Problem with using classes from different modules
Hello,
I have been playing around with JCC to see if it would provide in the
needs we have here at work to interface Java with Python. I have
encountered one issue in which I hope someone on this mailinglist might
be able to help me with. If this is not the right place to ask then I
apologize in advance.
This issue I am having is that I would like to create two packages
compiled with JCC in which classes from one package are used by classes
in the other pacakge. I would like to use those classes in Python but am
having problems doing so that I don't understand yet.
In package 1 is the class shown below:
package nl.seecr.freestyle;
public class Sum {
private int _sum;
public Sum() {
_sum = 0;
}
public void add(int value) {
_sum += value;
}
public int value() {
return _sum;
}
}
The second package holds a class what uses the Sum Class:
package org.cq2.freestyle;
import nl.seecr.freestyle.Sum;
public class SumWrapper {
private Sum total;
public SumWrapper() {
this(new Sum());
System.out.println("Empty constructor");
}
public SumWrapper(Sum sum) {
total = sum;
}
public void add(int value) {
total.add(value);
}
public int value() {
return total.value();
}
public Sum asSum() {
Sum sum = new Sum();
sum.add(value());
return sum;
}
public void printValue() {
System.out.println(value());
}
}
I can compile these classes into .class files and put them in jars and
have those compiled with JCC:
python -m jcc \
--root ${ROOT} \
--use_full_names \
--shared \
--arch x86_64 \
--jar cq2.jar \
--classpath ./seecr.jar \
--python cq2 \
--build \
--install
export PYTHON_PATH=${ROOT}/usr/local/lib/python2.7/dist-packages
python -m jcc \
--root ${ROOT} \
--use_full_names \
--import cq2 \
--shared \
--arch x86_64 \
--jar seecr.jar \
--python seecr \
--build \
--install
In my understanding the "--import cq2" argument should prevent jcc from
creating a wrapper for the Sum class in the seecr package itself but use
the one in the cq2 package.
This all compiles without errors but when I run the following python
program:
import seecr
seecr.initVM()
import cq2
cq2.initVM()
from nl.seecr.freestyle import Sum
from org.cq2.freestyle import SumWrapper
sum = Sum()
sum.add(5)
print "Sum value", sum.value()
wrapper = SumWrapper(sum)
print wrapper.value()
The 1st print shows the value 5 as expected. The 2nd print however shows
0 and I had not expected that. If I run the same program in Java and use
the jars I created earlier, the 2nd print shows 5 (as expected). The
"Empty constructor" message is also shown when running this python
program and I had not expected that to happen.
The "asSum" method in the SumWrapper class is not available in the
Python version of the class. I do not understand yet why that is.
I haven't been able to find many examples or documentation on the
options for compiling with JCC. I am hoping that someone here on the
mailinglist can point me in the right direction. Any help would be
really appreciated.
Johan
Re: [VOTE] Release PyLucene 4.3.1-1
On Sun, Jun 30, 2013 at 10:41 PM, Andi Vajda wrote: > And I have now reproduced the problem by forcing '/usr/bin/javac' to be the > one installed by Oracle's JDK 1.7, even though the original /usr/bin/javac > reported version 1.7.25. Sheesh, this is user hostile. > > Using Oracle's javac to compile Lucene causes the problem to reproduce. Phew, I'm glad you're able to reproduce, and it's spooky that compiling Lucene w/ Java7 causes what should be an AtomicReader to become an IndexReader... Mike McCandless http://blog.mikemccandless.com
[jira] [Created] (LUCENE-5086) RamUsageEstimator causes AWT classes to be loaded by calling ManagementFactory#getPlatformMBeanServer (fwd)
We're not alone :-) !
Andi..
-- Forwarded message --
Date: Mon, 1 Jul 2013 17:14:20 + (UTC)
From: "Shay Banon (JIRA)"
Reply-To: d...@lucene.apache.org
To: d...@lucene.apache.org
Subject: [jira] [Created] (LUCENE-5086) RamUsageEstimator causes AWT classes to
be loaded by calling ManagementFactory#getPlatformMBeanServer
Shay Banon created LUCENE-5086:
--
Summary: RamUsageEstimator causes AWT classes to be loaded by
calling ManagementFactory#getPlatformMBeanServer
Key: LUCENE-5086
URL: https://issues.apache.org/jira/browse/LUCENE-5086
Project: Lucene - Core
Issue Type: Bug
Reporter: Shay Banon
Yea, that type of day and that type of title :).
Since the last update of Java 6 on OS X, I started to see an annoying icon pop
up at the doc whenever running elasticsearch. By default, all of our scripts
add headless AWT flag so people will probably not encounter it, but, it was
strange that I saw it when before I didn't.
I started to dig around, and saw that when RamUsageEstimator was being loaded,
it was causing AWT classes to be loaded. Further investigation showed that
actually for some reason, calling ManagementFactory#getPlatformMBeanServer now
with the new Java version causes AWT classes to be loaded (at least on the mac,
haven't tested on other platforms yet).
There are several ways to try and solve it, for example, by identifying the bug
in the JVM itself, but I think that there should be a fix for it in Lucene
itself, specifically since there is no need to call #getPlatformMBeanServer to
get the hotspot diagnostics one (its a heavy call...).
Here is a simple call that will allow to get the hotspot mxbean without using
the #getPlatformMBeanServer method, and not causing it to be loaded and loading
all those nasty AWT classes:
[code]
Object getHotSpotMXBean() {
Object hotSpotBean = null;
try {
// Java 6
Class sunMF = Class.forName("sun.management.ManagementFactory");
return sunMF.getMethod("getDiagnosticMXBean").invoke(null);
} catch (Throwable t) {
// ignore
}
// potentially Java 7
try {
return ManagementFactory.class.getMethod("getPlatformMXBean",
Class.class).invoke(null, Class.forName("com.sun.management.HotSpotDiagnosticMXBean"));
} catch (Throwable t) {
// ignore
}
return null;
}
[/code]
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Re: Problem with using classes from different modules
On Mon, 1 Jul 2013, Johan Jonkers wrote:
Hello,
I have been playing around with JCC to see if it would provide in the needs
we have here at work to interface Java with Python. I have encountered one
issue in which I hope someone on this mailinglist might be able to help me
with. If this is not the right place to ask then I apologize in advance.
This issue I am having is that I would like to create two packages compiled
with JCC in which classes from one package are used by classes in the other
pacakge. I would like to use those classes in Python but am having problems
doing so that I don't understand yet.
In package 1 is the class shown below:
package nl.seecr.freestyle;
public class Sum {
private int _sum;
public Sum() {
_sum = 0;
}
public void add(int value) {
_sum += value;
}
public int value() {
return _sum;
}
}
The second package holds a class what uses the Sum Class:
package org.cq2.freestyle;
import nl.seecr.freestyle.Sum;
public class SumWrapper {
private Sum total;
public SumWrapper() {
this(new Sum());
System.out.println("Empty constructor");
}
public SumWrapper(Sum sum) {
total = sum;
}
public void add(int value) {
total.add(value);
}
public int value() {
return total.value();
}
public Sum asSum() {
Sum sum = new Sum();
sum.add(value());
return sum;
}
public void printValue() {
System.out.println(value());
}
}
I can compile these classes into .class files and put them in jars and have
those compiled with JCC:
python -m jcc \
--root ${ROOT} \
--use_full_names \
--shared \
--arch x86_64 \
--jar cq2.jar \
--classpath ./seecr.jar \
--python cq2 \
--build \
--install
export PYTHON_PATH=${ROOT}/usr/local/lib/python2.7/dist-packages
python -m jcc \
--root ${ROOT} \
--use_full_names \
--import cq2 \
--shared \
--arch x86_64 \
--jar seecr.jar \
--python seecr \
--build \
--install
In my understanding the "--import cq2" argument should prevent jcc from
creating a wrapper for the Sum class in the seecr package itself but use the
one in the cq2 package.
This all compiles without errors but when I run the following python program:
import seecr
seecr.initVM()
import cq2
cq2.initVM()
from nl.seecr.freestyle import Sum
from org.cq2.freestyle import SumWrapper
sum = Sum()
sum.add(5)
print "Sum value", sum.value()
wrapper = SumWrapper(sum)
print wrapper.value()
The 1st print shows the value 5 as expected. The 2nd print however shows 0
and I had not expected that. If I run the same program in Java and use the
jars I created earlier, the 2nd print shows 5 (as expected). The "Empty
constructor" message is also shown when running this python program and I had
not expected that to happen.
The "asSum" method in the SumWrapper class is not available in the Python
version of the class. I do not understand yet why that is.
I haven't been able to find many examples or documentation on the options for
compiling with JCC. I am hoping that someone here on the mailinglist can
point me in the right direction. Any help would be really appreciated.
I haven't had time yet to reproduce the problem but you may want to try to
add an explicit request to wrap the Sum class - by just listing it on the
second jcc call command line. No wrapper will be generated for it, because
of the --import statement, but methods in the second jar with Sum in their
signature should then get wrapped.
python -m jcc \
--root ${ROOT} \
--use_full_names \
--import cq2 \
--shared \
--arch x86_64 \
--jar seecr.jar \
--python seecr \
--build \
--install \
nl.seecr.freestyle.Sum
Andi..
