Rendering Querydata in nested Custom-Tags
Hi all
I have built two custom-tags to render the results of a query
in a table (a bit like the display-tag-library or the datatable-tag
of JSF). the parent tag takes the query as attributes as well as
some other things like records per page.
the child-tag defines a single column. the developer can
define a query-column-name in an attribute as well as the label and
so on.
the typical code looks like this and this works fine:
<tags:dataTable collection="#AddressQuery#"
basePath="#link.list#">
<tags:dataTableColumn column="id" label=""
selection="true" />
<tags:dataTableColumn column="name" label="Name"
sortable="true" />
<tags:dataTableColumn column="street" label="Strasse"
sortable="true" />
<tags:dataTableColumn column="houseNumber"
label="Hausnummer" sortable="true" />
<tags:dataTableColumn column="isEnabled" label="Aktiv"
sortable="false" />
</tags:dataTable>
Now, I'd like to allow the developer to write custom code to
generate the content of a table column. For example show the value
of a bit-field with icons:
<tags:dataTableColumn label="my bit-column">
<cfif #columnname# gt 0>[display image
"active"]<cfelse>display image "inactive"</cfif>
</tags:dataTableColumn>
Unfortunately, this throws an error because the variable of
the querycolumnname can't be resolved when the tag-content is
executed (the query-loop is done when the parent's end-tag is
processed).
Can I prevent CF to execute the tag-content, but instead save
the code of the developer and execute it later when processing the
endtag of the parent?
If not can I solve this problem otherwise?
thanks
stefan
Hi Jesse.
I'm also working on something very similar to the tab pane you are talking about. Mine was inspired by the CoreJSF book (I used some of the downloadable pre-release chapters). Great book. It's at www.corejsf.com
The basic idea behind theirs (and mine) is that the tab pane widget maintains a collection of tabs as a property. In the tag handler class you can specify the tabs themselves as either child components or facets (they used f:selectItem and f:selectItems, along with facets). I liked the f:selectItems the best.
All of the rendering is done in the renderer class. The book has examples of how to include additional jsp content specified as a fragment.
I would really suggest having a look at the book.
Regards,
Dave Haas
Similar Messages
-
Hi,
How can I use nested custom tags in jsp?Note that not all custom tags will work like this. The tag must be designed to work this way. Some tags will not accept a body, others will accept a body, but will not process it through the JSP compiler, rather handling it as text/html.
Have you tried nesting them and you're not getting the expected results? Have you written these tags yourself and they're not working? -
Hello,
I have a custom tag that I've written that has some
attributes. I want to nest that tag inside of itself, and access
the attibutes of the parent tag. However, when I try to access the
parent tag's data from the child all I get is the child tag's data!
If there are two of the same custom tags in the context stack, is
it possible to access one from the other? Thanks for your help.
Tim> I can't use the
> CALLER scope, as that references the page that called
the first custom tag, no
> matter how deeply nested I am.
I think you should test the advice, before you make
assertions like this.
The CALLER scope refers to the variables scope of the
template that called
the currently executing custom tag. If your calling stack is
like this:
index.cfm
customTagA.cfm
customTagB.cfm
Then the situation is this:
1) In index.cfm: no caller scope.
2) In customTagA.cfm: caller scope references index.cfm's
variables scope.
3) custoTagB.cfm: caller scope references customTagA.cfm's
variables scope
(NOT index.cfm's one).
Similarly, if your calling stack is like this:
index.cfm
customTag.cfm (*)
customTag.cfm
customTag.cfm
customTag.cfm
Then the caller scope in each customTag.cfm instance refers
to the
variables scope of the file above it. The only caller scope
that
references index.cfm's variables scope is the customTag
instance marked
with (*).
If I understand your requirement, this is what you want. This
is why I
suggested it.
Adam -
Custom tag with rendered attribute
Is it possible to create a custom tag that operates similar to a JSF tag with the rendered attribute? Wrapping output with c:if test="..." is not as nice as the JSF rendered option, but I don't want to use JSF for this particular project.
Edited by: black_lotus on Nov 23, 2007 12:13 PMTLD File, per your previous recommendation:
<attribute>
<name>disabled</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
<type>boolean</type>
</attribute>My Tag class (snippet):
public class ButtonTag extends TagSupport
private boolean disabled;
public ButtonTag() {}
public boolean isDisabled()
return disabled;
public void setDisabled(boolean b)
disabled = b;
}A sample of the jsp file invoking it:
<c:set var="result" value="${computedValue}"/>
<ltm:button disabled="${result}"/>Regardless of the value of result, ("true" or "false") it always passes false to the setDisabled method of the button tag class. -
I've got a custom tag thats fairly basic such as the following:
<my:page>
</my:page>Now when the PageTag class runs, I want to have it query a database and grab a list of items and print them out such as:
Item 1
Item 2
Item 3
However I want to be able to override the way it prints out a particular item, so if I do something like:
<my:page>
<my:override dbitem="Item 1" replaceTextWith="Item 4" />
</my:page>Then I want to get something like:
Item 4
Item 2
Item 3
In other words, it needs to stay in order. So what I need is control of the children rendering process so I can replace the database row with the overridden item. Now this is an over-simplified method of what I am trying to do, for instance the <my:override> tag will actually have to render HTML, it cannot just be invisible and call its parent (<my:page>) and set some flag to override, it has to be standalone as well.I figured out how to handle all this, If you have a similar issue, look up extending BodyTagSupport instead of TagSupport. BodyTagSupport gives you much more control over the design and presentation of your tags.
-
Rendering A JPEG image with a custom tag
Hi All,
I have dilema. I'm trying to rendering a jpeg in IE/FireFox with a custom tag that I developed. I'm able to access the bean and invoke the getter method to return the InputStream property. But what gets rendered is the byte code not the image. I've tried just about anything I could think off. If any body has an answer I would difinitely appreciate it.
Thanks,
Tony
Below is the jsp, tld, bean and tag.
********************************* image.jsp ****************************************
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ taglib uri="/WEB-INF/custom-chtml.tld" prefix="chtml" %>
<html>
<head>
<title>HTML Page</title>
</head>
<body bgcolor="#FFFFFF">
<chtml:img name="photo" property="file"/>
</body>
</html>
********************************* custom-chtml.tld **********************************
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.1</jspversion>
<shortname>chtml</shortname>
<tag>
<name>img</name>
<tagclass>com.struts.taglib.CustomImgTag</tagclass>
<bodycontent>empty</bodycontent>
<attribute>
<name>name</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>property</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
**************************** MemberPhotoBean.java ******************************
import java.io.InputStream;
* @author tony
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
public class MemberPhotoValue {
private String memberId;
private int fileSize;
private InputStream file;
public MemberPhotoValue() {
public MemberPhotoValue(String memberId, InputStream file) {
this.memberId = memberId;
this.file = file;
public MemberPhotoValue(String memberId,int fileSize,InputStream file) {
this.memberId = memberId;
this.fileSize = fileSize;
this.file = file;
public String getMemberId(){
return memberId;
public void setMemberId(String memberId) {
this.memberId = memberId;
public int getFileSize() {
return fileSize;
public void setFileSize(int fileSize) {
this.fileSize = fileSize;
public InputStream getFile(){
return file;
public void setFile(InputStream file) {
this.file = file;
*************************** CustomTagHandler.java ********************************
import java.io.*;
import javax.imageio.ImageIO;
import javax.servlet.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.awt.image.*;
import java.awt.*;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.*;
* JSP Tag Handler class
* @jsp.tag name = "CustomImg"
* display-name = "Name for CustomImg"
* description = "Description for CustomImg"
* body-content = "empty"
public class CustomImgTag implements Tag {
private PageContext pageContext;
private Tag parent;
private String property;
private String name;
private Class bean;
public int doStartTag() throws JspException {
return SKIP_BODY;
public int doEndTag() throws JspException {
try {
ServletResponse response = pageContext.getResponse();
// read in the image from the bean
InputStream stream = (InputStream) invokeBeanMethod();
BufferedImage image = ImageIO.read(stream); Image inImage = new ImageIcon(image).getImage();
Graphics2D g = image.createGraphics();
g.drawImage(inImage,null,null);
OutputStream out = response.getOutputStream();
// JPEG-encode the image
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();
} catch (IOException io) {
throw new JspException(io.getMessage());
return EVAL_PAGE;
public void release(){}
private InputStream invokeBeanMethod() throws JspException {
try {
Object bean = null;
if (null != pageContext.getAttribute(name)) {
bean = (Object) pageContext.getAttributename);
else if (null != pageContext.getSession().getAttribute(name)) {
bean = (Object) pageContext.getSession().getAttribute(name);
else if (null != pageContext.getRequest().getAttribute(name)) {
bean = (Object) pageContext.getRequest().getAttribute(name);
else {
throw new JspException("Bean : "+name+" is not found in any pe.");
Class[] parameters = null;
Object[] obj = null;
Method method = bean.getClass().getMethod("getFile",parameters);
return (InputStream) method.invoke(bean,obj);
} catch (NoSuchMethodException ne) {
throw new JspException("No getter method "+property+" for bean : "+bean);
} catch (IllegalAccessException ie) {
throw new JspException(ie.getMessage());
} catch (InvocationTargetException ie) {
throw new JspException(ie.toString());
public void setPageContext(PageContext pageContext) {
this.pageContext = pageContext;
public void setParent(Tag parent) {
this.parent = parent;
public Tag getParent() {
return parent;
public void setProperty(String property) {
this.property = property;
public void setName(String name) {
this.name = name;
**************************************************************************************If you have access to an image editing tool such as photoshop, I would advice you import the image into Phototshop and save it in a different format e.g, GIF format and re-import it into Final Cut Express HD. This could solve your rendering problem if all you need is to use a Still image.
Ayemenre -
Custom Tag output not being rendered in JSF
Hello,
I have the following for loop in a custom tag that I developed;
out.println("<ul>");
for (int i = 0; i < noOfDays; i++)
//out.println("<li><h:commandLink value=\"" +DateHelper.addDays(dtToday, i)+ "\" action=\"#{BookingBean.showAvailability}\"/></li>");
out.println("<li><a href=\"" +DateHelper.addDays(dtToday, i)+ "\">" DateHelper.addDays(dtToday, i) "</a></li>");
out.println("</ul>");
The issue I have is that the second line prints out fine whereas the first one (when uncommented) prints out the bullet points associated with a list but does not render the h:commandLink.
Any thoughts would be great.
Cheers,
RichHi,
You can not embade a JSF tag in your code as you did, try adding component as children to your custum tag
see this code as exemple : [HTMLDataTable.java|http://www.docjar.com/html/api/org/apache/myfaces/component/html/ext/HtmlDataTable.java.html] -
Custom Tag Attribute not correctly rendered
Hello,
I made a custom tag and I want the engine to parse dynamic scripts and evaluate them.
I call the tag like this :
<form:toolbaritem id="icon_cancelar" action="javascript:listingAction('<%= request.getContextPath() %>/logout.do');" icon="<%= request.getContextPath() %>/images/toolbar/Cancelar_32.gif"/>The icon and action attributes are declared in the tld like so :
<attribute>
<name>action</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>icon</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>However, the tag is not working with the evaluated expression, receiving "<%= request.getContextPath() %>" instead.
Any help would be very welcome :) thank you
EamerialGotcha........
First, this is what the jsp spec has to say in sec 1.14.1
When using scriptlet expressions, the expression must
appear by itself (multiple expressions, and mixing of expressions and string
constants are not permitted). Multiple operations must be performed within the
expression.Simple, isnt it ? All you have to is evaluate the expression as a whole.
<form:toolbaritem id="icon_cancelar" action="<%="javascript:listingAction('" + request.getContextPath() + "/logout.do;')"%>" icon<%= request.getContextPath() + " /images/toolbar/Cancelar_32.gif " %>"/>cheers,
ram. -
Custom tag library called multiple times
Hi ppl ,
I have a custom tag library which i use to populate some menu components. When i do call my custom tag library though , it is called multiple times, use case is as follows.
I have menu tabs and menu bars which thanks to Mr.Brenden is working splendidly as so:-
<af:menuTabs>
<af:forEach var="menuTab" items="#{bindings.menu.vwUserMenuTabRenderer.rangeSet}">
<af:commandMenuItem text="#{menuTab.MenuLabel}"
shortDesc="#{menuTab.MenuHint}"
rendered="true"
immediate="true"
selected="#{sessionScope.selectedMenuId == menuTab.MenuId }"
onclick="fnSetSelectedValue('#{menuTab.MenuId}')" >
</af:commandMenuItem>
</af:forEach>
</af:menuTabs>
<af:menuBar>
<af:forEach var="menuBar" items="#{bindings.menu.vwUserMenuBarRenderer.rangeSet}">
<af:commandMenuItem onclick="return clickreturnvalue()"
onmouseover="dropdownmenu(this, event,#{menuBar.MenuId}, '150px')"
onmouseout="delayhidemenu()"
text="#{menuBar.MenuLabel}"
action="#{menuBar.MenuUri}"
rendered="#{menuBar.ParentId == sessionScope.selectedMenuId}"
immediate="true" />
</af:forEach>
</af:menuBar>
</afc:cache>
now all of this code is within a subview , and just directly below the subview tag , i have the call to my custom tag library:-
<myCustomTagLib:menuCascade />
only issue now is that assuming i have in all 7 menu bar components, the doStartTag is called 7 times. the relevant code within my custom tag class is as follows :-
public int doStartTag() throws JspException {
return (EVAL_BODY_INCLUDE);
public int doEndTag() throws JspException {
try {
declareVariables();
return EVAL_PAGE;
}catch (Exception ioe) {
throw new JspException(ioe.getMessage());
and within my declareVariables method i do an out of the jscript ( out.print(jscript.toString()); ) which is a simple string generated based on certain conditions...
now it seems to be working fine on the front end , but when i view the source of the page, i notice that the declaration is called multiple times, and this happens because the doStartTag method is called multiple times, i haven't even nested the call to the custom tag within the menu components , any clue as to whats going wrong ?
Cheers
KHi,
if you add the following print statement
System.out.println("rendering "+FacesContext.getCurrentInstance().getViewRoot().getViewId());
Then the output in my case is
07/04/24 08:14:04 rendering /BrowsePage.jsp
07/04/24 08:14:05 rendering /otn_logo_small.gif
The image comes from the file system, which means it is rendered by the JSF lifecycle. If you reference the image with a URL then the lifecycle doesn't render the image but only refrences it.
To avoid your prepare render code to be executed multiple times, just check for jsp and jspx file extensions, which will guarantee that your code only executes for JSF pages, not for loaded files.
The reason why this happens is because the JSF filter is set to /faces , which means all files that are loaded through that path
Frank -
I have written a custom tag that I am having problems with. It works on some machines, but not on others. I have a page that uses many 'standard' tags. I have correctly set the URI etc, because all of my other tags work. However, on some machines, my custom tag gives me an error:
attribute does not support request time values
I'm assuming that I have the correct versions of standard.jar etc because all of the regular jstl 1.1 tags work. It is just my custom tag that throws an error.
here is the .tld for my tag:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
<tlib-version>1.1.2</tlib-version>
<jsp-version>1.2</jsp-version>
<short-name>My custom tag</short-name>
<uri>http://my.custom/tags</uri>
<tag>
<name>breadcrumb</name>
<tag-class>tag.BreadcrumbTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>breadcrumbs</name>
<required>true</required>
<rtexprvalue>false</rtexprvalue>
<description>Pass in the list of Breadcrumbs containing the actual information
about what tags need to be rendered on the page.</description>
</attribute>
</tag>
</taglib>
Any thoughts/help greatly appreciated...I encountered the same problem in our environment. I did the same thing as
James. Simply re-initialize all variables in the do end tag.
Also, with the nested tags you use you may also need to implement cloneable
in the inner tag if the outer tag keeps references to all the inner tag
instances.
For instance if the outer tag kept a vector of references to the inner tag,
then you would need to use clone() on the inner tag before adding it to the
vector.
"James Lynn" <[email protected]> wrote in message
news:3af05d29$[email protected]..
> > But
> > with WL 6.0, the cell tag handler reuse the same instance each time the
> cell tag
> > is called and the member field is not reset
>
> I had the same problem. As a work around, I reinitialize everything in my
> doEndTag() method and it works.
>
>
> --
> James Lynn - Lead Software Architect
> Oakscape - Java Powered eBusiness Solutions <http://www.oakscape.com/>
>
>
-
Connection Pooling and JSP Custom Tag Library - is code (inside) the best way/correc?
Hi, can anyone advise as to whether my tag library code (based
on Apache Jakarta Project) will actually achieve connection
pooling functionality across my entire JSP based application? I
am slightly concerned that my OracleConnectionCacheImpl object
may exist multiple times, hence rendering my conection pooling
attempt useless.
package com.solved.tag.dbtags.connection;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import javax.servlet.jsp.tagext.TagSupport;
import javax.servlet.jsp.JspTagException;
import javax.sql.DataSource;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import oracle.jdbc.pool.OracleConnectionCacheImpl;
* <p>JSP tag connection, used to get a
* java.sql.Connection object.</p>
* <p>JSP Tag Lib Descriptor
* <pre>
* <name>connection</name>
<tagclass>com.solved.tag.dbtags.connection.ConnectionTag</t
agclass>
* <bodycontent>JSP</bodycontent>
<teiclass>com.solved.tag.dbtags.connection.ConnectionTEI</t
eiclass>
* <info>Opens a connection based on a jndiName.</info>
* <attribute>
* <name>id</name>
* <required>true</required>
* <rtexprvalue>false</rtexprvalue>
* </attribute>
* </pre>
* @author Matt Shannon
public class ConnectionTag extends TagSupport {
static private OracleConnectionCacheImpl cache = null;
public int doStartTag() throws JspTagException {
try {
Connection conn = null;
if (cache == null) {
try {
InitialContext ic = new InitialContext();
DataSource ds = (DataSource) ic.lookup
("jdbc/pool/OracleCache");
cache = (OracleConnectionCacheImpl)ds;
catch (NamingException ne) {
throw new JspTagException(ne.toString());
conn = cache.getConnection();
pageContext.setAttribute(getId(),conn);
catch (SQLException e) {
throw new JspTagException(e.toString());
return EVAL_BODY_INCLUDE;
package com.solved.tag.dbtags.connection;
import java.sql.Connection;
import java.sql.SQLException;
import javax.servlet.jsp.tagext.TagSupport;
* <p>JSP tag closeconnection, used to close the
* specified java.sql.Connection.<p>
* <p>JSP Tag Lib Descriptor
* <pre>
* <name>closeConnection</name>
<tagclass>com.solved.tag.dbtags.connection.CloseConnectionTag&
lt;/tagclass>
* <bodycontent>empty</bodycontent>
* <info>Close the specified connection. The "conn"
attribute is the name of a
* connection object in the page context.</info>
* <attribute>
* <name>conn</name>
* <required>true</required>
* <rtexprvalue>false</rtexprvalue>
* </attribute>
* </pre>
* @author Matt Shannon
* @see ConnectionTag
public class CloseConnectionTag extends TagSupport {
private String _connId = null;
* The "conn" attribute is the name of a
* page context object containing a
* java.sql.Connection.
* @param connectionId
* attribute name of the java.sql.Connection to
close.
* @see ConnectionTag
public void setConn(String connectionId) {
_connId = connectionId;
public int doStartTag() {
try {
Connection conn = (Connection)pageContext.getAttribute
(_connId);
conn.close();
} catch (SQLException e) {
// failing to close a connection is not fatal
e.printStackTrace();
return EVAL_BODY_INCLUDE;
public void release() {
_connId = null;
package com.solved.tag.dbtags.connection;
import javax.servlet.jsp.tagext.TagData;
import javax.servlet.jsp.tagext.TagExtraInfo;
import javax.servlet.jsp.tagext.VariableInfo;
* TagExtraInfo for the connection tag. This
* TagExtraInfo specifies that the ConnectionTag
* assigns a java.sql.Connection object to the
* "id" attribute at the end tag.
* @author Matt Shannon
* @see ConnectionTag
public class ConnectionTEI extends TagExtraInfo {
public final VariableInfo[] getVariableInfo(TagData data)
return new VariableInfo[]
new VariableInfo(
data.getAttributeString("id"),
"java.sql.Connection",
true,
VariableInfo.AT_END
data-sources.xml:
<?xml version="1.0"?>
<!DOCTYPE data-sources PUBLIC "Orion data-
sources" "http://xmlns.oracle.com/ias/dtds/data-sources.dtd">
<data-sources>
<data-source
class="oracle.jdbc.pool.OracleConnectionCacheImpl"
name="jdbc/pool/OracleCache"
location="jdbc/pool/OracleCache"
url="jdbc:oracle:thin:@oracle1:1521:pdev"
>
<property name="maxLimit" value="15" />
<property name="cacheScheme" value="2" />
<property name="user" value="console" />
<property name="password" value="console" />
<description>
This DataSource is using an Oracle-native DataSource Class so as
to allow Oracle Specific extensions.
A getConnection() call on this DataSource will return
oracle.jdbc.driver.OracleConnection.
The connection returned is a logical connection.
The caching scheme in place is Fixed Wait. Refer below to
possible values.
Dynamic 1
Fixed Wait 2
Fixed Return Null 3
</description>
</data-source>
</data-sources>
many thanks,
Matt.Hi. Show me your pool definition.
Joe
Ramamurthy wrote:
I am using the jsp custom tag library from BEA called sqltags.tld which came with Weblogic 5.1. Currently I am using Weblogic6.1 sp2 on Solaris.
I have created a Connection Pool for Sybase database using the driver com.sybase.jdbc.SybDriver.
When I created jsp page to connect to the connection pool using sqltags custom tag library, I am getting the error
"javax.servlet.jsp.JspException: Failed to write body content
at weblogic.taglib.sql.ConnectionTag.doAfterBody(ConnectionTag.java:43)
at jsp_servlet.__hubwcdata._jspService(__sampletest.java:1014)"
After this message, whenever I try to access the same jsp page I am getting the message
"javax.servlet.jsp.JspException: Failed to load JDBC driver: weblogic.jdbc.pool.D
river
at weblogic.taglib.sql.ConnectionTag.doStartTag(ConnectionTag.java:34)
at jsp_servlet.__hubwcdata._jspService(__sampletest.java:205)".
Can you please help me the reason why this problem is happening and how to fix this ?
This problem doexn't happen consistently. This occurs once in a while.
I tried to increase Login delay Seconds parameter in the Connection Pool to 15 sec. It didn't help me much.
Thanks for your help !!!
Ram -
Is possible to write a custom tag inside another custom tag ??
Hi
I�m trying to reduce the time needed to code mi app presentation layer, it uses some custom tags with certain configuration, i would like to know if its possible to do something like this inside my custom tag doAfterBody().
public int doAfterBody() throws JspException {
JspWriter writer=bodyContent.getEnclosingWriter();
try {
writer.print("<customTag:myAnotherTag someEspecificConfigurationParams="someEspecificValues"/>");
} catch (IOException e) {
pageContext.getServletContext().log("Error: "+e.getMessage());
}return SKIP_BODY;
}The goal is to simplify the jsp code because the configuration params for the custom tags (css styles and similar) are allways the same.
That don�t work, it simply prints <customTag:myAnotherTag/> in screen but the tag is not evaluated, i�ve tried too something like
public int doAfterBody() throws JspException {
if (repeat) {
JspWriter writer = bodyContent.getEnclosingWriter();
try {
writer.print("<customTag:myAnotherTag/>");
} catch (IOException e) {
pageContext.getServletContext().log("Error: " + e.getMessage());
repeat = false;
return EVAL_BODY_AGAIN;
return SKIP_BODY;
}And it doesn�t worked worked. Maybe using the taghandler classes and calls to the doAfterBody could make it work, but when you need to nest tags it could be a little hell of coupling calls, so before doing it i would like to know if what i want is possible. After reading some books i tought it could work because the stack of out objects, but i can�t make it work.
Another idea is to inherit from tagHandler and override some properties in the tags, but i don�t like the idea to much.
So, can anyone help me??
Thanks.You cannot do that and I have listed out the reason and a possible solution in this post http://forum.java.sun.com/thread.jspa?threadID=697243 from yesterday.
cheers,
ram. -
Hi,
I am trying to develop a custom tag for Marquee in JSF, my usecase is to display a value from managed bean(Dynamically). please find the code below and guide me where i have made mistake
regards
Sandeep
Component class:
package customtags;
import javax.el.ValueExpression;
import javax.faces.component.UIComponentBase;
import javax.faces.context.FacesContext;
public class Marquee extends UIComponentBase {
public static final String COMPONENT_TYPE = "marqueecomp";
public static final String RENDERER_TYPE = "marqueeRenderer";
private Object[] _state = null;
private String value;
public String getValue() {
if (null != this.value) {
return this.value;
ValueExpression _ve = getValueExpression("value");
return (_ve != null) ? (String) _ve.getValue(getFacesContext()
.getELContext()) : null;
public void setValue(String marquee) {
this.value = marquee;
public String getFamily() {
// TODO Auto-generated method stub
return COMPONENT_TYPE;
// public void encodeBegin(FacesContext context) throws IOException {
// ResponseWriter writer = context.getResponseWriter();
// writer.startElement("marquee", this);
// writer.write(getValue());
// writer.endElement("marquee");
public void restoreState(FacesContext context, Object state) {
this._state = (Object[]) _state;
super.restoreState(_context, this._state[0]);
value = (String) this._state[1];
public Object saveState(FacesContext _context) {
if (_state == null) {
_state = new Object[2];
state[0] = super.saveState(context);
_state[1] = value;
return _state;
Tag Class:
package customtags;
import javax.el.ValueExpression;
import javax.faces.component.UIComponent;
import javax.faces.webapp.UIComponentELTag;
public class MarqueeTag extends UIComponentELTag {
protected ValueExpression marquee;
public String getComponentType() {
// TODO Auto-generated method stub
return Marquee.COMPONENT_TYPE;
public String getRendererType() {
// TODO Auto-generated method stub
return Marquee.RENDERER_TYPE;
* protected void setProperties(UIComponent component) {
* super.setProperties(component); Marquee marqComp = (Marquee) component;
* if (marquee != null) { marqComp.setValue(marquee); } }
protected void setProperties(UIComponent component) {
super.setProperties(component);
Marquee marqComp = null;
try {
marqComp = (Marquee) component;
} catch (ClassCastException cce) {
throw new IllegalStateException(
"Component "
+ component.toString()
+ " not expected type. Expected: com.foo.Foo. Perhaps you're missing a tag?");
if (marquee != null) {
//marqComp.setValueExpression("value", marquee);
marqComp.setValue("fsdfsdfsdfsdfsd");
* @return the marquee
public ValueExpression getMarquee() {
return marquee;
* @param marquee
* the marquee to set
public void setMarquee(ValueExpression marquee) {
this.marquee = marquee;
*.tld file*
<?xml version="1.0" encoding="UTF-8"?>
<taglib xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"
version="2.1">
<tlib-version>1.0</tlib-version>
<short-name>marqueecomp</short-name>
<uri>http://tags.org/marquee</uri>
<tag>
<name>marqueeTag</name>
<tag-class>customtags.MarqueeTag</tag-class>
<body-content>empty</body-content>
<attribute>
<description><![CDATA[Your description here]]></description>
<name>id</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description><![CDATA[Your description here]]></description>
<name>value</name>
</attribute>
</tag>
</taglib>
Renderer class:
package customtags;
import java.io.IOException;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.Renderer;
public class MarqueeRenderer extends Renderer {
public void encodeBegin(final FacesContext facesContext,
final UIComponent component) throws IOException {
super.encodeBegin(facesContext, component);
final ResponseWriter writer = facesContext.getResponseWriter();
writer.startElement("DIV", component);
/*String styleClass =
(String)attributes.get(Shuffler.STYLECLASS_ATTRIBUTE_KEY);
writer.writeAttribute("class", styleClass, null);*/
public void encodeEnd(final FacesContext facesContext,
final UIComponent component) throws IOException {
final ResponseWriter writer = facesContext.getResponseWriter();
writer.endElement("DIV");
in Faces-Config:
<component>
<display-name>marqueecomp</display-name>
<component-type>marqueecomp</component-type>
<component-class>customtags.Marquee</component-class>
<component-extension>
<renderer-type>marqueeRenderer</renderer-type>
</component-extension>
</component>
<render-kit>
<renderer>
<component-family>marqueecomp</component-family>
<renderer-type>marqueeRenderer</renderer-type>
<renderer-class>customtags.MarqueeRenderer</renderer-class>
</renderer>
</render-kit>
In class path --->marquee.taglib.xml
<?xml version="1.0"?>
<!DOCTYPE facelet-taglib PUBLIC
"-//Sun Microsystems, Inc.//DTD Facelet Taglib 1.0//EN"
"http://java.sun.com/dtd/facelet-taglib_1_0.dtd">
<facelet-taglib>
<namespace>http://tags.org/marquee</namespace>
<tag>
<tag-name>marqueeTag</tag-name>
<component>
<component-type>marqueecomp</component-type>
<renderer-type>marqueeRenderer</renderer-type>
</component>
</tag>
</facelet-taglib>
*.xhtml file*
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core" xml:lang="en" lang="en"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich" xmlns:mycomp="http://tags.org/marquee">
<head>
<title>DEBTDOC Home Page</title>
<meta http-equiv="keywords" content="enter,your,keywords,here" />
<meta http-equiv="description"
content="A short description of this page." />
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<link rel="stylesheet" type="text/css" href="../css/common.css"></link>
<script language="javascript" src="../script/common.js"></script>
</head>
<body>
<f:view>
<mycomp:marqueeTag value="hello World"></mycomp:marqueeTag>There exist the JSTL SQL taglib, but I don't recommend this. It should only be used for quick development and testing. For database connectivity, rather create a data layer with DAO classes which you on its turn just plug in your business layer (with servlets).
-
How to use a variable of jsp custom tag in my java code?
hi folks,
i got a folderList tag like this:
ArrayList list = new ArrayList(20);
%>
<foo:folderList path="${attributes.newsPath}" var="year" contentType="folder">
<%
list.add(${year.contentEntryName}); // of course, this doesn't work
%>
</foo:folderList>I think, its clear what I want to do. I am just wondering how I can use my Variable "year" in the Java code between <% %>...<% list.add(year.getContentEntryName()); %>
You have to have defined in the custom tag that "var" relates to a scripting variable that you want defined.
<tag>
<variable>
<name-given>var</name-given>
<variable-class>myPackage.myClass</variable-class>
<declare>true</declare>
<scope>NESTED</scope>
</variable>
</tag> Cheers,
evnafets -
Custom tag - setProperties() not called
Hi all,
I've created my first custom tag with it's own component class, Tag Class, Renderer and TLD. However, when the JSP first loads, the encode() method fails in trying to get the attribute values from the attribute Map - the Map is empty. Upon further debugging I can see that the Tag class is called and the setter methods are called for each attribute but the setProperties() method is never called before release(), so the attributes are never stored in the UIComponent's attribute Map.
Anybody know what I'm doing wrong?
Some code:
Tag Class...
public class ListShuttleTag extends UIComponentTag
public void setProperites(UIComponent component)
super.setProperties(component);
ComponentTagHelper.setString(component, "sourceValue", sourceValue);
ComponentTagHelper.setString(component, "targetValue", targetValue);
ComponentTagHelper.setInteger(component, "size", size);
ComponentTagHelper.setInteger(component, "targetListWidth", targetListWidth);
ComponentTagHelper.setInteger(component, "sourceListWidth", sourceListWidth);
ComponentTagHelper.setString(component, "sourceCaption", sourceCaption);
ComponentTagHelper.setString(component, "targetCaption", targetCaption);
...TLD...
<taglib>
<tlib-version>1.1</tlib-version>
<jsp-version>2.1</jsp-version>
<tag>
<name>listShuttle</name>
<tag-class>com.katun.jsf.tag.ListShuttleTag</tag-class>
<description>A listShuttle allows the moving of items from one listBox to another</description>
<!-- General component attributes -->
<attribute>
<name>binding</name>
<description>
A binding that points to a bean property
</description>
</attribute>
<attribute>
<name>id</name>
<description>The client id of this component</description>
</attribute>
<attribute>
<name>rendered</name>
<description>Is this component rendered?</description>
</attribute>
<attribute>
<name>disabled</name>
<description>Is this component disabled?</description>
</attribute>
<attribute>
<name>required</name>
<description>Is this component required?</description>
</attribute>
<!-- listShuttle specific attributes -->
<attribute>
<name>sourceValue</name>
<required>true</required>
<description>A binding for the items in the source list</description>
</attribute>
<attribute>
<name>targetValue</name>
<description>A binding for the items in the target list</description>
</attribute>
<attribute>
<name>size</name>
<description>Defines the number of items visible in each list</description>
</attribute>
<attribute>
<name>sourceListWidth</name>
<description>Width of the source list</description>
</attribute>
<attribute>
<name>targetListWidth</name>
<description>Width of the target list</description>
</attribute>
<attribute>
<name>sourceCaption</name>
<description>Label displayed above the source list</description>
</attribute>
<attribute>
<name>targetCaption</name>
<description>Label displayed above the target list</description>
</attribute>
</tag>
...Gotcha........
First, this is what the jsp spec has to say in sec 1.14.1
When using scriptlet expressions, the expression must
appear by itself (multiple expressions, and mixing of expressions and string
constants are not permitted). Multiple operations must be performed within the
expression.Simple, isnt it ? All you have to is evaluate the expression as a whole.
<form:toolbaritem id="icon_cancelar" action="<%="javascript:listingAction('" + request.getContextPath() + "/logout.do;')"%>" icon<%= request.getContextPath() + " /images/toolbar/Cancelar_32.gif " %>"/>cheers,
ram.
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