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package org.glassfish.jersey.server.internal.scanning;
import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.ws.rs.Path;
import javax.ws.rs.ext.Provider;
import org.glassfish.jersey.internal.OsgiRegistry;
import org.glassfish.jersey.internal.util.ReflectionHelper;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
/**
* A scanner listener that processes Java class files (resource names
* ending in ".class") annotated with one or more of a set of declared
* annotations.
* <p>
* Java classes of a Java class file are processed, using ASM, to ascertain
* if those classes are annotated with one or more of the set of declared
* annotations.
* <p>
* Such an annotated Java class of a Java class file is loaded if the class
* is public or is an inner class that is static and public.
*
* @author Paul Sandoz
*/
public final class AnnotationAcceptingListener implements ResourceProcessor {
private final ClassLoader classloader;
private final Set<Class<?>> classes;
private final Set<String> annotations;
private final AnnotatedClassVisitor classVisitor;
/**
* Create a scanning listener to check for Java classes in Java
* class files annotated with {@link javax.ws.rs.Path} or {@link javax.ws.rs.ext.Provider}.
*
* @return new instance of {@link AnnotationAcceptingListener} which looks for
* {@link javax.ws.rs.Path} or {@link javax.ws.rs.ext.Provider} annotated classes.
*
*/
@SuppressWarnings({"unchecked"})
public static AnnotationAcceptingListener newJaxrsResourceAndProviderListener() {
return new AnnotationAcceptingListener(Path.class, Provider.class);
}
/**
* Create a scanning listener to check for Java classes in Java
* class files annotated with {@link Path} or {@link Provider}.
*
* @param classLoader the class loader to use to load Java classes that
* are annotated with any one of the annotations.
* @return new instance of {@link AnnotationAcceptingListener} which looks for
* {@link javax.ws.rs.Path} or {@link javax.ws.rs.ext.Provider} annotated classes.
*/
@SuppressWarnings({"unchecked"})
public static AnnotationAcceptingListener newJaxrsResourceAndProviderListener(ClassLoader classLoader) {
return new AnnotationAcceptingListener(classLoader, Path.class, Provider.class);
}
/**
* Create a scanner listener to check for annotated Java classes in Java
* class files.
*
* @param annotations the set of annotation classes to check on Java class
* files.
*/
public AnnotationAcceptingListener(Class<? extends Annotation>... annotations) {
this(ReflectionHelper.getContextClassLoader(), annotations);
}
/**
* Create a scanner listener to check for annotated Java classes in Java
* class files.
*
* @param classloader the class loader to use to load Java classes that
* are annotated with any one of the annotations.
* @param annotations the set of annotation classes to check on Java class
* files.
*/
public AnnotationAcceptingListener(ClassLoader classloader,
Class<? extends Annotation>... annotations) {
this.classloader = classloader;
this.classes = new LinkedHashSet<Class<?>>();
this.annotations = getAnnotationSet(annotations);
this.classVisitor = new AnnotatedClassVisitor();
}
/**
* Get the set of annotated classes.
*
* @return the set of annotated classes.
*/
public Set<Class<?>> getAnnotatedClasses() {
return classes;
}
private Set<String> getAnnotationSet(Class<? extends Annotation>... annotations) {
Set<String> a = new HashSet<String>();
for (Class c : annotations) {
a.add("L" + c.getName().replaceAll("\\.", "/") + ";");
}
return a;
}
// ScannerListener
public boolean accept(String name) {
return !(name == null || name.isEmpty()) && name.endsWith(".class");
}
public void process(String name, InputStream in) throws IOException {
new ClassReader(in).accept(classVisitor, 0);
}
//
private final class AnnotatedClassVisitor implements ClassVisitor {
/**
* The name of the visited class.
*/
private String className;
/**
* True if the class has the correct scope
*/
private boolean isScoped;
/**
* True if the class has the correct declared annotations
*/
private boolean isAnnotated;
public void visit(int version, int access, String name,
String signature, String superName, String[] interfaces) {
className = name;
isScoped = (access & Opcodes.ACC_PUBLIC) != 0;
isAnnotated = false;
}
public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
isAnnotated |= annotations.contains(desc);
return null;
}
public void visitInnerClass(String name, String outerName,
String innerName, int access) {
// If the name of the class that was visited is equal
// to the name of this visited inner class then
// this access field needs to be used for checking the scope
// of the inner class
if (className.equals(name)) {
isScoped = (access & Opcodes.ACC_PUBLIC) != 0;
// Inner classes need to be statically scoped
isScoped &= (access & Opcodes.ACC_STATIC) == Opcodes.ACC_STATIC;
}
}
public void visitEnd() {
if (isScoped && isAnnotated) {
// Correctly scoped and annotated
// add to the set of matching classes.
classes.add(getClassForName(className.replaceAll("/", ".")));
}
}
public void visitOuterClass(String string, String string0,
String string1) {
// Do nothing
}
public FieldVisitor visitField(int i, String string,
String string0, String string1,
Object object) {
// Do nothing
return null;
}
public void visitSource(String string, String string0) {
// Do nothing
}
public void visitAttribute(Attribute attribute) {
// Do nothing
}
public MethodVisitor visitMethod(int i, String string,
String string0, String string1,
String[] string2) {
// Do nothing
return null;
}
private Class getClassForName(String className) {
try {
final OsgiRegistry osgiRegistry = ReflectionHelper.getOsgiRegistryInstance();
if (osgiRegistry != null) {
return osgiRegistry.classForNameWithException(className);
} else {
return ReflectionHelper.classForNameWithException(className, classloader);
}
} catch (ClassNotFoundException ex) {
String s = "A class file of the class name, " +
className +
"is identified but the class could not be found";
throw new RuntimeException(s, ex);
}
}
}
}