Author: jens
Date: Sun Feb 10 20:36:56 2013
New Revision: 1444605
URL: http://svn.apache.org/r1444605
Log:
QueryParser sample: add a read me text file.
Added:
chemistry/opencmis/trunk/chemistry-opencmis-samples/chemistry-opencmis-queryparser/readme.txt
Added:
chemistry/opencmis/trunk/chemistry-opencmis-samples/chemistry-opencmis-queryparser/readme.txt
URL:
http://svn.apache.org/viewvc/chemistry/opencmis/trunk/chemistry-opencmis-samples/chemistry-opencmis-queryparser/readme.txt?rev=1444605&view=auto
==============================================================================
---
chemistry/opencmis/trunk/chemistry-opencmis-samples/chemistry-opencmis-queryparser/readme.txt
(added)
+++
chemistry/opencmis/trunk/chemistry-opencmis-samples/chemistry-opencmis-queryparser/readme.txt
Sun Feb 10 20:36:56 2013
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+Readme.txt chemistry-opencmis-queryparser-example
+=================================================
+
+This project is an example how to build a query parser using the OpenCMIS
query framework.
+
+The example is standalone program that makes use of the AntLR based query
parser. It
+parses a CMIS query string and creates after traversing the syntax tree a new
statement in
+CMIS query language. While this sounds pretty useless this sample still has
value:
+ - it is not dependent on any query language of a backend (like a database) or
a
+ specific database scheme.
+ - it can be easily adapted to generate output in different format (SQL, XML,
JSON)
+ - it separates classes that can be reused from those that are specific to the
output
+ language
+ - it provides unit tests that can be adapted to other target languages.
+
+The sample provides code for the full cycle to parse and process a query. The
entry point
+is a static main() method so that it runs standalone without any server.
Usually this code
+will be called from the CMIS Discovery service in a real CMIS server.
+
+The code consists of the following classes:
+
+ExampleQueryProcessor.java:
+This is the main class. It takes a query and parses it. It traverses the
generated tree
+and finally builds the output.
+
+ExampleQueryWalker.java:
+A walker that traverses the syntax tree and generates the CMISQL output. For
each node in
+the tree callback functions are provided processing a specific token.
+
+ExampleTypeManager.java:
+An OpenCMIS parser processes the query and does certain checks for validity.
To do this
+it needs information about the available types and properties in the backend.
This
+information is provided by the interface TypeManager. This class implements a
minimal
+type system to get a running sample. It has only one type implemented:
cmis:document
+(note that this is not allowed for a real server according to the CMIS spec).
+
+ExtendedAbstractPredicateWalker.java
+This class extends the predefined walker from the server support package. It
provides
+more fine grained control and more hooks to plugin while traversing the tree.
This part
+is independent of the generated output and therefore separated in its own
class. It may
+be reused for other projects.
+
+ExampleQueryProcessorTest.java
+A Junit test that feeds the parser with CMISQL queries and compares the
generated output
+against an expected result. While the tests are specific to the output
language the basic
+principles and design of the unit test can be done in the same way for other
parsers.
+
+
+
