geirm 00/12/03 18:06:53
Modified: src/java/org/apache/velocity/runtime/directive Foreach.java
Log:
Big change is that introspection etc is handled at exec time ( via render() ) rather
than setup through init. Small change is that we save and restore the value of the
loop reference if it exists...
Revision Changes Path
1.27 +62 -134
jakarta-velocity/src/java/org/apache/velocity/runtime/directive/Foreach.java
Index: Foreach.java
===================================================================
RCS file:
/home/cvs/jakarta-velocity/src/java/org/apache/velocity/runtime/directive/Foreach.java,v
retrieving revision 1.26
retrieving revision 1.27
diff -u -r1.26 -r1.27
--- Foreach.java 2000/11/28 04:16:21 1.26
+++ Foreach.java 2000/12/04 02:06:52 1.27
@@ -85,7 +85,7 @@
*
* @author <a href="mailto:[EMAIL PROTECTED]">Jason van Zyl</a>
* @author <a href="mailto:[EMAIL PROTECTED]">Geir Magnusson Jr.</a>
- * @version $Id: Foreach.java,v 1.26 2000/11/28 04:16:21 jvanzyl Exp $
+ * @version $Id: Foreach.java,v 1.27 2000/12/04 02:06:52 geirm Exp $
*/
public class Foreach extends Directive
{
@@ -157,105 +157,71 @@
* it is immutable.
*/
private String elementKey;
-
+
+ /**
+ * simple init - init the tree and get the elementKey from
+ * the AST
+ */
public void init(Context context, Node node) throws Exception
{
- Object sampleElement = null;
- Object listObject = null;
-
+ super.init( context, node );
+
+ /*
+ * this is really the only thing we can do here as everything
+ * else is context sensitive
+ */
+
elementKey = node.jjtGetChild(0).getFirstToken().image.substring(1);
+ }
+ private Iterator getIterator( Context context, Node node )
+ {
+ Object listObject = null;
+
/*
- * This is a refence node and it needs to
- * be inititialized.
+ * get our list object, and punt if it's null.
*/
- node.jjtGetChild(2).init(context, null);
+
listObject = node.jjtGetChild(2).value(context);
- /*
- * If the listObject is null then we know that this
- * whole foreach directive is useless. We need to
- * throw a ReferenceException which is caught by
- * the SimpleNode.init() and logged. But we also need
- * to set a flag so that the rendering of this node
- * is ignored as the output would be useless.
- */
-
- /*
- * Slight problem with this approach. The list object
- * may have been #set previously, this usually wouldn't
- * be the case, but this check should be moved into
- * the rendering phase.
- */
if (listObject == null)
- {
- node.setInvalid();
- throw new ReferenceException("#foreach", node.jjtGetChild(2));
- }
+ return null;
/*
* Figure out what type of object the list
- * element is so that we don't have to do it
- * everytime the node is traversed.
- * if (listObject instanceof Object[])
+ * element is, and get the iterator for it
*/
- if (listObject instanceof Object[])
+
+ if (Introspector.implementsMethod(listObject, "iterator"))
{
+ if (((Collection) listObject).size() == 0)
+ return null;
+
+ return ((Collection) listObject).iterator();
+ }
+ else if (listObject instanceof Object[])
+ {
Object[] arrayObject = ((Object[]) listObject);
if (arrayObject.length == 0)
- {
- node.setInfo(INFO_EMPTY_LIST_OBJECT);
- }
- else
- {
- node.setInfo(INFO_ARRAY);
- sampleElement = arrayObject[0];
- }
+ return null;
+
+ return new ArrayIterator( arrayObject );
}
- else if (Introspector.implementsMethod(listObject, "iterator"))
- {
- if (((Collection) listObject).size() == 0)
- {
- node.setInfo(INFO_EMPTY_LIST_OBJECT);
- }
- else
- {
- node.setInfo(INFO_ITERATOR);
- sampleElement = ((Collection) listObject).iterator().next();
- }
- }
else if (Introspector.implementsMethod(listObject, "values"))
{
if (((Map) listObject).size() == 0)
- {
- node.setInfo(INFO_EMPTY_LIST_OBJECT);
- }
- else
- {
- node.setInfo(INFO_MAP);
- sampleElement = ((Map) listObject).values().iterator().next();
- }
+ return null;
+
+ return ((Map) listObject).values().iterator();
}
else
- {
- // If it's not an array or an object that provides
- // an iterator then the node is invalid and should
- // not be rendered.
- node.setInvalid();
- Runtime.warn ("Could not determine type of iterator for #foreach loop
");
- throw new NodeException ("Could not determine type of iterator for
#foreach loop " , node);
- }
-
- // This is a little trick so that we can initialize
- // all the blocks in the foreach properly given
- // that there are references that refer to the
- // elementKey name.
- if (sampleElement != null)
{
- context.put(elementKey, sampleElement);
- super.init(context, node);
- context.remove(elementKey);
+ /*
+ * we have no clue what this is
+ */
+ Runtime.warn ("Could not determine type of iterator for #foreach loop
for " + node.jjtGetChild(2).getFirstToken().image);
+ return null;
}
}
@@ -264,69 +230,24 @@
{
int counter;
Iterator i;
- Object listObject = null;
/*
- * If the node has been set to invalid then it is because
- * the list object placed in the context is not an array,
- * does not provide an Iterator, or is not Map. In these
- * cases there is nothing we can do, and nothing will
- * be rendered.
+ * do our introspection to see what our collection is
*/
- if (node.isInvalid())
- return false;
-
- if (node.getInfo() == INFO_EMPTY_LIST_OBJECT)
- {
- /*
- * If the list object had no elements
- * then lets try to init again. If the list
- * object is still empty then an exception
- * will be thrown again. But we will keep
- * trying!
- */
- synchronized(this)
- {
- /*
- * Check again for other threads that
- * got through above. Don't want to
- * have to synchronize on every render,
- * but we don't want to init() multiple
- * times here either. A few threads might
- * get into this block, but only one thread
- * will try the init().
- */
- if (node.getInfo() == INFO_EMPTY_LIST_OBJECT)
- {
- try
- {
- init(context, node);
-
- /*
- * Check again, if the list is still
- * empty then return false.
- */
- if (node.getInfo() == INFO_EMPTY_LIST_OBJECT)
- return false;
- }
- catch (Exception e)
- {
- return false;
- }
- }
- }
- }
-
- listObject = node.jjtGetChild(2).value(context);
- if (node.getInfo() == INFO_ARRAY)
- i = new ArrayIterator((Object[]) listObject);
- else if (node.getInfo() == INFO_MAP)
- i = ((Map) listObject).values().iterator();
- else
- i = ((Collection) listObject).iterator();
+ i = getIterator( context, node );
+
+ if ( i == null)
+ return false;
counter = COUNTER_INITIAL_VALUE;
+
+ /*
+ * save the element key if there is one
+ */
+
+ Object o = context.get( elementKey );
+
while (i.hasNext())
{
context.put(COUNTER_NAME, new Integer(counter));
@@ -337,7 +258,14 @@
context.remove(COUNTER_NAME);
context.remove(elementKey);
-
+
+ /*
+ * restores element key if exists
+ */
+
+ if (o != null)
+ context.put( elementKey, o );
+
return true;
}
