net.stickycode.bootstrap.guice4.AnnotationCollector.java Source code

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Here is the source code for net.stickycode.bootstrap.guice4.AnnotationCollector.java

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package net.stickycode.bootstrap.guice4;
/**
 * Copyright (C) 2010 Daniel Manzke <daniel.manzke@googlemail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

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;

import de.devsurf.injection.guice.scanner.features.ScannerFeature;

/**
 * Visitor implementation to collect field annotation information from class.
 *
 */
public class AnnotationCollector extends ClassVisitor {

    public static final int ASM_FLAGS = ClassReader.SKIP_CODE | ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES;

    protected Logger _logger = Logger.getLogger(AnnotationCollector.class.getName());

    protected String _name;

    protected Class<?> _class;

    protected boolean _ignore;

    protected Map<String, Annotation> _annotations;

    protected List<ScannerFeature> _features;

    public static final AnnotationVisitor EMPTY_ANNOTATION_VISITOR = new AnnotationVisitor(Opcodes.ASM4, null) {

        @Override
        public void visitEnum(String name, String desc, String value) {
        }

        @Override
        public void visitEnd() {
        }

        @Override
        public AnnotationVisitor visitArray(String name) {
            return this;
        }

        @Override
        public AnnotationVisitor visitAnnotation(String name, String desc) {
            return this;
        }

        @Override
        public void visit(String name, Object value) {
        }
    };

    public AnnotationCollector() {
        super(Opcodes.ASM4);
        _features = new LinkedList<ScannerFeature>();
        _annotations = new HashMap<String, Annotation>();
    }

    public void addScannerFeature(ScannerFeature listener) {
        _features.add(listener);
    }

    public void removerScannerFeature(ScannerFeature listener) {
        _features.remove(listener);
    }

    public List<ScannerFeature> getScannerFeatures() {
        return new ArrayList<ScannerFeature>(_features);
    }

    public void destroy() {
        _annotations.clear();
        _annotations = null;
        _class = null;
        _features.clear();
        _features = null;
    }

    @Override
    public void visit(int version, int access, String name, String signature, String superName,
            String[] interfaces) {
        _name = name.replace('/', '.');
        for (String interf : interfaces) {
            if (interf.equals("java/lang/annotation/Annotation")) {
                _ignore = true;
                return;
            }
        }
    }

    @SuppressWarnings("unchecked")
    public AnnotationVisitor visitAnnotation(String sig, boolean visible) {
        if (_ignore) {
            return EMPTY_ANNOTATION_VISITOR;
        }
        String annotationClassStr = sig.replace('/', '.').substring(1, sig.length() - 1);
        if (_class == null) {
            try {
                _class = getClass().getClassLoader().loadClass(_name);
            } catch (ClassNotFoundException e) {
                _logger.log(Level.WARNING, "Failure while visitAnnotation. Class could not be loaded.", e);
                return EMPTY_ANNOTATION_VISITOR;
            }
        }
        try {
            Class<Annotation> annotationClass = (Class<Annotation>) getClass().getClassLoader()
                    .loadClass(annotationClassStr);
            Annotation annotation = _class.getAnnotation(annotationClass);
            _annotations.put(annotationClassStr, annotation);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            _logger.log(Level.WARNING, "Failure while visitAnnotation. Class could not be loaded.", e);
        }

        return EMPTY_ANNOTATION_VISITOR;
    }

    @SuppressWarnings("unchecked")
    @Override
    public void visitEnd() {
        if (!_ignore && _annotations.size() > 0
                && !_annotations.containsKey("javax.enterprise.inject.Alternative")) {
            for (ScannerFeature listener : _features) {
                listener.found((Class<Object>) _class, _annotations);
            }
        }
        _name = null;
        _class = null;
        _ignore = false;
        _annotations.clear();
    }

    @Override
    public void visitAttribute(Attribute attr) {
    }

    @Override
    public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
        return null;
    }

    @Override
    public void visitInnerClass(String name, String outerName, String innerName, int access) {
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        return null;
    }

    @Override
    public void visitOuterClass(String owner, String name, String desc) {
    }

    @Override
    public void visitSource(String source, String debug) {
    }
}