JarTools.java

package org.objectweb.jonas.web.lib;

//import java
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.FileOutputStream;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.Enumeration;

//import jonas
import org.objectweb.jonas.web.JWebContainerServiceException;

public class JarTools {

    private JarTools() {

    }

    private static final int BUFFER_SIZE = 2048;

    public static void unpack(String fileName, String destDir) throws JWebContainerServiceException {

        boolean doUnpack = false;

        // Check if the file to unpack exists.
        File jarFile = new File(fileName);
        if (!jarFile.exists()) {
            String err = "Cannot unpack " + fileName + " file does not exist";
            throw new JWebContainerServiceException(err);
        }

        // Check if the destination dir exists.
        File dest = new File(destDir);
        if (dest.exists()) {
            // Check if the destination directory is up to date and unpack it
            // if necessary.
            if (dest.lastModified() < jarFile.lastModified()) {
                if (removeDirectory(dest)) {
                    doUnpack = true;
                } else {
                    String err = "Cannot unpack " + fileName;
                    err = err + " cannot delete existing unpacked directory";
                    new JWebContainerServiceException(err);
                }
            } // else nothing to do the dest dir is up to date.
        } else {
            doUnpack = true;
        }

        // Unpack if necessary
        if (doUnpack) {
            JarFile packedJar = null;
            JarEntry entry = null;
            try {
                try {
                    packedJar = new JarFile(fileName);

                    //get entries of the jar file
                    Enumeration entries = packedJar.entries();
                    while (entries.hasMoreElements()) {
                        entry = (JarEntry) entries.nextElement();

                        //File entry
                        File entryFile = new File(destDir, entry.getName());

                        //Create directory
                        if (entry.isDirectory()) {
                            if (!entryFile.exists()) {
                                //create parent directories (with mkdirs)
                                if (!entryFile.mkdirs()) {
                                    String err = "Can not create directory " + entryFile + ", Check the write access.";
                                    throw new JWebContainerServiceException(err);
                                }
                            }
                            continue;
                        }

                        //If it's a file, we must extract the file
                        //Ensure that the directory exists.
                        entryFile.getParentFile().mkdirs();

                        InputStream is = null;
                        try {
                            //get the input stream
                            is = packedJar.getInputStream(entry);

                            //Dump to the file
                            dump(is, entryFile);
                        } finally {
                            is.close();
                        }
                    }
                } finally {
                    if (packedJar != null) {
                        packedJar.close();
                    }
                }
            } catch (IOException e) {
                String err = "Error while unpacking entry " + entry + " : ";
                err = err + e.getMessage();
                throw new JWebContainerServiceException(err);
            }
        }
    }

    private static void dump(InputStream in, File entryFile) throws JWebContainerServiceException {

        try {
            //File output
            FileOutputStream out = new FileOutputStream(entryFile);
            int n = 0;
            try {
                //buffer
                byte[] buffer = new byte[BUFFER_SIZE];
                n = in.read(buffer);
                while (n > 0) {
                    out.write(buffer, 0, n);
                    n = in.read(buffer);
                }
            } finally {
                out.close();
            }
        } catch (IOException e) {
            String err = "Error while unpacking entry " + entryFile + " : ";
            err = err + e.getMessage();
            throw new JWebContainerServiceException(err);
        }
    }

    private static boolean removeDirectory(File file) {
        boolean removeOk = true;

        //File or directory doesn't exists, exit.
        if (!file.exists()) {
            return false;
        }

        //Remove the child before the current file(directory)
        if (file.isDirectory()) {
            //remove all the children
            File[] childFiles = file.listFiles();
            for (int i = 0; i < childFiles.length; i++) {
                removeOk = removeOk && removeDirectory(childFiles[i]);
            }
        }
        //Since all childs are removed , remove us
        removeOk = removeOk && file.delete();
        return removeOk;
    }
}

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