.
Now you should have the today button greyed out, no matter which day you choose. The only way to have it back is to close and reopen iCal.
No data loss, nothing... Just a little bug I found in iCal.
I run Mac OSX 10.5.4 on a MacBook Pro 17" no plugins, nothing installed. Software is in italian.
Anyway: others get the same result? (just checked it again to be really sure it is indeed not working, and it's not..)

Has a real solution to this bug been found yet? It has been on going for me and has become annoying. The only way to get the "today" button and the search feature to work, is to quit iCal and start it again.
Very annoying.

Valuechangelistener bug

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