At 18:33 18.04.2001 +0200, Anders Kristensen wrote:
>Hey Ceki,
>
>I have a similar test program which shows the String setter being
>preferred over the long setter. Turns out that the JavaBeans
>introspector (at least the JDK 1.3 one) reports properties of different
>types (and with different setter/getter method) depending on which
>setter (maybe getter also) is defined first in the .java source file!
>Relying on the order of methods doesn't seem like a good recipe for
>maintainable software.
This is truly quite amazing. Saying "our code broke because the order of method
definitions changed" will not earn us any brownie points to say the least.
>I wonder if ideally we should have a custom introspector rather than
>adding custom BeanInfo classes per log4j component as the latter adds
>per-component overhead and people writing their own components may
>easily get it wrong. For getting v1.1 out the door quickly we might
>still just add the custom BeanInfo to RollingFileAppender.
A custom introspector? How would a custom introspector solve the problem at hand? What
do you have in mind?
A custom bean info is only needed for the RollingFileAppender. I am not aware of any
other appender or layout defining differently typed setters or getters for a given
JavaBeans property.
BTW, this was cute little exercise... Cheers, Ceki
ps: I am about to release 1.1b3 that adds RollingFileAppenderBeanInfo thus correcting
the backward compatibility issue as outlined in my previous mail.
>Anders
>
>
>Ceki Gülcü wrote:
>>
>> Hi Anders,
>>
>> Here is a small test program:
>>
>> import org.apache.log4j.*;
>> import org.apache.log4j.config.*;
>> import java.beans.*;
>>
>> public class R {
>>
>> static public void main(String[] args) {
>> try {
>> BeanInfo bi = Introspector.getBeanInfo(RollingFileAppender.class);
>> PropertyDescriptor[] props = bi.getPropertyDescriptors();
>> for(int i = 0; i < props.length; i++) {
>> System.out.println("Property name: "+ props[i].getName()+
>> ", type: "+props[i].getPropertyType());
>>
>> System.out.println("Setter method: "+ props[i].getWriteMethod()+"\n")
>> }
>> } catch(Exception e) {
>> e.printStackTrace();
>> }
>> }
>> }
>>
>> It spits out:
>>
>> Property name: name, type: class java.lang.String
>> Setter method: public void
>org.apache.log4j.AppenderSkeleton.setName(java.lang.String)
>>
>> Property name: maxBackupIndex, type: int
>> Setter method: public void
>org.apache.log4j.RollingFileAppender.setMaxBackupIndex(int)
>>
>> Property name: filter, type: class org.apache.log4j.spi.Filter
>> Setter method: null
>>
>> Property name: append, type: boolean
>> Setter method: public void org.apache.log4j.FileAppender.setAppend(boolean)
>>
>> Property name: file, type: class java.lang.String
>> Setter method: public void org.apache.log4j.FileAppender.setFile(java.lang.String)
>>
>> Property name: maxFileSize, type: long <---- Note this
>> Setter method: public void
>org.apache.log4j.RollingFileAppender.setMaxFileSize(long) <--- and this
>>
>> Property name: writer, type: class java.io.Writer
>> Setter method: public synchronized void
>org.apache.log4j.WriterAppender.setWriter(java.io.Writer)
>>
>> Property name: class, type: class java.lang.Class
>> Setter method: null
>>
>> Property name: firstFilter, type: class org.apache.log4j.spi.Filter
>> Setter method: null
>>
>> Property name: threshold, type: class org.apache.log4j.Priority
>> Setter method: public void
>org.apache.log4j.AppenderSkeleton.setThreshold(org.apache.log4j.Priority)
>>
>> Property name: errorHandler, type: interface org.apache.log4j.spi.ErrorHandler
>> Setter method: public synchronized void
>org.apache.log4j.WriterAppender.setErrorHandler(org.apache.log4j.spi.ErrorHandler)
>>
>> Property name: layout, type: class org.apache.log4j.Layout
>> Setter method: public void
>org.apache.log4j.AppenderSkeleton.setLayout(org.apache.log4j.Layout)
>>
>> Property name: immediateFlush, type: boolean
>> Setter method: public void
>org.apache.log4j.WriterAppender.setImmediateFlush(boolean)
>>
>> Property name: optionStrings, type: class [Ljava.lang.String;
>>
>> (This, when the setMaxFileSize(long) in RollingFileAppender is put back in.)
>>
>> I am using
>>
>> java version "1.3.0"
>> Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
>> Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)
>>
>> on Windows 2000.
>>
>> In any case, the setMaxFileSize(String) setter is invisible. I suppose the rest of
>the problem is clear. The wrong settter method is used for the maxFileSize property
>which causes a NumberFormatException, etc, etc.
>>
>> The only solution I can think of apart from removing setMaxFileSize(long), is to
>write a custom RollingFileAppenderBeanInfo class to circumvent the problem... Cheers,
>Ceki
>>
>> At 04:57 19.04.2001 +0200, Anders Kristensen wrote:
>> >Actually it seems that the JavaBeans introspector returns the String
>> >setter when a class has something like
>> >
>> > setMaxFileSize(long)
>> > setMaxFileSize(String)
>> >
>> >so I don't know why setMaxFileSize(long) had to be commented out?
>> >
>> >Cheers,
>> >Anders
>> >
>> >
>> >Ceki Gülcü wrote:
>> >>
>> >> Aaaaaaaaaaaaah!
>> >>
>> >> There are two versions of setMaxFileSize in RollingFileAppender:
>> >>
>> >> setMaxFileSize(long)
>> >>
>> >> and
>> >>
>> >> setMaxFileSize(String)
>> >>
>> >> The problem is that the JabaBeans Introspector returns the former when asked for
>setter methods in RollingFileAppender. However, this causes problems when log4j is
>configured using scripts because the
>> >> max file size is specified using units as in 1048576, 1024KB, or 1MB but 1MB is
>not a valid number calling setMaxFileSize(long) fails.
>> >>
>> >> The only solution I can think of is to add a custom BeanInfo class for
>RollingFileAppender where the setMaxFileSize(long) setter is removed. This is a bit
>cumbersome but can be done.
>> >>
>> >> Well, I never imagined that someone was using the removed method. I guess I was
>wrong. I'll see what I can do.
>> >>
>> >> Anders, do you have a better idea? Cheers, Ceki
>> >>
>> >> ps: Sam, thanks for the info.
>> >>
>> >> At 05:32 18.04.2001 -0400, Sam Ruby wrote:
>> >> >Why was setMaxFileSize(long) in org.apache.log4j.RollingFileAppender removed?
>> >> >
>> >>
>>http://jakarta.apache.org/cvsweb/index.cgi/jakarta-log4j/src/java/org/apache/log4j/RollingFileAppender.java.diff?r1=1.8&r2=1.9&diff_format=h
>> >> >
>> >> >In a few hours, you should be able to see the failure that this produces at:
>> >> >
>> >> >http://jakarta.apache.org/builds/gump/2001-04-18/jakarta-velocity.html
>> >> >
>> >> >- Sam Ruby
>> >> >
>> >> >
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>> >> Ceki Gülcü
>> >>
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>> --
>> Ceki Gülcü
>>
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