Provides the core code to iterate next and previous through a table or view
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Key: OFBIZ-1723
URL: https://issues.apache.org/jira/browse/OFBIZ-1723
Project: OFBiz
Issue Type: New Feature
Components: ALL COMPONENTS
Reporter: Skip Dever
Priority: Minor
This enhancement provides the java code to allow an application to be written
that allows the user to click "Next" and "Previous" buttons to cycle through a
table or view. Included in the download is EntityListIteratorContainer.java,
and a sample bsh script and .ftl file that demonstrate how to use it.
EntityListIteratorContainer.java creates an instance of EntityListIterator that
is used to provide the background services in an atomic way, i.e. each
operation (re)creates an EntityListIterator bounded by begin/commit operations
and the iterator is closed at the end of each operation.
To use the class, use one of the EntityListIterator based instantiators and
then call find(). If find() is not called first, the list is assumed to be
positioned before the beginning of the table and next() returns the first
record.
Calling previous() when at the beginnng of the file returns the last record.
This code is self contained and the list goes away and is garbage collected
after 5 minutes of non-use on a timer.
The bash script accounts for this by recreating the list and doing a find().
The key to using this is found in the sample ftl file. Which has the tag:
<input type="hidden" name="listIterator" value="${listIterator}"/>
The bash script puts the listIterator in the context and a text reference of
the form <url>[EMAIL PROTECTED] is passed when the form is submitted.
This is dereferenced in the subsequent bash script with the lines:
String containerString = (String)parameters.get("listIterator");
if(containerString != null)
container =
EntityListIteratorContainer.findInstance(containerString);
This retrieves the previously constructed listIterator and next() and
previous() operations can be used on it as shown in the sample bash script.
It all works a charm. I have tested this on a medium sized table with 10000
entries and the first find() consumes about 80msecs. Subsequent next() and
previous() calls consume < 20msecs.
What would make this even better is a way to add a listener on the servlet
controller so that when the user moved to a different url base, the instance
could be trashed. But, alas, I can find no such interface.
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