wardle / hermes-api

hermes-api

This defines the Java API interfaces for hermes, making it easier to use hermes from Java, or other JVM languages.

This library is not designed to be referenced directly by client applications. It is actually a dependency of the main hermes library and so will be included in your project as a transitive dependency when you use hermes.

DO NOT specify hermes-api in your pom.xml.

Therefore, users interested in using hermes from Java, or another JVM hosted language should simply use the hermes library jar directly from their build tool.

For example, here is how I use this from a Java application using maven:

<dependency>
  <groupId>com.eldrix</groupId>
  <artifactId>hermes</artifactId>
  <version>*******</version>
</dependency>

You will want to double check that you are using the latest version.

As the hermes library jar is published to the Clojars repository, you may need to explicitly reference that repository in your build configuration:

<repositories>
    <repository>
        <id>clojars.org</id>
        <url>https://clojars.org/repo</url>
    </repository>
</repositories>

To use hermes from Java, or another JVM hosted language, you primarily use the class com.eldrix.hermes.client.Hermes.

You should be able to work out how to use it from the source code.

Developer documentation

To publish the latest version of this library to sonatype, run

mvn clean deploy

For this to work successfully, you will need the appropriate credentials. Make sure you have a valid .m2/settings.xml file:

<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>wardle</username>
      <password>*******</password>
    </server>
  </servers>
</settings>

Make sure you have a valid GPG key and it is uploaded to a public key server. e.g.

gpg --gen-key
gpg --list-keys
gpg --keyserver keyserver.ubuntu.com --send-keys XXXXXXX

hermes-api's Issues

[FEATURE] add method to validate expression without expanding it

There is a method to expand expressions that, if the expression is wrong, throws an exception from the expression parser.

In our implementation we allow users to prevalidate expressions, before actually expanding them, which happens when a data query is e valuated, so we can grant expressions used in queries are actually valid.

We can use the same service for the expansion to actually validate the expression, and if there is an exception, then the expression is not valid. Though when the expression is valid, all the expansion work will happen, which is less performant than just parsing the expression. Also, all codes from the expansion are just discarded, because we care only about the expression validity, not the actual expansion.

It would be useful to have an isValid(String expression): boolean method in the API to support this use case, which internally avoids all the expansion processing and just does the parsing.

Thanks!