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https://issues.apache.org/jira/browse/OLINGO-118?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13873120#comment-13873120
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Michael Bolz commented on OLINGO-118:
-------------------------------------
??I want to be able to avoid running db queries to recreate the schema every
time an entry or feed is requested.??
IMHO if you want to use the {{ODataSingleProcessor}} (created via
{{ODataServiceFactory.createODataSingleProcessorService(..)}}) the best way to
avoid db queries (aka cache the metadata) is to cache the _schema_ within your
custom {{EdmProvider}} implementation (in the {{getSchema() method}}.
Because within the metadata read in the default {{ODataSingleProcessor}} the
_schema_ is get from the {{EdmProvider}} and then will be just serialized (for
deeper look into processing see {{EdmServiceMetadataImplProv.getMetadata()}}):
{code}
public InputStream getMetadata() throws ODataException {
if (schemas == null) {
schemas = edmProvider.getSchemas();
}
OutputStreamWriter writer = null;
CircleStreamBuffer csb = new CircleStreamBuffer();
EntityProviderException cachedException = null;
DataServices metadata = new
DataServices().setSchemas(schemas).setDataServiceVersion(getDataServiceVersion());
try {
writer = new OutputStreamWriter(csb.getOutputStream(), "UTF-8");
XMLStreamWriter xmlStreamWriter =
XMLOutputFactory.newInstance().createXMLStreamWriter(writer);
XmlMetadataProducer.writeMetadata(metadata, xmlStreamWriter, null);
return csb.getInputStream();
}
...
{code}
I hope this answers your question.
Kind regards,
Michael
> Typing of odata entry properties
> --------------------------------
>
> Key: OLINGO-118
> URL: https://issues.apache.org/jira/browse/OLINGO-118
> Project: Olingo
> Issue Type: Question
> Affects Versions: V2 1.1.0
> Reporter: M Carissimi
> Attachments: odata4j output.xml, olingo output.xml
>
>
> Hello,
> I am migrating an odata service from odata4j to olingo. During creation of
> single odata entries or odata feeds, odata4j allows you to specify the type
> of each property element. How can this be achieved in olingo? See attached
> xml feeds for an entry generated in odata4j and one generated in olingo.
> We generate the metadata at runtime using custom database queries and in
> odata4j we can cache the metadata document to avoid having to rebuild it
> every time a request is received. How can metadata be cached between requests
> in olingo? Following the simple read example on the olingo website, we use an
> ODataServiceFactory to create a service using method
> createODataSingleProcessorService(), but these methods are invoked during
> each request.
> Cheers
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