tapestorage.java

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    public int getTotalRewindTime() {
        return rewindTime_;
    }

    /**
     * Gets the file with the specified name.
     * The time taken (in seconds) for getting the file can also be
     * found using {@link gridsim.datagrid.File#getTransactionTime()}.
     * @param fileName the name of the needed file
     * @return the file with the specified filename
     */
    public File getFile(String fileName) {
        File obj = null;

        // check first whether file name is valid or not
        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;

        // iterate linearly in a tape to find the file
        while (it.hasNext()) {
            obj = (File) it.next();
            size += obj.getSize();

            if (obj.getName().equals(fileName) == true) {
                found = true;
                break;
            }

            index++;
        }
        // if the file is found, then determine the time taken to get it
        if (found == true) {
            obj = (File) fileList_.get(index);
            double rewindTime = getRewindTime(size);
            double accessTime = getAccessTime(size - obj.getSize());
            double transferTime = getTransferTime(obj.getSize());

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

        return obj;
    }

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

    /**
     * Checks 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) {
        // check if the file is invalid or not
        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 accessTime = getAccessTime(currentSize_);
            double transferTime = getTransferTime(file.getSize());

            nameList_.add(file.getName());
            fileList_.add(file); // add the file into the tape
            currentSize_ += file.getSize(); // increment the current tape size

            // rewind time is calculated after the file has been written into
            // the tape. Hence, currentSize = currentSize + file size
            double rewindTime = getRewindTime(currentSize_);
            result = accessTime + transferTime + rewindTime; // total time
        }

        file.setTransactionTime(result);
        return result;
    }

    /**
     * Adds a set of files to the storage.
     * Run 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;

        // add each file in the list into the tape
        while (it.hasNext()) {
            file = (File) it.next();
            result += addFile(file);
        }

        return result;
    }

    /**
     * Removes a file from the storage -- <b>NOT SUPPORTED</b>.<br>
     * NOTE: a tape is supposed to be for backup purposes, once it is full,
     *       individual files can't be deleted unless the tape is cleared.
     * @param fileName the name of the file to be removed
     * @return <tt>null</tt>
     */
    public File deleteFile(String fileName) {
        System.out.println(name_ + ".deleteFile(): Not supported.");
        return null;
    }

    /**
     * Removes a file from the storage -- <b>NOT SUPPORTED</b>.<br>
     * NOTE: a tape is supposed to be for backup purposes, once it is full,
     *       individual files can't be deleted unless the tape is cleared.
     * @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 -- <b>NOT SUPPORTED</b>.<br>
     * NOTE: a tape is supposed to be for backup purposes, once it is full,
     *       individual files can't be deleted unless the tape is cleared.
     * @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) {
        System.out.println(name_ + ".deleteFile(): Not supported.");
        return 0.0;
    }

    // NOTE: I assume a tape has an indexing system, rather than search through
    // the whole tape.
    /**
     * 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;
    }

    /**
     * Gets the access time of this tape in seconds.
     * fileSize should be from the file starting point in the tape.
     *
     * @return  the access time in seconds.
     */
    private double getAccessTime(double fileSize) {
        double result = 0.0;
        if (fileSize > 0 && capacity_ != 0) {
            result = ((double) fileSize * accessTime_) / capacity_;
        }

        return result;
    }

    /**
     * Gets the rewind time in seconds.
     * fileSize should be from the file ending point in the tape.
     *
     * @return  the rewind time in seconds
     */
    private double getRewindTime(double fileSize) {
        double result = 0.0;
        if (fileSize > 0 && capacity_ != 0) {
            result = ((double) fileSize * rewindTime_) / capacity_;
        }

        return result;
    }

    /**
     * Gets the transfer time in seconds.
     * fileSize should be from the file ending point in the tape
     *
     * @return  the transfer time in seconds
     */
    private double getTransferTime(int fileSize) {
        double result = 0.0;
        if (fileSize > 0 && capacity_ != 0) {
            result = ((double) fileSize * maxTransferRate_) / capacity_;
        }

        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 conflict 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) {
                nameList_.remove(name);
                nameList_.add(newName);
                result = true;
                break;
            }
        }

        return result;
    }

} // end class