zeam.utils.batch 1.1
Generic Batch support for Zope
License: BSD
Keywords: batch zope

================
zeam.utils.batch
================

This package provides a batch functionality for Zope 2, Zope 3 and Grok.

.. contents::

Example
=======

A very straightforward example. We need to define a context to work
on::

  >>> import grokcore.view as grok
  >>> from persistent import Persistent
  >>> from zope.component import queryMultiAdapter
  >>> from zeam.utils.batch import Batch
  >>> from zeam.utils.batch.interfaces import IBatching

  >>> class Content(Persistent):
  ...     pass


And now, you can define a view which use a batch, and render it::

  >>> class MyViewClass(grok.View):
  ...     grok.context(Content)
  ...
  ...     def update(self):
  ...          fulllist = [1, 2, 3, 4, 5, 6, 7, 8, 9]
  ...          self.myitems = Batch(
  ...                 fulllist , count=3, name='nbs', request=self.request,
  ...                 factory=lambda x: str(x))
  ...
  ...          self.batch = queryMultiAdapter(
  ...                 (self, self.myitems, self.request),
  ...                     IBatching)()
  ...
  ...     template = grok.PageTemplate('''
  ...     <tal:navigation tal:replace="structure view/batch" />
  ...     <span tal:content="item" tal:repeat="item view/myitems" />
  ...     <tal:navigation tal:replace="structure view/batch" />
  ...     ''')

And this work::

  >>> from grokcore.component import testing
  >>> testing.grok_component("view", MyViewClass)
  True

  >>> from zope.publisher.browser import TestRequest
  >>> request = TestRequest()

  >>> root = getRootFolder()
  >>> root['myObject'] = Content()
  >>> myobj = root['myObject']

  >>> view = queryMultiAdapter((myobj, request), name="myviewclass")
  >>> "batchNav" in view()
  True


API
===

``Batch``
   This object implements the batch.

   The batch object is instanciated with the following arguments:

   - a list of the objects to batch

   - the request

   - the number of items per page (as count, default to 10)

   - a name (optional)

   - a factory that will be passed each item before each iteration (optional)

   The batch is an iterable object behaving like a list.
   It only gives access to the set of objects for the current page.

   It provides the number of pages generated and the current position.
   Please refer to the interface, for more information.

   A multi adapter providing ``IBatching`` can render the batch.
   It adapts the context, the batch object and the request. The __call__
   method of this component will return a snippet of HTML containing
   basic controls for your batch: a next and previous link and a direct
   access to the other pages.

``DateBatch``
   This object implements a batch for date range. It follows the same
   API than the regular batch, except:

   - the list of objects is replaced by a callable that takes a
     datetime value has parameter and return a list of objects for the
     given periode

   - the count option is changed to use either the ``BATCH_DAY`` or
     ``BATCH_MONTH`` marker object.


Changelog
=========

1.1 (2012-09-24)
----------------

* Add a new type of batch, AlphabeticalBatch, that like the DateBatch,
  and can be used to iterate through a fixed set of items like letters
  or digits.

* Fix a bug when the ``start`` value is higher than the number of
  element in the batch in the regular batch.

* Add two options ``min`` and ``max`` to the date batch in order to
  define possible limits for it.

1.0 (2011-11-07)
----------------

* Add a new batch component, ``DateBatch``, which is able to browser
  period of years or months.

* ``batch`` is renamed into ``Batch``. Methods have been renamed to
  follow pep8 recommandations (i.e. ``batchLen`` into ``batch_length``).

* Template have been reviewed: values are accessible via the template
  variable ``batch`` insted of directly. This fix an issue of
  compatiblity with Chameleon, where ``next`` could not be defined
  (that's a Python built-in).

0.7 (2010-10-05)
----------------

* Add a __len__ method do a batch object, which returns the number of
  objects viewable via this current batch. Like this, it can be used
  with tal:condition in templates.

* An option keep_form_data on the view prevent to include posted form
  data in generated links (sometime you want them, some other you
  don't).

0.6 (2010-07-15)
----------------

* Generated batch links can include other parameters in the link. That
  let you batch form results for instance.


0.5 (2009-11-17)
----------------

* Batching views have two new properties: ``first`` and ``last`` which
  gives links to the first and last batch.

0.4.1 (2009-10-16)
------------------

* Corrected the broken distribution that was missing the i18n folder.

0.4 (2009-10-16)
----------------

.. note::

   This release is incompatible with previous ones. You are recomanded
   to review and adapt your code in order to use it.

* Added README.txt as a doctest [trollfot]
* The rendering is made by a IPageTemplate component, not longer by
  the Batching itself. [trollfot]
* We no longer use the IBatchedContent. It has been removed. [trollfot]
* `zeam.utils.batch` is now fully grokked. [trollfot]
* batchView has been renamed Batching. [trollfot]
* You adapt the batch with the view on which you display the batch:
  its name will keep when generating links,
* Batch can be *disabled* with a count of 0,
* Add translations for french, english and dutch.

0.3 (2008-10-18)
----------------

* Fix and add tests,
* Don't display batch navigation if everything fits on one page,
* No more special links are generated for the first page of the batch.

0.2
---

* Initial release