org.analogweb.util.ResourceUtils Maven / Gradle / Ivy

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package org.analogweb.util;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.analogweb.util.logging.Log;
import org.analogweb.util.logging.Logs;

/**
 * @author snowgoose
 */
public final class ResourceUtils {

    private static final Log log = Logs.getLog(ResourceUtils.class);
    private static final List DEFAULT_STRATEGIES = Arrays.asList(new ResourceFinder[] {
            FindResourceStrategies.CLASSPATH, FindResourceStrategies.URL, FindResourceStrategies.FILE });

    public static URL findResource(String name) {
        if (StringUtils.isEmpty(name)) {
            return null;
        }
        return findResource(name, DEFAULT_STRATEGIES);
    }

    public static URL findResource(String name, List strategies) {
        URL found;
        for (ResourceFinder strategy : strategies) {
            found = strategy.find(name);
            if (found != null) {
                return found;
            }
        }
        return null;
    }

    public static List findPackageResources(String packageName, ClassLoader classLoader) {
        return findResources(packageName.replace('.', '/'), classLoader);
    }

    public static List findResources(String name, ClassLoader classLoader) {
        List found = new ArrayList();
        try {
            Enumeration urls = classLoader.getResources(name);
            while (urls.hasMoreElements()) {
                if (urls != null) {
                    found.add(urls.nextElement());
                }
            }
        } catch (IOException e) {
            return Collections.emptyList();
        }
        return found;
    }

    public interface ResourceFinder {

        URL find(String name);
    }

    public interface FindResourceStrategies {

        static final ResourceFinder FILE = new ResourceFinder() {

            @Override
            public URL find(String filename) {
                try {
                    char sep = File.separator.charAt(0);
                    String file = filename.replace(sep, '/');
                    if (file.charAt(0) != '/') {
                        String dir = SystemProperties.userDir();
                        dir = dir.replace(sep, '/') + '/';
                        if (dir.charAt(0) != '/') {
                            dir = "/" + dir;
                        }
                    }
                    URL fileURL = new URL("file", null, file);
                    if (new File(file).exists() == false) {
                        log.log("DU000002", fileURL);
                        return null;
                    }
                    log.log("DU000001", fileURL);
                    return fileURL;
                } catch (MalformedURLException e) {
                    log.log("DU000002", e);
                    return null;
                }
            }
        };
        static final ResourceFinder CLASSPATH = new ResourceFinder() {

            @Override
            public URL find(String name) {
                URL resource = Thread.currentThread().getContextClassLoader().getResource(name);
                if (resource != null) {
                    log.log("DU000003", resource.getPath());
                    return resource;
                } else {
                    log.log("DU000004", name);
                    return null;
                }
            }
        };
        static final ResourceFinder URL = new ResourceFinder() {

            @Override
            public URL find(String name) {
                try {
                    URL url = new URL(name);
                    log.log("DU000005", name);
                    return url;
                } catch (MalformedURLException e) {
                    log.log("DU000006", name);
                    return null;
                }
            }
        };
    }
}