Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.boolex;

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.boolex.EvaluationException;
import ch.qos.logback.core.boolex.EventEvaluatorBase;
import ch.qos.logback.core.util.FileUtil;
import groovy.lang.*;
import org.codehaus.groovy.control.CompilationFailedException;

Author:
Ceki Gülcü/**
 * @author Ceki Gülcü
 */
public class GEventEvaluator extends EventEvaluatorBase<ILoggingEvent> {

    String expression;

    IEvaluator delegateEvaluator;
    Script script;

    public String getExpression() {
        return expression;
    }

    public void setExpression(String expression) {
        this.expression = expression;
    }

    public void start() {
        int errors = 0;
        if (expression == null || expression.length() == 0) {
            addError("Empty expression");
            return;
        } else {
            addInfo("Expression to evaluate [" + expression + "]");
        }

        ClassLoader classLoader = getClass().getClassLoader();
        String currentPackageName = this.getClass().getPackage().getName();
        currentPackageName = currentPackageName.replace('.', '/');

        FileUtil fileUtil = new FileUtil(getContext());
        String scriptText = fileUtil.resourceAsString(classLoader, currentPackageName + "/EvaluatorTemplate.groovy");
        if (scriptText == null) {
            return;
        }

        // insert the expression into script text
        scriptText = scriptText.replace("//EXPRESSION", expression);

        GroovyClassLoader gLoader = new GroovyClassLoader(classLoader);
        try {
            Class scriptClass = gLoader.parseClass(scriptText);

            GroovyObject goo = (GroovyObject) scriptClass.newInstance();
            delegateEvaluator = (IEvaluator) goo;

        } catch (CompilationFailedException cfe) {
            addError("Failed to compile expression [" + expression + "]", cfe);
            errors++;
        } catch (Exception e) {
            addError("Failed to compile expression [" + expression + "]", e);
            errors++;
        }
        if (errors == 0)
            super.start();
    }

    public boolean evaluate(ILoggingEvent event) throws NullPointerException, EvaluationException {
        if (delegateEvaluator == null) {
            return false;
        }
        return delegateEvaluator.doEvaluate(event);
    }

}