Support for Filter method String.contains().

[hopecee]

Hi!
We already have the following Filter methods,
.eq() => equals to
.ne() => not equal to
.startsWith() => begins with
.matches() => exact value

Can we have method to search for string which contains a string value?
For instance, if a string like Appletogether, searching for toget is true.

I have not seen the method for that.

[andyjefferson]

If you want a feature adding you need to fork the code and contribute the feature via a GitHub pull request.

[hopecee]

I need to learn that now. You can put me through. To do this I need to fork both datanucleus-neo4j and datanucleus-core.

[andyjefferson]

FYI Valid JDOQL methods are shown on this link http://www.datanucleus.org:15080/products/accessplatform_5_1/jdo/query.html#jdoql_methods
No idea why you would need to fork datanucleus-core, because that then affects ALL datastores. The only possible addition to datanucleus-core would be to add the METHOD "contains" for String values, since JAVA has a method String.contains(...).

[hopecee]

If the String.contains() is added it will help.

This Cypher code can be used to check for the String that contains a variable value;

MATCH (p:Person)
WHERE p.name =~ '.*Apple.*'
RETURN p

OR

MATCH (p:Person)
WHERE p.name =~ '(?i).*apple.*' //case-insensitive
RETURN p

I have trying to look for how to add the method by adding code to these files;
9ed0bce
7faeb30
11a5a40

5d09a07

I am still looking and studying for where the actual method is added so that I can test it.
To add the method some files have to be modified , like;
https://github.com/datanucleus/datanucleus-api-jdo/blob/master/src/main/java/org/datanucleus/api/jdo/query/ExpressionImpl.java

[andyjefferson]

The JDOQL is
stringField.contains(someValue)

which maps on to a generic compilation of InvokeExpression. InvokeExpression is what you should process in the neo4j plugin. i.e in QueryToCypherMapper.java

[hopecee]

Sorry, Please how do I get that?
I have opened the file and trying to wrap my head on what to do here.
https://github.com/datanucleus/datanucleus-neo4j/blob/master/src/main/java/org/datanucleus/store/neo4j/query/QueryToCypherMapper.java

[andyjefferson]

processInvokeExpression in that class I just quoted! just look at other plugins that do querying, and they all handle methods

[hopecee]

I am having small issue on how to release on GitHub. The Zip file doesn't look like the normal jar file.
I need to know how to bring out the jar file so I can test the changes.

[andyjefferson]

No idea what that means. To contribute on GitHub you provide a PULL REQUEST, via the Pull Requests option on the project.

[hopecee]

I will make PULL REQUEST, but wont it be to test the commit before making PULL REQUEST?
I am learning.

[andyjefferson]

It is for YOU to test the proposed changes, before submitting the PULL REQUEST. Hence it is in your local codebase, so you test it locally

[hopecee]

Yes I test it locally. Shouldn't I extract the jar and run it on my IDE? Or is there any way to test it on GitHub?

[andyjefferson]

GitHub is a repository. It doesn't test anything. You test it. There are some simply tests under the repository "tests", navigating to "jdo/neo4j", as per what the documentation says.

Also, to correct your earlier statement, there is no "startsWith" or "matches" supported by this plugin, as you can see from the processInvokeExpression method. No methods are currently supported.

[andyjefferson]

To give an idea of how methods can be added (and since we didnt support any on this plugin before) I've added support for String toUpperCase/toLowerCase in issue #38 . Use the code added there as a guide to adding "contains" support for String fields