com.cognifide.cq.cqsm.core.actions.scanner.ClassScanner.java Source code

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Here is the source code for com.cognifide.cq.cqsm.core.actions.scanner.ClassScanner.java

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/*-
 * ========================LICENSE_START=================================
 * AEM Permission Management
 * %%
 * Copyright (C) 2013 Cognifide Limited
 * %%
 * 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.
 * =========================LICENSE_END==================================
 */
package com.cognifide.cq.cqsm.core.actions.scanner;

import org.apache.commons.lang.StringUtils;
import org.apache.sling.commons.osgi.PropertiesUtil;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.annotation.Annotation;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

/**
 * Utility class for searching classes in specified bundle
 * If bundle context is provided it can also support fragment bundles
 */
public class ClassScanner {

    private final Bundle bundle;

    private final BundleContext context;

    public ClassScanner(Bundle bundle) {
        this(bundle, null);
    }

    public ClassScanner(Bundle bundle, BundleContext context) {
        this.bundle = bundle;
        this.context = context;
    }

    private static final Logger LOG = LoggerFactory.getLogger(ClassScanner.class);

    public List<Class<?>> findClasses(String packageName) {
        @SuppressWarnings("unchecked")
        final Enumeration<URL> classUrls = bundle.findEntries(packageName.replace('.', '/'), "*.class", true);
        final String bundleName = bundle.getSymbolicName();
        final ArrayList<Class<?>> classes = new ArrayList<>();

        if (classUrls == null) {
            LOG.warn("No classes found in bundle: {}", bundleName);
        } else {
            while (classUrls.hasMoreElements()) {
                final URL url = classUrls.nextElement();
                final String className = toClassName(url);

                try {
                    if (BundleUtils.isFragment(bundle)) {
                        if (context == null) {
                            LOG.warn("Cannot load class from fragment bundle {} if context is unspecified",
                                    bundleName);
                        }

                        final Bundle hostBundle = BundleUtils.getHostBundle(context, bundle);

                        if (hostBundle == null) {
                            LOG.warn("Cannot find host bundle for {}", bundleName);
                        } else {
                            classes.add(hostBundle.loadClass(className));
                        }
                    } else {
                        classes.add(bundle.loadClass(className));
                    }
                } catch (ClassNotFoundException e) {
                    LOG.warn("Unable to load class", e);
                }
            }
        }

        return classes;
    }

    public List<Class<?>> findClasses(List<String> packages, Class<? extends Annotation> annotation) {
        ArrayList<Class<?>> classes = new ArrayList<>();

        for (String packageName : packages) {
            for (Class<?> clazz : findClasses(packageName)) {
                if (clazz != null && (annotation == null || clazz.isAnnotationPresent(annotation))) {
                    classes.add(clazz);
                }
            }
        }

        return classes;
    }

    public List<Class<?>> findClasses(String header, Class<? extends Annotation> annotation) {
        return findClasses(parsePackagesFromHeader(header), annotation);
    }

    public List<Class<?>> findClasses(Class<? extends Annotation> annotation) {
        return findClasses(Collections.singletonList("/"), annotation);
    }

    public List<Class<?>> findClasses() {
        return findClasses(Collections.singletonList("/"), null);
    }

    private String toClassName(URL url) {
        final String f = url.getFile();
        final String cn = f.substring(1, f.length() - ".class".length());
        return cn.replace('/', '.');
    }

    private List<String> parsePackagesFromHeader(String header) {
        String values = PropertiesUtil.toString(bundle.getHeaders().get(header), null);
        if (values == null) {
            return Collections.emptyList();
        }
        String[] packages = StringUtils.deleteWhitespace(values).split(";");

        return Arrays.asList(packages);
    }
}