harddrivestorage.java

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        // check first whether file name is valid or not
        File obj = null;
        if (fileName == null || fileName.length() == 0) {
            System.out.println(name_ + ".getFile(): Warning - invalid "
                    + "file name.");
            return obj;
        }

        Iterator it = fileList_.iterator();
        int size = 0;
        int index = 0;
        boolean found = false;
        File tempFile = null;

        // find the file in the disk
        while (it.hasNext()) {
            tempFile = (File) it.next();
            size += tempFile.getSize();
            if (tempFile.getName().equals(fileName) == true) {
                found = true;
                obj = tempFile;
                break;
            }

            index++;
        }

        // if the file is found, then determine the time taken to get it
        if (found == true) {
            obj = (File) fileList_.get(index);
            double seekTime = getSeekTime(size);
            double transferTime = getTransferTime(obj.getSize());

            // total time for this operation
            obj.setTransactionTime(seekTime + transferTime);
        }

        return obj;
    }

    /**
     * Gets the list of file names located on this storage.
     * @return a LinkedList of file names
     */
    public List getFileNameList() {
        return nameList_;
    }

    /**
     * Get the seek time for a file with the defined size. Given a file size in
     * MB, this method returns a seek time for the file in seconds.
     *
     * @param fileSize the size of a file in MB
     * @return the seek time in seconds
     */
    private double getSeekTime(int fileSize) {
        double result = 0;

        if (gen_ != null) {
            result += gen_.sample();
        }

        if (fileSize > 0 && capacity_ != 0) {
            result += ((double) fileSize / capacity_);
        }

        return result;
    }

    /**
     * Gets the transfer time of a given file
     * @param fileSize  the size of the transferred file
     * @return the transfer time in seconds
     */
    private double getTransferTime(int fileSize) {
        double result = 0;
        if (fileSize > 0 && capacity_ != 0) {
            result = ((double) fileSize * maxTransferRate_) / capacity_;
        }

        return result;
    }

    /**
     * Check if the file is valid or not. This method checks whether the given
     * file or the file name of the file is valid. The method name parameter is
     * used for debugging purposes, to output in which method an error has
     * occured.
     *
     * @param file          the file to be checked for validity
     * @param methodName    the name of the method in which we check for
     *                      validity of the file
     * @return <tt>true</tt> if the file is valid, <tt>false</tt> otherwise
     */
    private boolean isFileValid(File file, String methodName) {

        if (file == null) {
            System.out.println(name_ + "." + methodName
                    + ": Warning - the given file is null.");
            return false;
        }

        String fileName = file.getName();
        if (fileName == null || fileName.length() == 0) {
            System.out.println(name_ + "." + methodName
                    + ": Warning - invalid file name.");
            return false;
        }

        return true;
    }

    /**
     * Adds a file to the storage. First, the method checks if there is enough
     * space on the storage, then it checks if the file with the same name is
     * already taken to avoid duplicate filenames. <br>
     * The time taken (in seconds) for adding the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     *
     * @param file  the file to be added
     * @return the time taken (in seconds) for adding the specified file
     */
    public double addFile(File file) {
        double result = 0.0;
        // check if the file is valid or not
        if (isFileValid(file, "addFile()") == false) {
            return result;
        }

        // check the capacity
        if (file.getSize() + currentSize_ > capacity_) {
            System.out.println(name_ + ".addFile(): Warning - not enough space"
                    + " to store " + file.getName());
            return result;
        }

        // check if the same file name is alredy taken
        if (contains(file.getName()) == false) {
            double seekTime = getSeekTime(file.getSize());
            double transferTime = getTransferTime(file.getSize());

            fileList_.add(file);               // add the file into the HD
            nameList_.add(file.getName());     // add the name to the name list
            currentSize_ += file.getSize();    // increment the current HD size
            result = seekTime + transferTime;  // add total time
        }
        file.setTransactionTime(result);
        return result;
    }

    /**
     * Adds a set of files to the storage.
     * Runs through the list of files and save all of them.
     * The time taken (in seconds) for adding each file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     *
     * @param list the files to be added
     * @return the time taken (in seconds) for adding the specified files
     */
    public double addFile(List list) {
        double result = 0.0;
        if (list == null || list.size() == 0) {
            System.out.println(name_ + ".addFile(): Warning - list is empty.");
            return result;
        }

        Iterator it = list.iterator();
        File file = null;
        while (it.hasNext()) {
            file = (File) it.next();
            result += addFile(file);    // add each file in the list
        }
        return result;
    }

    /**
     * Removes a file from the storage.
     * The time taken (in seconds) for deleting the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     *
     * @param fileName the name of the file to be removed
     * @return the deleted file
     */
    public File deleteFile(String fileName) {
        if (fileName == null || fileName.length() == 0) {
            return null;
        }

        Iterator it = fileList_.iterator();
        File file = null;
        while (it.hasNext()) {
            file = (File) it.next();
            String name = file.getName();

            // if a file is found then delete
            if (fileName.equals(name) == true) {
                double result = deleteFile(file);
                file.setTransactionTime(result);
                break;
            } else {
                file = null;
            }
        }
        return file;
    }

    /**
     * Removes a file from the storage.
     * The time taken (in seconds) for deleting the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     *
     * @param fileName  the name of the file to be removed
     * @param file      the file which is removed from the storage is returned
     *                  through this parameter
     * @return the time taken (in seconds) for deleting the specified file
     */
    public double deleteFile(String fileName, File file) {
        return deleteFile(file);
    }

    /**
     * Removes a file from the storage.
     * The time taken (in seconds) for deleting the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     *
     * @param file the file which is removed from the storage is returned
     *             through this parameter
     * @return the time taken (in seconds) for deleting the specified file
     */
    public double deleteFile(File file) {
        double result = 0.0;
        // check if the file is valid or not
        if (isFileValid(file, "deleteFile()") == false) {
            return result;
        }
        double seekTime = getSeekTime(file.getSize());
        double transferTime = getTransferTime(file.getSize());

        // check if the file is in the storage
        if (contains(file) == true) {
            fileList_.remove(file);            // remove the file HD
            nameList_.remove(file.getName());  //remove the name from name list
            currentSize_ -= file.getSize();    // decrement the current HD space
            result = seekTime + transferTime;  // total time
            file.setTransactionTime(result);
        }
        return result;
    }

    /**
     * Checks whether a certain file is on the storage or not.
     *
     * @param fileName  the name of the file we are looking for
     * @return <tt>true</tt> if the file is in the storage, <tt>false</tt>
     *         otherwise
     */
    public boolean contains(String fileName) {
        boolean result = false;
        if (fileName == null || fileName.length() == 0) {
            System.out.println(name_
                    + ".contains(): Warning - invalid file name");
            return result;
        }
        // check each file in the list
        Iterator it = nameList_.iterator();
        while (it.hasNext()) {
            String name = (String) it.next();
            if (name.equals(fileName) == true) {
                result = true;
                break;
            }
        }
        return result;
    }

    /**
     * Checks whether a certain file is on the storage or not.
     *
     * @param file the file we are looking for
     * @return <tt>true</tt> if the file is in the storage, <tt>false</tt>
     *         otherwise
     */
    public boolean contains(File file) {
        boolean result = false;
        if (isFileValid(file, "contains()") == false) {
            return result;
        }

        result = contains(file.getName());
        return result;
    }

    /**
     * Renames a file on the storage.
     * The time taken (in seconds) for renaming the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     * @param file      the file we would like to rename
     * @param newName   the new name of the file
     *
     * @return <tt>true</tt> if the renaming succeeded, <tt>false</tt>
     *         otherwise
     */
    public boolean renameFile(File file, String newName) {
        // check whether the new filename is conflicting with existing ones
        // or not
        boolean result = false;
        if (contains(newName) == true) {
            return result;
        }

        // replace the file name in the file (physical) list
        File obj = getFile(file.getName());
        if (obj != null) {
            obj.setName(newName);
        } else {
            return result;
        }

        // replace the file name in the name list
        Iterator it = nameList_.iterator();
        while (it.hasNext()) {
            String name = (String) it.next();
            if (name.equals(file.getName()) == true) {
                file.setTransactionTime(0);
                nameList_.remove(name);
                nameList_.add(newName);
                result = true;
                break;
            }
        }

        return result;
    }

} // end class