package org.hibernate.tool.instrument.javassist;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import javassist.bytecode.ClassFile;
import org.hibernate.tool.instrument.BasicInstrumentationTask;
import org.hibernate.bytecode.util.ClassDescriptor;
import org.hibernate.bytecode.util.BasicClassFilter;
import org.hibernate.bytecode.ClassTransformer;
import org.hibernate.bytecode.javassist.BytecodeProviderImpl;
import org.hibernate.bytecode.javassist.FieldHandled;
/**
* An Ant task for instrumenting persistent classes in order to enable
* field-level interception using Javassist.
* <p/>
* In order to use this task, typically you would define a a taskdef
* similiar to:<pre>
* <taskdef name="instrument" classname="org.hibernate.tool.instrument.javassist.InstrumentTask">
* <classpath refid="lib.class.path"/>
* </taskdef>
* </pre>
* where <tt>lib.class.path</tt> is an ANT path reference containing all the
* required Hibernate and Javassist libraries.
* <p/>
* And then use it like:<pre>
* <instrument verbose="true">
* <fileset dir="${testclasses.dir}/org/hibernate/test">
* <include name="yadda/yadda/**"/>
* ...
* </fileset>
* </instrument>
* </pre>
* where the nested ANT fileset includes the class you would like to have
* instrumented.
* <p/>
* Optionally you can chose to enable "Extended Instrumentation" if desired
* by specifying the extended attriubute on the task:<pre>
* <instrument verbose="true" extended="true">
* ...
* </instrument>
* </pre>
* See the Hibernate manual regarding this option.
*
* @author Muga Nishizawa
* @author Steve Ebersole
*/
public class InstrumentTask extends BasicInstrumentationTask {
private static final BasicClassFilter CLASS_FILTER = new BasicClassFilter();
private final BytecodeProviderImpl provider = new BytecodeProviderImpl();
protected ClassDescriptor getClassDescriptor(byte[] bytecode) throws IOException {
return new CustomClassDescriptor( bytecode );
}
protected ClassTransformer getClassTransformer(ClassDescriptor descriptor) {
if ( descriptor.isInstrumented() ) {
logger.verbose( "class [" + descriptor.getName() + "] already instrumented" );
return null;
}
else {
return provider.getTransformer( CLASS_FILTER, new CustomFieldFilter( descriptor ) );
}
}
private static class CustomClassDescriptor implements ClassDescriptor {
private final byte[] bytes;
private final ClassFile classFile;
public CustomClassDescriptor(byte[] bytes) throws IOException {
this.bytes = bytes;
this.classFile = new ClassFile( new DataInputStream( new ByteArrayInputStream( bytes ) ) );
}
public String getName() {
return classFile.getName();
}
public boolean isInstrumented() {
String[] intfs = classFile.getInterfaces();
for ( int i = 0; i < intfs.length; i++ ) {
if ( FieldHandled.class.getName().equals( intfs[i] ) ) {
return true;
}
}
return false;
}
public byte[] getBytes() {
return bytes;
}
}
}
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