org.eclipse.sisu.space.SpaceScanner Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2010-present Sonatype, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Stuart McCulloch (Sonatype, Inc.) - initial API and implementation
*******************************************************************************/
package org.eclipse.sisu.space;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.net.URL;
import java.util.Enumeration;
import org.eclipse.sisu.inject.Logs;
import org.eclipse.sisu.space.asm.ClassReader;
import org.eclipse.sisu.space.asm.Opcodes;
import org.eclipse.sisu.space.asm.Type;
/**
* Makes a {@link SpaceVisitor} visit a {@link ClassSpace}; can be directed by an optional {@link ClassFinder}.
*/
public final class SpaceScanner
{
// ----------------------------------------------------------------------
// Constants
// ----------------------------------------------------------------------
private static final int ASM_FLAGS = ClassReader.SKIP_CODE | ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES;
static final ClassFinder DEFAULT_FINDER = new DefaultClassFinder();
// ----------------------------------------------------------------------
// Implementation fields
// ----------------------------------------------------------------------
private final ClassSpace space;
private final ClassFinder finder;
// ----------------------------------------------------------------------
// Constructors
// ----------------------------------------------------------------------
public SpaceScanner( final ClassSpace space, final ClassFinder finder )
{
this.space = space;
this.finder = finder;
}
public SpaceScanner( final ClassSpace space )
{
this( space, DEFAULT_FINDER );
}
// ----------------------------------------------------------------------
// Public methods
// ----------------------------------------------------------------------
/**
* Makes the given {@link SpaceVisitor} visit the {@link ClassSpace} of this scanner.
*
* @param visitor The class space visitor
*/
public void accept( final SpaceVisitor visitor )
{
visitor.enterSpace( space );
for ( final Enumeration result = finder.findClasses( space ); result.hasMoreElements(); )
{
final URL url = result.nextElement();
final ClassVisitor cv = visitor.visitClass( url );
if ( null != cv )
{
accept( cv, url );
}
}
visitor.leaveSpace();
}
/**
* Makes the given {@link ClassVisitor} visit the class contained in the resource {@link URL}.
*
* @param visitor The class space visitor
* @param url The class resource URL
*/
public static void accept( final ClassVisitor visitor, final URL url )
{
if ( null == url )
{
return; // nothing to visit
}
try
{
final InputStream in = Streams.open( url );
try
{
new ClassReader( in ).accept( adapt( visitor ), ASM_FLAGS );
}
finally
{
in.close();
}
}
catch ( final ArrayIndexOutOfBoundsException e ) // NOPMD
{
// ignore broken class constant pool in icu4j
}
catch ( final Exception e )
{
Logs.debug( "Problem scanning: {}", url, e );
}
}
/**
* Returns the JVM descriptor for the given annotation class, such as "Ljavax/inject/Qualifier;".
*
* @param clazz The annotation class
* @return JVM descriptor of the class
* @see ClassVisitor#visitAnnotation(String)
*/
public static String jvmDescriptor( final Class clazz )
{
return 'L' + clazz.getName().replace( '.', '/' ) + ';';
}
// ----------------------------------------------------------------------
// Implementation methods
// ----------------------------------------------------------------------
/**
* Adapts the given {@link ClassVisitor} to its equivalent ASM form.
*
* @param _cv The class visitor to adapt
* @return ASM-compatible class visitor
*/
private static org.eclipse.sisu.space.asm.ClassVisitor adapt( final ClassVisitor _cv )
{
return null == _cv ? null : new org.eclipse.sisu.space.asm.ClassVisitor( Opcodes.ASM9 )
{
@Override
public void visit( final int version, final int access, final String name, final String signature,
final String superName, final String[] interfaces )
{
_cv.enterClass( access, name, superName, interfaces );
}
@Override
public org.eclipse.sisu.space.asm.AnnotationVisitor visitAnnotation( final String desc,
final boolean visible )
{
final AnnotationVisitor _av = _cv.visitAnnotation( desc );
return null == _av ? null : new org.eclipse.sisu.space.asm.AnnotationVisitor( Opcodes.ASM9 )
{
{
_av.enterAnnotation();
}
@Override
public void visit( final String name, final Object value )
{
_av.visitElement( name, value instanceof Type ? ( (Type) value ).getClassName() : value );
}
@Override
public void visitEnd()
{
_av.leaveAnnotation();
}
};
}
@Override
public void visitEnd()
{
_cv.leaveClass();
}
};
}
}