Drools cannot find the compiler when I try to load a Decision Table

Question

I work on a program which its integrate an engine rule, build with Drools. At the startup of my program I load spreadsheet files with Drools and everything is fine. My class constructor :

public DecisionTable(ApplicationServiceImpl applicationServiceImpl, DecisionTableInputType decisionTableInputType) {

    this.applicationServiceImpl = applicationServiceImpl;

    if (this.applicationServiceImpl.getDecisionTableConfiguration() == null) {
   this.applicationServiceImpl.setDecisionTableConfiguration(KnowledgeBuilderFactory.newDecisionTableConfiguration());
    }

    this.applicationServiceImpl.getDecisionTableConfiguration().setInputType(decisionTableInputType);

    knowledgeBuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
}

But later in my program, users can upload a file with a primefaces UI, and then I have several exception throw. When I debug step by step my code I go down to class org.drools.compiler.rule.builder.dialect.java.JavaDialectConfiguration on the method "setCompiler" I have the following RuntimeException : "The Eclipse JDT Core jar is not in the classpath" which is throw by a ClassNotFoundException.

public void setCompiler(final CompilerType compiler) {
    // check that the jar for the specified compiler are present
    if ( compiler == CompilerType.ECLIPSE ) {
        try {
            Class.forName( "org.eclipse.jdt.internal.compiler.Compiler", true, this.conf.getClassLoader() );
        } catch ( ClassNotFoundException e ) {
            throw new RuntimeException( "The Eclipse JDT Core jar is not in the classpath" );
        }
    } else if ( compiler == CompilerType.JANINO ){
        try {
            Class.forName( "org.codehaus.janino.Parser", true, this.conf.getClassLoader() );
        } catch ( ClassNotFoundException e ) {
            throw new RuntimeException( "The Janino jar is not in the classpath" );
        }
    }

    switch ( compiler ) {
        case ECLIPSE :
            this.compiler = CompilerType.ECLIPSE;
            break;
        case JANINO :
            this.compiler = CompilerType.JANINO;
            break;
        case NATIVE :
            this.compiler = CompilerType.NATIVE;
            break;
        default :
            throw new RuntimeException( "value '" + compiler + "' is not a valid compiler" );
    }
}

That exception is only throw when I try to load a file after my program has been start. At the startup I do not have exceptions, the setCompiler method is correctly runs. I cannot find the difference, my DecisionTable class is called by the same ApplicationServiceImpl at startup and when I run my code.

Some says the Eclipse JDT Core is missing, but if it is missing, why the program runs correctly at startup ? The engine rule with Drools runs correctly and my engine rules works correctly.

I use primefaces 6, Java JDK 1.7, and I use the Drools following version :

<dependency>
   <groupId>org.kie</groupId>
   <artifactId>kie-ci</artifactId>
   <version>7.28.0.Final</version>
</dependency>
<dependency>
   <groupId>org.drools</groupId>
   <artifactId>drools-decisiontables</artifactId>
   <version>7.28.0.Final</version>
</dependency>

You don't need a compiler to _run_ the program. Once you tell it to use eclipse, it tries to hook it up and realized it's missing. Just add the eclipse jar to your classpath and you should be fine. — Roddy of the Frozen Peas, Dec 25 '19 at 14:10
BUt can I not add the eclipse jar ? I don't want to integrate the eclipse jar in my project, but can it be possible ? — Fred37b, Jan 06 '20 at 13:26
Then include the janino compiler instead and configure Drools to use janino instead of eclipse. — Roddy of the Frozen Peas, Jan 06 '20 at 13:45

Drools cannot find the compiler when I try to load a Decision Table

0 Answers0