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Posted to users@myfaces.apache.org by Mike Quentel <mq...@4dm-inc.com> on 2009/05/04 18:02:30 UTC
RE: dynamically populating a drop-down selection list with values from a database
Many thanks to Omar for his advice.now a related question:
Using javax.faces.model.SelectItem objects stored in an ArrayList is what
seems to work in terms of appearance, but I was hoping that each resulting
option tag would hold the same text for the value as well as the label. How
do I do this?
My JSF looks like:
<tr:selectOneListbox required="false" label="Users"
id="userRoleSelectOneListbox">
<f:selectItems value="#{userRoleBean.options}"/>
</tr:selectOneListbox>
My bean has:
protected ArrayList<SelectItem> options = null;
.
public ArrayList<SelectItem> getOptions() {
if (this.options == null) {
this.options = new ArrayList<SelectItem>();
for (int i = 0; i < userRoles.size(); i++) {
SelectItem si = new SelectItem();
String userName = userRoles.get(i).getUserName();
si.setLabel(new String(userName));
si.setValue(new String(userName));
this.options.add(si);
}
}
return options;
}
The resulting output in HTML looks like:
<option value="0">bob</option>
<option value="1">tom</option>
<option value="2">mary</option>
<option value="3">paul</option>
<option value="4">danielle</option>
I was hoping to have the value attributes match the labels, so that it looks
like:
<option value="bob">bob</option>
<option value="tom">tom</option>
<option value="mary">mary</option>
<option value="paul">paul</option>
<option value="danielle">danielle</option>
Otherwise, how am I supposed to get the right value to be submitted in the
form?
Sorry if this seems rather elementary as in "RTFM".if you happen to know a
tutorial that shows dynamically populating a selection list, then submitting
the values to update a database table, I'd be very interested. Seems like
every example is about having a simple statically created selection list.
Many thanks,
Mike Quentel
From: Omar E
Sent: 28 April 2009 19:46
To: MyFaces Discussion
Subject: Re: dynamically populating a drop-down selection list with values
from a database
In order to populate a selectOneListBox or selectOneChoice from a database
use:
<tr:selectOneListbox value="#{bean.aValue}" required="yes">
<f:selectItems value="#{myBacking.selectList}"
</tr:selectOneListbox>
selectList should be a collection of type SelectItem.
then your backing bean selectList should have a getter and a setter.
private List<SelectItem> selectList;
{
//TODO: instanciate the list and populate the list
}
public List<SelectItem> getSelectList() {
return selectList;
}
public void setSelectList(List<SelectItem> selectList) {
this.selectList = selectList;
}
the difference between selectOneListBox and selectOneChoice that
selectOneChoice is a drop down list and selectOneListBox is a list box. take
a look at the components guide demo.
http://www.irian.at/trinidad-demo/faces/components/selectOneChoice.jspx
http://www.irian.at/trinidad-demo/faces/components/selectOneListbox.jspx
--Omar
On Apr 28, 2009, at 7:01 PM, Mike Quentel wrote:
Please, would someone direct me to an example of populating a drop-down
selection list using values from a database table query? Most examples show
hard-coded values. I'm hoping to find an example (could be another library
than Trinidad; like Tomahawk or ADF) that includes the JSP and bean.
I'm using Trinidad. Not clear what the difference is between a
selectOneListbox and a selectOneChoice.
http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneListbox.h
tml
http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneChoice.ht
ml
They both seem the same.
If I use either one of the above, does my bean need to use
CoreSelectOneListBox in order to populate the drop-down list?
http://myfaces.apache.org/trinidad/trinidad-api/apidocs/org/apache/myfaces/t
rinidad/component/core/input/CoreSelectOneListbox.html
Where I'm most confused is the proper syntax in the JSP...just need a good
example.
Many thanks,
Mike Quentel
RE: dynamically populating a drop-down selection list with values from a database
Posted by Mike Quentel <mq...@4dm-inc.com>.
Many thanks to Mike K for the information; I was able to better understand
the Trinidad selectOneListBox and the methods needed for the bean.
What I found is that indeed, one need not have the selectOneListBox value
attributes match the labels of the selectOneListBox.
The way to bind the list box options to the bean is via the
javax.faces.event.ValueChangeEvent
To have this work with Trinidad selectOneListBox tag, the
valueChangeListener attribute must be set to the appropriate bean method for
updating the selected item. When the valueChangeListener attribute is set,
it is assumed that the ValueChangeEvent is passed to the method named in the
attribute. For example:
/////////////////////////////////
<tr:selectOneListbox required="false" label="Users"
id="userRoleSelectOneListbox"
valueChangeListener="#{userRoleBean.setSelectedUserListener}">
<f:selectItems value="#{userRoleBean.options}"/>
</tr:selectOneListbox>
/////////////////////////////////
userRoleBean.options is an ArrayList containing SelectItem objects.
The UserRoleBean.setSelectedUserListener method, along with the associated
property and setter, looks like this:
/////////////////////////////////
private String selectedUser;
...
public void setSelectedUserListener(ValueChangeEvent e) {
setSelectedUser((String)e.getNewValue());
}
public void setSelectedUser(String selectedUser) {
this.selectedUser = selectedUser;
}
/////////////////////////////////
The setSelectedRoleListener uses the ValueChangeEvent to pass the selected
item to the setter method for the bean property named selectedUser
Cheers,
Mike Quentel
-----Original Message-----
From: Mike K
Sent: 4 May 2009 12:16
To: MyFaces Discussion
Subject: Re: dynamically populating a drop-down selection list with values
from a database
In JSF, the idea is that you don't worry about how the select items
are stored. You use a converter to change it from your database
object to any arbitrary string representation (you pick), and then use
same converter algorithm to change it back from the string
representation to a database object. Some people use the primary key
as the string representation, but that often leaks information and
causes security issues.
I typically use the list index value. It does mean that you have to
preserve the ordered list between the initial display and the parsing
of the response, but that's not been an issue for me.
On Mon, May 4, 2009 at 12:02 PM, Mike Quentel <mq...@4dm-inc.com> wrote:
> Many thanks to Omar for his advice
now a related question:
>
>
>
> Using javax.faces.model.SelectItem objects stored in an ArrayList is what
> seems to work in terms of appearance, but I was hoping that each resulting
> option tag would hold the same text for the value as well as the label.
How
> do I do this?
>
>
>
> My JSF looks like:
>
>
>
> <tr:selectOneListbox required="false" label="Users"
> id="userRoleSelectOneListbox">
>
> <f:selectItems value="#{userRoleBean.options}"/>
>
> </tr:selectOneListbox>
>
>
>
> My bean has:
>
>
>
> protected ArrayList<SelectItem> options = null;
>
>
>
> public ArrayList<SelectItem> getOptions() {
>
> if (this.options == null) {
>
> this.options = new ArrayList<SelectItem>();
>
> for (int i = 0; i < userRoles.size(); i++) {
>
> SelectItem si = new SelectItem();
>
> String userName = userRoles.get(i).getUserName();
>
> si.setLabel(new String(userName));
>
> si.setValue(new String(userName));
>
> this.options.add(si);
>
> }
>
> }
>
> return options;
>
> }
>
>
>
> The resulting output in HTML looks like:
>
>
>
> <option value="0">bob</option>
>
>
>
> <option value="1">tom</option>
>
>
>
> <option value="2">mary</option>
>
>
>
> <option value="3">paul</option>
>
>
>
> <option value="4">danielle</option>
>
>
>
> I was hoping to have the value attributes match the labels, so that it
looks
> like:
>
>
>
> <option value="bob">bob</option>
>
>
>
> <option value="tom">tom</option>
>
>
>
> <option value="mary">mary</option>
>
>
>
> <option value="paul">paul</option>
>
>
>
> <option value="danielle">danielle</option>
>
>
>
> Otherwise, how am I supposed to get the right value to be submitted in the
> form?
>
>
>
> Sorry if this seems rather elementary as in RTFM
if you happen to know a
> tutorial that shows dynamically populating a selection list, then
submitting
> the values to update a database table, Id be very interested. Seems like
> every example is about having a simple statically created selection list.
>
>
>
> Many thanks,
>
>
>
> Mike Quentel
>
>
>
> From: Omar E
> Sent: 28 April 2009 19:46
> To: MyFaces Discussion
> Subject: Re: dynamically populating a drop-down selection list with values
> from a database
>
>
>
>
>
> In order to populate a selectOneListBox or selectOneChoice from a
> database use:
>
>
>
> <tr:selectOneListbox value="#{bean.aValue}" required="yes">
>
> <f:selectItems value="#{myBacking.selectList}"
>
> </tr:selectOneListbox>
>
>
>
> selectList should be a collection of type SelectItem.
>
>
>
> then your backing bean selectList should have a getter and a setter.
>
>
>
> private List<SelectItem> selectList;
>
> {
>
> //TODO: instanciate the list and populate the list
>
> }
>
>
>
> public List<SelectItem> getSelectList() {
>
> return selectList;
>
> }
>
>
>
> public void setSelectList(List<SelectItem> selectList) {
>
> this.selectList = selectList;
>
> }
>
>
>
> the difference between selectOneListBox and selectOneChoice that
> selectOneChoice is a drop down list and selectOneListBox is a list box.
take
> a look at the components guide demo.
>
>
>
> http://www.irian.at/trinidad-demo/faces/components/selectOneChoice.jspx
>
>
>
> http://www.irian.at/trinidad-demo/faces/components/selectOneListbox.jspx
>
>
>
> --Omar
>
>
>
>
>
> On Apr 28, 2009, at 7:01 PM, Mike Quentel wrote:
>
> Please, would someone direct me to an example of populating a drop-down
> selection list using values from a database table query? Most examples
show
> hard-coded values. I'm hoping to find an example (could be another
library
> than Trinidad; like Tomahawk or ADF) that includes the JSP and bean.
>
> I'm using Trinidad. Not clear what the difference is between a
> selectOneListbox and a selectOneChoice.
>
>
http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneListbox.h
> tml
>
>
http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneChoice.ht
> ml
>
> They both seem the same.
>
> If I use either one of the above, does my bean need to use
> CoreSelectOneListBox in order to populate the drop-down list?
>
>
http://myfaces.apache.org/trinidad/trinidad-api/apidocs/org/apache/myfaces/t
> rinidad/component/core/input/CoreSelectOneListbox.html
>
> Where I'm most confused is the proper syntax in the JSP...just need a good
> example.
>
> Many thanks,
>
> Mike Quentel
>
>
>
Re: dynamically populating a drop-down selection list with values
from a database
Posted by Mike Kienenberger <mk...@gmail.com>.
In JSF, the idea is that you don't worry about how the select items
are stored. You use a converter to change it from your database
object to any arbitrary string representation (you pick), and then use
same converter algorithm to change it back from the string
representation to a database object. Some people use the primary key
as the string representation, but that often leaks information and
causes security issues.
I typically use the list index value. It does mean that you have to
preserve the ordered list between the initial display and the parsing
of the response, but that's not been an issue for me.
On Mon, May 4, 2009 at 12:02 PM, Mike Quentel <mq...@4dm-inc.com> wrote:
> Many thanks to Omar for his advice…now a related question:
>
>
>
> Using javax.faces.model.SelectItem objects stored in an ArrayList is what
> seems to work in terms of appearance, but I was hoping that each resulting
> option tag would hold the same text for the value as well as the label. How
> do I do this?
>
>
>
> My JSF looks like:
>
>
>
> <tr:selectOneListbox required="false" label="Users"
> id="userRoleSelectOneListbox">
>
> <f:selectItems value="#{userRoleBean.options}"/>
>
> </tr:selectOneListbox>
>
>
>
> My bean has:
>
>
>
> protected ArrayList<SelectItem> options = null;
>
> …
>
> public ArrayList<SelectItem> getOptions() {
>
> if (this.options == null) {
>
> this.options = new ArrayList<SelectItem>();
>
> for (int i = 0; i < userRoles.size(); i++) {
>
> SelectItem si = new SelectItem();
>
> String userName = userRoles.get(i).getUserName();
>
> si.setLabel(new String(userName));
>
> si.setValue(new String(userName));
>
> this.options.add(si);
>
> }
>
> }
>
> return options;
>
> }
>
>
>
> The resulting output in HTML looks like:
>
>
>
> <option value="0">bob</option>
>
>
>
> <option value="1">tom</option>
>
>
>
> <option value="2">mary</option>
>
>
>
> <option value="3">paul</option>
>
>
>
> <option value="4">danielle</option>
>
>
>
> I was hoping to have the value attributes match the labels, so that it looks
> like:
>
>
>
> <option value="bob">bob</option>
>
>
>
> <option value="tom">tom</option>
>
>
>
> <option value="mary">mary</option>
>
>
>
> <option value="paul">paul</option>
>
>
>
> <option value="danielle">danielle</option>
>
>
>
> Otherwise, how am I supposed to get the right value to be submitted in the
> form?
>
>
>
> Sorry if this seems rather elementary as in “RTFM”…if you happen to know a
> tutorial that shows dynamically populating a selection list, then submitting
> the values to update a database table, I’d be very interested. Seems like
> every example is about having a simple statically created selection list.
>
>
>
> Many thanks,
>
>
>
> Mike Quentel
>
>
>
> From: Omar E
> Sent: 28 April 2009 19:46
> To: MyFaces Discussion
> Subject: Re: dynamically populating a drop-down selection list with values
> from a database
>
>
>
>
>
> In order to populate a selectOneListBox or selectOneChoice from a
> database use:
>
>
>
> <tr:selectOneListbox value="#{bean.aValue}" required="yes">
>
> <f:selectItems value="#{myBacking.selectList}"
>
> </tr:selectOneListbox>
>
>
>
> selectList should be a collection of type SelectItem.
>
>
>
> then your backing bean selectList should have a getter and a setter.
>
>
>
> private List<SelectItem> selectList;
>
> {
>
> //TODO: instanciate the list and populate the list
>
> }
>
>
>
> public List<SelectItem> getSelectList() {
>
> return selectList;
>
> }
>
>
>
> public void setSelectList(List<SelectItem> selectList) {
>
> this.selectList = selectList;
>
> }
>
>
>
> the difference between selectOneListBox and selectOneChoice that
> selectOneChoice is a drop down list and selectOneListBox is a list box. take
> a look at the components guide demo.
>
>
>
> http://www.irian.at/trinidad-demo/faces/components/selectOneChoice.jspx
>
>
>
> http://www.irian.at/trinidad-demo/faces/components/selectOneListbox.jspx
>
>
>
> --Omar
>
>
>
>
>
> On Apr 28, 2009, at 7:01 PM, Mike Quentel wrote:
>
> Please, would someone direct me to an example of populating a drop-down
> selection list using values from a database table query? Most examples show
> hard-coded values. I'm hoping to find an example (could be another library
> than Trinidad; like Tomahawk or ADF) that includes the JSP and bean.
>
> I'm using Trinidad. Not clear what the difference is between a
> selectOneListbox and a selectOneChoice.
>
> http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneListbox.h
> tml
>
> http://myfaces.apache.org/trinidad/trinidad-api/tagdoc/tr_selectOneChoice.ht
> ml
>
> They both seem the same.
>
> If I use either one of the above, does my bean need to use
> CoreSelectOneListBox in order to populate the drop-down list?
>
> http://myfaces.apache.org/trinidad/trinidad-api/apidocs/org/apache/myfaces/t
> rinidad/component/core/input/CoreSelectOneListbox.html
>
> Where I'm most confused is the proper syntax in the JSP...just need a good
> example.
>
> Many thanks,
>
> Mike Quentel
>
>
>