cc.recommenders.nativelibs.NativeLibLoader.java Source code

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Here is the source code for cc.recommenders.nativelibs.NativeLibLoader.java

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/**
 * Copyright (c) 2011-2013 Darmstadt University of Technology.
 * 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:
 *     Sebastian Proksch - initial API and implementation
 * 
 * Idea adapted from:
 * http://stackoverflow.com/questions/12036607/ \
 *  bundle-native-dependencies-in-runnable-jar-with-maven
 */
package cc.recommenders.nativelibs;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.io.IOUtils;

public class NativeLibLoader {

    public static final String OS_ARCH = "os.arch";
    public static final String OS_NAME = "os.name";
    public static final String JAVA_IO_TMPDIR = "java.io.tmpdir";

    public void loadLibrary(String library) {
        try {
            String fileName = copyLibraryToTempFile(library);
            System.load(fileName);
        } catch (IOException e) {
            System.err.println("Could not find library " + library
                    + " as resource, trying fallback lookup through System.loadLibrary");
            System.loadLibrary(library);
        }
    }

    public String copyLibraryToTempFile(String library) throws IOException {
        InputStream in = null;
        OutputStream out = null;

        try {
            String libraryName = getContextAwareLibraryName(library);
            in = getClass().getClassLoader().getResourceAsStream("lib/" + libraryName);

            if (in == null) {
                fail("runtime not supported, '%s' missing in native bundle", libraryName);
            }

            File file = createTempFile(library);
            out = new FileOutputStream(file);

            int cnt;
            byte buf[] = new byte[16 * 1024];
            while ((cnt = in.read(buf)) >= 1) {
                out.write(buf, 0, cnt);
            }

            return file.getAbsolutePath();
        } finally {
            IOUtils.closeQuietly(in);
            IOUtils.closeQuietly(out);
        }
    }

    private String getContextAwareLibraryName(String library) {
        String osName = getOSName();
        String osArch = System.getProperty(OS_ARCH).toLowerCase();
        String extension = getExtension(osName);
        return String.format("%s-%s-%s.%s", library, osName, osArch, extension);
    }

    private String getOSName() {
        String property = System.getProperty(OS_NAME);
        String osNameOrig = property.toLowerCase().replaceAll(" ", "");
        if (osNameOrig.startsWith("win")) {
            return "win";
        } else {
            return osNameOrig;
        }
    }

    private String getExtension(String osName) {
        if (osName.startsWith("win")) {
            return "dll";
        } else if (osName.startsWith("linux")) {
            return "so";
        } else if (osName.startsWith("mac")) {
            return "jnilib";
        }
        fail("operating system '%s' not supported", osName);
        return null;
    }

    private void fail(String msg, Object... args) {
        throw new UnsupportedOperationException(String.format(msg, args));
    }

    private File createTempFile(String library) throws IOException {
        String tmpDirName = System.getProperty(JAVA_IO_TMPDIR);
        File tmpDir = new File(tmpDirName);
        if (!tmpDir.exists()) {
            tmpDir.mkdir();
        }
        File file = File.createTempFile(library + "-", ".tmp", tmpDir);
        // Clean up the file when exiting
        file.deleteOnExit();
        return file;
    }
}