LinkTool patch - was: Re:AbstractPagerTool

[Matthew Van Horn <ma...@ashleyassociates.co.jp>]

> -----Original Message-----
> From: Nathan Bubna [mailto:nathan@esha.com] 
> Sent: Wednesday, August 11, 2004 1:39 AM
> To: Velocity Users List
> Subject: Re: AbstractPagerTool
> 
> 
> Matthew Van Horn said:
> I am thinking there should be a
> updateQueryData(String name, String value) which would add the 
> name/value but if it already existed, it would overwrite the old 
> value.

sounds useful, but it would probably be better named
setQueryData(String,Object).

> Right now, I am using too much logic in my template to do this. 
> (checking the name of each param in a loop, before calling 
> addQueryData) It is not as maintainable as I'd like.
>
> What do you think of this idea? The way the QueryPairs are stored, I 
> probably have to do the same loop w/ conditional over the ArrayList, 
> but at least template designers don't have to hard code the parameter 
> names to check for.

it's a good idea.  wanna contribute a patch? (preferrably as diff -u)

Here is an example of how I use the new method:
#set($searchlink = $link.setAction('myAction'))

<!-- copy all the existing key=value pairs -->
#foreach($name in $request.parameterNames)
	#set($searchlink = $searchlink.setQueryData($name,
$request.getParameter($name)))
#end

<!-- and no worries about duplicating pagesize and index anymore ->
#set($searchlink =
$searchlink.setQueryData("pagesize",$!pager.itemsPerPage))
#if( $pager.prevIndex )
	<a
href="$searchlink.setQueryData('index',$!pager.prevIndex)">PREVIOUS</a>
#end


Here is the patch:

Index: LinkTool.java
===================================================================
RCS file:
/home/cvspublic/jakarta-velocity-tools/src/java/org/apache/velocity/tool
s/view/tools/LinkTool.java,v
retrieving revision 1.15
diff -u -r1.15 LinkTool.java
--- LinkTool.java	12 Mar 2004 20:30:32 -0000	1.15
+++ LinkTool.java	11 Aug 2004 03:20:41 -0000
@@ -20,6 +20,7 @@
 import java.lang.reflect.Method;
 import java.net.URLEncoder;
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 
 import javax.servlet.http.HttpServletRequest;
@@ -29,7 +30,6 @@
 
 import org.apache.velocity.app.Velocity;
 import org.apache.velocity.tools.view.context.ViewContext;
-import org.apache.velocity.tools.view.tools.ViewTool;
 
 /**
  * View tool to make building URIs pleasant and fun! 
@@ -166,6 +166,40 @@
         return copy;
     }
 
+	/**
+	 * For internal use.
+	 *
+	 * Copies 'that' LinkTool into this one and adds the new query
data, overwriting any existing parameter with the same name.
+	 *
+	 * @param pair the query parameter to add or update
+	 */
+	protected LinkTool copyOver(QueryPair pair)
+	{
+		LinkTool copy = duplicate();
+		if (copy.queryData != null)
+		{
+			// set the copy's query data to a shallow clone
of 
+			// the current query data array
+			copy.queryData =
(ArrayList)this.queryData.clone();
+		}
+		else
+		{
+			copy.queryData = new ArrayList();
+		}
+		
+		for (Iterator iter = copy.queryData.iterator();
iter.hasNext();) {
+			QueryPair element = (QueryPair) iter.next();
+			if (element.key.equals(pair.key)) {
+				iter.remove();
+			}			
+		}
+		//add new pair to this LinkTool's query data
+		copy.queryData.add(pair);
+		return copy;
+	}
+	
+	
+	
 
     /**
      * For internal use.
@@ -366,6 +400,25 @@
     {
         return copyWith(new QueryPair(key, value));
     }
+
+
+	/**
+	 * <p>Adds a key=value pair to the query data. This returns a
new LinkTool 
+	 * containing both a copy of this LinkTool's query data and the
new data.
+	 * Query data is URL encoded before it is appended.</p>
+	 * 
+	 * <p>If the key already exists in the query data, the existing
value is overwritten, 
+	 * otherwise the behaviour is identical to {@link
#addQueryData}</p>
+	 *
+	 * @param key key of new query parameter
+	 * @param value value of new query parameter
+	 *
+	 * @return a new instance of LinkTool
+	 */
+	public LinkTool setQueryData(String key, Object value)
+	{
+		return copyOver(new QueryPair(key, value));
+	}
 
     
     /**


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