slf4j-api/src/test/java/org/slf4j/helpers/SubstitutableLoggerTest.java

/**
 * Copyright (c) 2004-2011 QOS.ch
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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package org.slf4j.helpers;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import junit.framework.TestCase;
import org.slf4j.Logger;

/**
 * @author Chetan Mehrotra
 */
public class SubstitutableLoggerTest extends TestCase {
  private static final Set<String> EXCLUDED_METHODS = new HashSet<String>(Arrays.asList("getName"));

  public void testDelegate() throws Exception {
    SubstituteLogger log = new SubstituteLogger("foo");
    assertTrue(log.delegate() instanceof NOPLogger);

    Set<String> expectedMethodSignatures = determineMethodSignatures(Logger.class);
    LoggerInvocationHandler ih = new LoggerInvocationHandler();
    Logger proxyLogger = (Logger) Proxy.newProxyInstance(getClass().getClassLoader(),
        new Class[]{Logger.class}, ih);
    log.setDelegate(proxyLogger);

    invokeMethods(log);

    //Assert that all methods are delegated
    expectedMethodSignatures.removeAll(ih.getInvokedMethodSignatures());
    if (!expectedMethodSignatures.isEmpty()) {
      fail("Following methods are not delegated " + expectedMethodSignatures.toString());
    }
  }

  private void invokeMethods(Logger proxyLogger) throws InvocationTargetException, IllegalAccessException {
    for (Method m : Logger.class.getDeclaredMethods()) {
      if (!EXCLUDED_METHODS.contains(m.getName())) {
        m.invoke(proxyLogger, new Object[m.getParameterTypes().length]);
      }
    }
  }

  private class LoggerInvocationHandler implements InvocationHandler {
    private final Set<String> invokedMethodSignatures = new HashSet<String>();

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
      invokedMethodSignatures.add(getMethodSignature(method));
      if (method.getName().startsWith("is")) {
        return true;
      }
      return null;
    }

    public Set<String> getInvokedMethodSignatures() {
      return invokedMethodSignatures;
    }
  }

  private static Set<String> determineMethodSignatures(Class<Logger> loggerClass) {
    Set<String> methodSignatures = new HashSet<String>();
    for (Method m : loggerClass.getDeclaredMethods()) {
      if (!EXCLUDED_METHODS.contains(m.getName())) {
        methodSignatures.add(getMethodSignature(m));
      }
    }
    return methodSignatures;
  }

  private static String getMethodSignature(Method m) {
    List<String> result = new ArrayList<String>();
    result.add(m.getName());
    for (Class<?> clazz : m.getParameterTypes()) {
      result.add(clazz.getSimpleName());
    }
    return result.toString();
  }
}