RE: outputting expression logic
Well I am not sure what to do... I don't want to drag multiple variables and logic and get those all rigged up in my page from the component just to do a single method... or two that take multiple parameters and reference multiple variables from within. It would be nice if we had an arithmetic operator kinda like prop: math: and maybe a function operator func: so i can keep all my component logic self contained. Any last ditch efforts to accommodate my dreams ? Ken To: users@tapestry.apache.org; kcola...@live.com Subject: Re: outputting expression logic Date: Fri, 16 Sep 2011 07:48:41 -0300 From: thiag...@gmail.com On Thu, 15 Sep 2011 23:53:18 -0300, Ken in Nashua kcola...@live.com wrote: I guess I am asking for an ognl engine... to do these calculations within tml files Are you really sure you want to have logic in your template and make it look like JSP (which sucks), as Steve said? Mixing output generation and logic is a recipe for confusion. When I started working with T5 I've also missed OGNL, but later I got used to it and I use almost just property expressions exclusively since then. ChenilleKit has an OGNL binding. be nice if there were an expression operator in T5 to do these... That's not going to happen. This was dropped from T5 on purpose. guess I will have to make a java method... This is the canonical approach. Logic belongs in Java classes. It does seem to me that you're trying to write T5 thinking in T4 terms. I don't advise you to do that. The main concepts are mostly the same, but the implementation is very, very different. -- Thiago H. de Paula Figueiredo Independent Java, Apache Tapestry 5 and Hibernate consultant, developer, and instructor Owner, Ars Machina Tecnologia da Informação Ltda. http://www.arsmachina.com.br
Re: outputting expression logic
Wow, I wouldn't want to have to maintain an app full of tml files like that. I think you're not realizing yet how much more maintainable a good clean T5-style template really is. Java is so much more expressive for logic anyway. Bob Harner On Sep 17, 2011 5:20 PM, Ken in Nashua kcola...@live.com wrote: Thanks Thiago... I didn't think it unreasonable to have fundamental ops to take code like this... span jwcid=foreachitem@For source=ognl:collection value=ognl:currentObject index=ognl:index span jwcid=@If condition=ognl:okToRenderItem span jwcid=@If condition=ognl:( @java.lang.Math@min(tableColumns, itemsPerPage) ) span jwcid=@If condition=ognl:((index - cursor) % @java.lang.Math@min(tableColumns, itemsPerPage) ) == 0 span jwcid=@Insert value=/trtr raw=true/ /span /span and have tap5 honor the same semantic (arithmetic and method calls) in some way or another... I refuse to violate the page code and self contained components is pure tapestry anyway. It seems I need chenelle... Can you recommend a chenelle version for tap 5.3.0 ? Thank You
Re: outputting expression logic
I've been developing with Tapestry since version 3. I finally reached the
conclusion that templates like below are evil. :) The main reason for them in
T4 was template reloading, so you had fast turnaround time when developing. In
T5, you get page component class reloading, as well, so the primary driver
behind putting any logic in the template is gone. Here are a few reasons why I
find templates like below evil:
1) It makes pages more brittle and prone to break during refactoring
2) It makes it easier for a designer (or anyone, really) to hose the
page/component (there's just a lot more stuff in there to break by accident)
3) It's considerably more difficult to understand/read (and therefore to
maintain!)
Here's a T5 version of your snippet below:
.tml:
t:loop source=collection value=currentObject index=index
t:if test=okToRenderItem
t:if test=hasColumnsAndItems
t:if test=atRowEnd
t:outputraw value=trTags/
/t:if
/t:if
/t:if
/t:loop
.java:
@Property
private int index;
@Property
private Object currentObject;
public String getTrTags() {
return tr/tr;
}
public boolean isOkToRenderItem() { /* whatever your original method was */ }
public boolean isHasColumnsAndItems() {
return Math.min(tableColumns, itemsPerPage) 0;/*since you're
referencing these as properties in your page, I'm assuming they are available
as properties in your page already*/
}
public boolean isAtRowEnd() {
return ((index - cursor) % Math.min(tableColumns, itemsPerPage)) ==
0;/* again assuming that cursor, tableColumns, and itemsPerPage are available
as properties in your page/component class... possibly as parameter values?)*/
}
Maybe it's just me... I like the T5 version a lot better. :)
Robert
On Sep 17, 2011, at 9/174:19 PM , Ken in Nashua wrote:
Thanks Thiago... I didn't think it unreasonable to have fundamental ops to
take code like this...
span jwcid=foreachitem@For source=ognl:collection
value=ognl:currentObject index=ognl:index
span jwcid=@If condition=ognl:okToRenderItem
span jwcid=@If condition=ognl:(
@java.lang.Math@min(tableColumns, itemsPerPage) )
span jwcid=@If condition=ognl:((index -
cursor) % @java.lang.Math@min(tableColumns, itemsPerPage) ) == 0
span jwcid=@Insert value=/trtr
raw=true/
/span
/span
and have tap5 honor the same semantic (arithmetic and method calls) in some
way or another...
I refuse to violate the page code and self contained components is pure
tapestry anyway.
It seems I need chenelle...
Can you recommend a chenelle version for tap 5.3.0 ?
Thank You
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RE: outputting expression logic
Rob, Thanks for the constructive criticism. I will give this a whirl... like what I see... I am all for good form... and one of the nice things I am excited about T5 is that it promotes a ton of loose options for achieving good form. Appreciate the help and will let you know how I make out. - cheers KEN
RE: outputting expression logic
Thanks Rob... code ran as-is... auto-paging layout looks sweet
I hope to finish this guy up and publish for public consumption by mid week or
sooner... I just need to QA the action auto-paging links.
Thanks... appreciate the help
TML
t:Loop id=foreachitem source=collection
value=currentObject index=index
t:If test=okToRenderItem
t:if test=hasColumnsAndItems
t:if test=atRowEnd
t:outputraw value=trTags/
/t:if
/t:if
JAVA
public boolean isHasColumnsAndItems() {
return Math.min(tableColumns, itemsPerPage) 0;
}
public boolean isAtRowEnd() {
return ((index - cursor) % Math.min(tableColumns, itemsPerPage)) == 0;
}
public String getTrTags() {
return tr/tr;
}
Re: outputting expression logic
span jwcid=@Insert value=/trtr raw=true/
I don't think it's ever a good idea to output partial HTML in your
page like this.
I'll throw one more implementation into the ring.
!-- Usage Example --
t:gallery entriesPerRow=4 entry=var:galleryEntry source=1..21
${var:galleryEntry}
/t:gallery
!-- Gallery.tml --
div xmlns:t=http://tapestry.apache.org/schema/tapestry_5_1_0.xsd;
table
t:loop source=rows value=columns
tr
t:loop source=columns value=entry
td
t:body/
/td
t:if test=needsPadding
td colspan=${padding}#160;/td
/t:if
/t:loop
/tr
/t:loop
/table
/div
/**
* Gallery.java
*/
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.annotations.Property;
import java.util.Iterator;
import java.util.NoSuchElementException;
public class Gallery {
@Parameter(required = true)
private Iterable source;
@Parameter(required = true)
@Property
private Object entry;
@Parameter(required = true)
private int entriesPerRow;
@Parameter
private int maxRows;
@Property
private WrappedIterable rows;
@Property
private LimitedIterable columns;
void setupRender() {
rows = new WrappedIterable(source);
}
public boolean getNeedsPadding() {
return !rows.iterator.hasNext() columns.count entriesPerRow;
}
public int getPadding() {
return entriesPerRow - columns.count;
}
public class WrappedIterable implements IterableLimitedIterable {
private Iterator iterator;
int rows = 0;
private WrappedIterable(Iterable iterable) {
iterator = iterable.iterator();
}
public IteratorLimitedIterable iterator() {
return new IteratorLimitedIterable() {
public boolean hasNext() {
return (maxRows = 0 || rows maxRows)
iterator.hasNext();
}
public LimitedIterable next() {
if (hasNext()) {
++rows;
return new LimitedIterable(iterator, entriesPerRow);
}
throw new NoSuchElementException();
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}
public class LimitedIterable implements Iterable {
int count = 0;
private final Iterator iterator;
private int limit;
private LimitedIterable(Iterator iterator, int limit) {
this.iterator = iterator;
this.limit = limit;
}
public Iterator iterator() {
return new IteratorObject() {
public boolean hasNext() {
return count limit iterator.hasNext();
}
public Object next() {
if (hasNext()) {
++count;
return iterator.next();
}
throw new NoSuchElementException();
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}
}
Josh
On Sat, Sep 17, 2011 at 6:40 PM, Ken in Nashua kcola...@live.com wrote:
Rob,
Thanks for the constructive criticism.
I will give this a whirl... like what I see...
I am all for good form... and one of the nice things I am excited about T5 is
that it promotes a ton of loose options for achieving good form.
Appreciate the help and will let you know how I make out.
- cheers
KEN
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Re: outputting expression logic
On Thu, 15 Sep 2011 23:53:18 -0300, Ken in Nashua kcola...@live.com wrote: I guess I am asking for an ognl engine... to do these calculations within tml files Are you really sure you want to have logic in your template and make it look like JSP (which sucks), as Steve said? Mixing output generation and logic is a recipe for confusion. When I started working with T5 I've also missed OGNL, but later I got used to it and I use almost just property expressions exclusively since then. ChenilleKit has an OGNL binding. be nice if there were an expression operator in T5 to do these... That's not going to happen. This was dropped from T5 on purpose. guess I will have to make a java method... This is the canonical approach. Logic belongs in Java classes. It does seem to me that you're trying to write T5 thinking in T4 terms. I don't advise you to do that. The main concepts are mostly the same, but the implementation is very, very different. -- Thiago H. de Paula Figueiredo Independent Java, Apache Tapestry 5 and Hibernate consultant, developer, and instructor Owner, Ars Machina Tecnologia da Informação Ltda. http://www.arsmachina.com.br - To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org For additional commands, e-mail: users-h...@tapestry.apache.org
RE: outputting expression logic
Thanks Thiago... logically it makes sense... just trying to avoid code bloat in the java module and going for the short cut drill into the object at the tml level. I do think moving the logic to java will prompt the developer to make things more reasonably understandable by working in realistic operations that will be understood better in the tml file... anyway... getting closer... gallery widget pending ciao To: users@tapestry.apache.org; kcola...@live.com Subject: Re: outputting expression logic Date: Fri, 16 Sep 2011 07:48:41 -0300 From: thiag...@gmail.com On Thu, 15 Sep 2011 23:53:18 -0300, Ken in Nashua kcola...@live.com wrote: I guess I am asking for an ognl engine... to do these calculations within tml files Are you really sure you want to have logic in your template and make it look like JSP (which sucks), as Steve said? Mixing output generation and logic is a recipe for confusion. When I started working with T5 I've also missed OGNL, but later I got used to it and I use almost just property expressions exclusively since then. ChenilleKit has an OGNL binding. be nice if there were an expression operator in T5 to do these... That's not going to happen. This was dropped from T5 on purpose. guess I will have to make a java method... This is the canonical approach. Logic belongs in Java classes. It does seem to me that you're trying to write T5 thinking in T4 terms. I don't advise you to do that. The main concepts are mostly the same, but the implementation is very, very different. -- Thiago H. de Paula Figueiredo Independent Java, Apache Tapestry 5 and Hibernate consultant, developer, and instructor Owner, Ars Machina Tecnologia da Informação Ltda. http://www.arsmachina.com.br
Re: outputting expression logic
Hi
Tapestry property expressions do not support arithmetic operations. See
http://tapestry.apache.org/property-expressions.html
for complete list of operations supported
On Fri, Sep 16, 2011 at 7:30 AM, Ken in Nashua kcola...@live.com wrote:
Hi All,
I have this expression in a component definition...
t:label for = tableColumnsSelect ${cursor} + 1 /t:label
For my case cursor is initially 0
After render... I view page source and I see the following...
0 + 1
when what I actually wanted to see is... the sum of the expression and the
value rendered...
1
Any tips on how i can do this ? Is there an arithmetic or expression operator
that I can prefix before my ${cursor} + 1 ?
Thanks
--
Regards
Taha Hafeez Siddiqi (tawus)
http://tawus.wordpress.com
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RE: outputting expression logic
t:outputRaw value=(${cursor} + 1)/
this seems to produce 0 + 1 instead of the desired 1
all i am trying to do is have the arithmetic performed before the output
thanks
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: outputting expression logic
Date: Thu, 15 Sep 2011 22:00:46 -0400
Hi All,
I have this expression in a component definition...
t:label for = tableColumnsSelect${cursor} + 1/t:label
For my case cursor is initially 0
After render... I view page source and I see the following...
0 + 1
when what I actually wanted to see is... the sum of the expression and the
value rendered...
1
Any tips on how i can do this ? Is there an arithmetic or expression operator
that I can prefix before my ${cursor} + 1 ?
Thanks
RE: outputting expression logic
I guess I am asking for an ognl engine... to do these calculations within tml
files
be nice if there were an expression operator in T5 to do these...
guess I will have to make a java method...
any solutions or canonical approach are appreciated...
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: RE: outputting expression logic
Date: Thu, 15 Sep 2011 22:47:03 -0400
t:outputRaw value=(${cursor} + 1)/
this seems to produce 0 + 1 instead of the desired 1
all i am trying to do is have the arithmetic performed before the output
thanks
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: outputting expression logic
Date: Thu, 15 Sep 2011 22:00:46 -0400
Hi All,
I have this expression in a component definition...
t:label for = tableColumnsSelect${cursor} + 1/t:label
For my case cursor is initially 0
After render... I view page source and I see the following...
0 + 1
when what I actually wanted to see is... the sum of the expression and the
value rendered...
1
Any tips on how i can do this ? Is there an arithmetic or expression operator
that I can prefix before my ${cursor} + 1 ?
Thanks
RE: outputting expression logic
So far I have to clutter up my component with this.. wish I could just do
it in the tml like ognl as-is in t-4.1.2
not interested in chenelle
@Persist(session)
@Property
private int cursorStartPosition;
@Persist(session)
@Property
private int cursorEndPosition;
@Persist(session)
@Property
private int collectionSize;
@BeginRender
public void beginRender()
{
itemsPerPage = 50;
tableColumns = 3;
/**
* auto paging metrics
*/
cursorStartPosition = cursor + 1;
cursorEndPosition = cursor + (collection == null ? 0 :
java.lang.Math.min(collection.size(), itemsPerPage));
collectionSize = (collection == null ? 0 : collection.size());
}
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: RE: outputting expression logic
Date: Thu, 15 Sep 2011 22:53:18 -0400
I guess I am asking for an ognl engine... to do these calculations within tml
files
be nice if there were an expression operator in T5 to do these...
guess I will have to make a java method...
any solutions or canonical approach are appreciated...
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: RE: outputting expression logic
Date: Thu, 15 Sep 2011 22:47:03 -0400
t:outputRaw value=(${cursor} + 1)/
this seems to produce 0 + 1 instead of the desired 1
all i am trying to do is have the arithmetic performed before the output
thanks
kcola...@live.com
From: kcola...@live.com
To: users@tapestry.apache.org
Subject: outputting expression logic
Date: Thu, 15 Sep 2011 22:00:46 -0400
Hi All,
I have this expression in a component definition...
t:label for = tableColumnsSelect${cursor} + 1/t:label
For my case cursor is initially 0
After render... I view page source and I see the following...
0 + 1
when what I actually wanted to see is... the sum of the expression and the
value rendered...
1
Any tips on how i can do this ? Is there an arithmetic or expression operator
that I can prefix before my ${cursor} + 1 ?
Thanks
Re: outputting expression logic
Some call it clutter, I call it refactor safe!
A problem I often saw with T4 is people tended to push as much logic
as they could into the .tml - with the pain they encountered
afterwards, I wondered why they didn't just stick to JSPs?!
And
t:outputRaw value=(${cursor} + 1)/
does nothing more than
${cursor} + 1
as all outputRaw does is evaluate your expression and write out as
raw, un-escaped HTML.
Steve.
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