Examples with ClassFileTransformer java.lang.instrument.ClassFileTransformer used on opensource projects

Example 56 with ClassFileTransformer

use of java.lang.instrument.ClassFileTransformer in project Payara by payara.

the class ASURLClassLoader method findClass.

/**
 * THREAD SAFETY: what happens when more than one thread requests the same class
 *        and thus works on the same classData?  Or defines the same package?  Maybe
 *        the same work just gets done twice, and that's all.
 *        CAUTION: this method might be overriden, and subclasses must be cautious (also)
 *        about thread safety.
 */
protected Class findClass(String name) throws ClassNotFoundException {
    ClassData classData = findClassData(name);
    // Instruments the classes if the profiler's enabled
    if (PreprocessorUtil.isPreprocessorEnabled()) {
        // search thru the JARs for a file of the form java/lang/Object.class
        final String entryName = name.replace('.', '/') + ".class";
        classData.setClassBytes(PreprocessorUtil.processClass(entryName, classData.getClassBytes()));
    }
    // Define package information if necessary
    int lastPackageSep = name.lastIndexOf('.');
    if (lastPackageSep != -1) {
        String packageName = name.substring(0, lastPackageSep);
        if (getPackage(packageName) == null) {
            try {
                // There's a small chance that one of our parents
                // could define the same package after getPackage
                // returns null but before we call definePackage,
                // since the parent classloader instances
                // are not locked.  So, just catch the exception
                // that is thrown in that case and ignore it.
                // 
                // It's unclear where we would get the info to
                // set all spec and impl data for the package,
                // so just use null.  This is consistent will the
                // JDK code that does the same.
                definePackage(packageName, null, null, null, null, null, null, null);
            } catch (IllegalArgumentException iae) {
                // duplicate attempt to define same package.
                // safe to ignore.
                _logger.log(Level.FINE, "duplicate package " + "definition attempt for " + packageName, iae);
            }
        }
    }
    // Loop though the transformers here!!
    try {
        final ArrayList<ClassFileTransformer> xformers = (ArrayList<ClassFileTransformer>) transformers.clone();
        for (final ClassFileTransformer transformer : xformers) {
            // see javadocs of transform().
            // It expects class name as java/lang/Object
            // as opposed to java.lang.Object
            final String internalClassName = name.replace('.', '/');
            final byte[] transformedBytes = transformer.transform(this, internalClassName, null, classData.pd, classData.getClassBytes());
            if (transformedBytes != null) {
                // null indicates no transformation
                _logger.log(Level.INFO, CULoggerInfo.actuallyTransformed, name);
                classData.setClassBytes(transformedBytes);
            }
        }
    } catch (IllegalClassFormatException icfEx) {
        throw new ClassNotFoundException(icfEx.toString(), icfEx);
    }
    Class clazz = null;
    try {
        byte[] bytes = classData.getClassBytes();
        clazz = defineClass(name, bytes, 0, bytes.length, classData.pd);
        return clazz;
    } catch (UnsupportedClassVersionError ucve) {
        throw new UnsupportedClassVersionError(sm.getString("ejbClassLoader.unsupportedVersion", name, System.getProperty("java.version")));
    }
}