com.codename1.rad.processing (coderad-common 2.0-pre3 API)

Class Summary
Class	Description
Result		Note	This class is based on the core `Result` class, but has been modified to improve performance, fix bugs, and add support for additional syntaxes.

<h1>XPath based expression language designed to assist in JSON/XML parsing/generating</h1> <p> The Result class provides a subset of <a href="http://www.w3schools.com/xsl/xpath_intro.asp">XPath</a>, but it is not limited to just XML documents, it can also work with JSON documents, and even with raw Map objects. </p>

<p>
    As an example, we'll demonstrate how to process a response from the
    <a href="https://developers.google.com/maps/documentation/geocoding/">Google Reverse Geocoder API</a>.
    Lets start with this XML snippet:
</p>

<script src="https://gist.github.com/codenameone/6470330d1a30d30760ed.js"></script>

<p>
     We want to extract some of the data above into simpler string results. We can do this using:
</p>

<script src="https://gist.github.com/codenameone/966f9061a610330f5d03.js"></script>

<p>
    If you are at all familiar with processing responses from webservices, you will notice that what would
    normally require several lines of code of selecting and testing nodes in regular java can now be
    done in a single line using the new path expressions.
</p>

<p>
     In the code above, input can be any of:
</p>
<ul>
    <li>InputStream directly from ConnectionRequest.readResponse(java.io.InputStream)</li>
    <li>XML or JSON document in the form of a  String</li>
    <li>XML DOM Element returned from XMLParser</li>
    <li>JSON DOM Map returned from JSONParser</li>
</ul>

<p>
    To use the expression processor when calling a webservice, you could use something like the following to
    parse JSON (notice this is interchangeable between JSON and XML):
</p>

<script src="https://gist.github.com/codenameone/16c2752f8eebbfe245cc.js"></script>

<p>
    The returned JSON looks something like this (notice it's snipped because the data is too long):
</p>

<script src="https://gist.github.com/codenameone/58a213197634fb8ea4c3.js"></script>

<img src="https://www.codenameone.com/img/developer-guide/processing-package.png" alt="Running the geocode sample above in the simulator">

<p>The XML processor currently handles global selections by using a double slash anywhere within the
    expression, for example:</p>

<blockquote><strong>NOTE:</strong> Notice that Google's JSON webservice uses plural form for each of
    the node names in that API  (ie. results, address_components, and types) where they don't in the XML services
    (ie result, address_component etc.).</blockquote>

<h2>Example 2</h2>
<p>It also possible to do some more complex expressions.  We'll use the following XML fragment for the next batch of examples:</p>

<script src="https://gist.github.com/codenameone/c51305d0bd2f0a67b861.js"></script>

<p>Above, if you want to select the IDs of all players that are ranked in the top 2, you can use an
    expression like:</p>
<script src="https://gist.github.com/codenameone/a334a5705c37f63d6590.js"></script>

<p>(Notice above that the expression is using an attribute for selecting both rank and id.  In JSON
    documents, if you attempt to select an attribute, it will look for a child node under the attribute name you ask for).</p>

<p>If a document is ordered, you might want to select nodes by their position, for example:</p>
<script src="https://gist.github.com/codenameone/36174cb1e0db7539f46f.js"></script>

<p>It is also possible to select parent nodes, by using the �..' expression.  For example:</p>
 <script src="https://gist.github.com/codenameone/dac601cd4ce442e7d082.js"></script>

<p>Above, we globally find a lastname element with a value of �Hewitt', then grab the parent node of
    lastname which happens to be the player node, then grab the id attribute from the player node.
    Alternatively, you could get the same result from the following simpler statement:</p>

<script src="https://gist.github.com/codenameone/66f32c76228dd494f2c1.js"></script>

<p>It is also possible to nest expressions, for example:</p>

<script src="https://gist.github.com/codenameone/1c02a6178b6004923c36.js"></script>

<p>In the above example, if the player node had an address object, we'd be selecting all players from Canada.
    This is a simple example of a nested expression, but they can get much more complex, which will be
    required as the documents themselves get more complex.<br/> Moving on, to select a node based
    on the existence of an attribute:</p>

<script src="https://gist.github.com/codenameone/1ecccc99a5870508ee9c.js"></script>

<p>Above, we selected the IDs of all ranked players.  Conversely, we can select the non-ranked players like this:</p>

<script src="https://gist.github.com/codenameone/c3b8bf065f75450a6494.js"></script>

<p>(Logical not (!) operators currently are not implemented).<br/>You can also select by the existence
    of a child node.</p>

<script src="https://gist.github.com/codenameone/3bdfd6be2cf62af5becd.js"></script>
<p> Above, we selected all players that have a middle name.<br/>
        Keep in mind that the Codename One path expression language is not a full implementation of
        XPath 1.0, but does already handle many of the most useful features of the specification. </p>

Package com.codename1.rad.processing

Package com.codename1.rad.processing Description