Offer Pure Java Interception Scripts

[nynymike]

Instead of using a script, the end user should be able to specify a Java class and upload a third party jar file to the lib folder.

[yuriyz]

Pure Java support is added.

During implementation I noticed that loading already compiled class produce few inconveniences to author of the script:

• how do I compile it? (author have to switch to jans-auth-server classpath and manage class path on their own)
• how do I pack it into jar? (e.g. do I need specific package to put it in?)
• given these extra steps isn't it easier to use jython?

To make it easier for end-author of the script pure java support works in same as jython:

• write java code (put it via UI or jans-config-api)
• AS will compile it and run. No need to compile and pack it manually.
• loading from file is supported in the same way as for Jython (simply put it in java source file and specify location, e.g. /opt/jans/jetty/jans-auth/custom/scripts/Discovery.java).

Docs:
https://github.com/JanssenProject/jans/wiki/Interception-scripts--(or--Custom-scripts)#using-pure-java-scripts

Sample script:

import io.jans.model.SimpleCustomProperty;
import io.jans.model.custom.script.model.CustomScript;
import io.jans.model.custom.script.type.discovery.DiscoveryType;
import io.jans.service.custom.script.CustomScriptManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.json.JSONObject;

import java.util.Map;

/**
 * @author Yuriy Zabrovarnyy
 */
public class Discovery implements DiscoveryType {

    private static final Logger log = LoggerFactory.getLogger(Discovery.class);
    private static final Logger scriptLogger = LoggerFactory.getLogger(CustomScriptManager.class);

    @Override
    public boolean init(Map<String, SimpleCustomProperty> configurationAttributes) {
        log.info("Init of Discovery Java custom script");
        return true;
    }

    @Override
    public boolean init(CustomScript customScript, Map<String, SimpleCustomProperty> configurationAttributes) {
        log.info("Init of Discovery Java custom script");
        return true;
    }

    @Override
    public boolean destroy(Map<String, SimpleCustomProperty> configurationAttributes) {
        log.info("Destroy of Discovery Java custom script");
        return true;
    }

    @Override
    public int getApiVersion() {
        log.info("getApiVersion Discovery Java custom script: 11");
        return 11;
    }

    @Override
    public boolean modifyResponse(Object responseAsJsonObject, Object context) {
        scriptLogger.info("write to script logger");
        JSONObject response = (JSONObject) responseAsJsonObject;
        response.accumulate("key_from_java", "value_from_script_on_java");
        return true;
    }
}