LoggingInterceptor.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License, version 2 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/gpl-2.0.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 */
package org.pentaho.platform.engine.security;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

import org.apache.commons.lang.builder.ReflectionToStringBuilder;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.platform.engine.security.messages.Messages;
import org.springframework.aop.AfterReturningAdvice;
import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.ThrowsAdvice;

/**
 * Logger that uses AOP to log debugging information.
 *
 * <p><strong>Do not use this in production! It logs passwords in plain text!</strong></p>
 * @author mlowery
 */
public class LoggingInterceptor implements MethodBeforeAdvice, AfterReturningAdvice, ThrowsAdvice {

  public void before(final Method method, final Object[] args, final Object target) throws Throwable {
    Log logger = LogFactory.getLog(target.getClass());
    if (logger.isDebugEnabled()) {
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_BEGIN_METHOD")); //$NON-NLS-1$
      log(method, args, target);
    }
  }

  public void afterReturning(final Object returnValue, final Method method, final Object[] args, final Object target)
      throws Throwable {
    Log logger = LogFactory.getLog(target.getClass());
    if (logger.isDebugEnabled()) {
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_END_METHOD")); //$NON-NLS-1$
      log(method, args, target);
      logger.debug(Messages.getInstance().getString(
          "LoggingInterceptor.DEBUG_RETURN_VALUE", returnValue.getClass().getName(), toString(returnValue))); //$NON-NLS-1$
    }
  }

  public void afterThrowing(final Method method, final Object[] args, final Object target, final Throwable exception) {
    Log logger = LogFactory.getLog(target.getClass());
    if (logger.isDebugEnabled()) {
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_EXCEPTION_IN_METHOD")); //$NON-NLS-1$
      log(method, args, target);
      logger.debug(Messages.getInstance().getString(
          "LoggingInterceptor.DEBUG_EXCEPTION", exception.getClass().getName(), exception.getMessage())); //$NON-NLS-1$
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_STACK_TRACE"), exception); //$NON-NLS-1$
    }
  }

  private void log(final Method method, final Object[] args, final Object target) {
    Log logger = LogFactory.getLog(target.getClass());
    if (logger.isDebugEnabled()) {
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_METHOD_NAME", method.getName())); //$NON-NLS-1$
      logger.debug(Messages.getInstance().getString(
          "LoggingInterceptor.DEBUG_TARGET_OBJECT", target.getClass().getName(), toString(target))); //$NON-NLS-1$
      logger.debug(Messages.getInstance().getString("LoggingInterceptor.DEBUG_METHOD_ARGS", arrayToString(args))); //$NON-NLS-1$
    }
  }

  /**
   * Returns a string representation of the given object. This is useful when third-party objects do not have
   * <code>toString()</code> implementations that meet your needs.
   */
  protected String toString(final Object object) {
    /**
     * This impl uses reflection to print fields and it also skips sensitive fields.
     */
    return (new ReflectionToStringBuilder(object) {
      @Override
      protected boolean accept(final Field f) {
        return super.accept(f) && !f.getName().equals("password") && !f.getName().equals("credentials"); //$NON-NLS-1$ //$NON-NLS-2$
      }
    }).toString();
  }

  /**
   * Returns a string representation of the given array. Instead of overriding this method, try overriding
   * <code>toString(object)</code> instead.
   */
  protected String arrayToString(final Object[] objects) {
    StringBuffer buf = new StringBuffer();
    if (null == objects) {
      return "null"; //$NON-NLS-1$
    } else {
      for (int i = 0; i < objects.length; i++) {
        if (i > 0) {
          buf.append(", "); //$NON-NLS-1$
        }
        buf.append(toString(objects[i]));
      }
      return buf.toString();
    }
  }

}