org.apache.commons.io.comparator.NameFileComparator#NAME_SYSTEM_COMPARATOR源码实例Demo

/**
 * Construct an observer for the specified directory, file filter and
 * file comparator.
 *
 * @param rootEntry the root directory to observe
 * @param fileFilter The file filter or null if none
 * @param caseSensitivity  what case sensitivity to use comparing file names, null means system sensitive
 */
protected FileAlterationObserver(FileEntry rootEntry, FileFilter fileFilter, IOCase caseSensitivity) {
    if (rootEntry == null) {
        throw new IllegalArgumentException("Root entry is missing");
    }
    if (rootEntry.getFile() == null) {
        throw new IllegalArgumentException("Root directory is missing");
    }
    this.rootEntry = rootEntry;
    this.fileFilter = fileFilter;
    if (caseSensitivity == null || caseSensitivity.equals(IOCase.SYSTEM)) {
        this.comparator = NameFileComparator.NAME_SYSTEM_COMPARATOR;
    } else if (caseSensitivity.equals(IOCase.INSENSITIVE)) {
        this.comparator = NameFileComparator.NAME_INSENSITIVE_COMPARATOR;
    } else {
        this.comparator = NameFileComparator.NAME_COMPARATOR;
    }
}
 

/**
 * Construct an observer for the specified directory, file filter and
 * file comparator.
 *
 * @param rootEntry the root directory to observe
 * @param fileFilter The file filter or null if none
 * @param caseSensitivity  what case sensitivity to use comparing file names, null means system sensitive
 */
protected FileAlterationObserver(final FileEntry rootEntry, final FileFilter fileFilter,
                                 final IOCase caseSensitivity) {
    if (rootEntry == null) {
        throw new IllegalArgumentException("Root entry is missing");
    }
    if (rootEntry.getFile() == null) {
        throw new IllegalArgumentException("Root directory is missing");
    }
    this.rootEntry = rootEntry;
    this.fileFilter = fileFilter;
    if (caseSensitivity == null || caseSensitivity.equals(IOCase.SYSTEM)) {
        this.comparator = NameFileComparator.NAME_SYSTEM_COMPARATOR;
    } else if (caseSensitivity.equals(IOCase.INSENSITIVE)) {
        this.comparator = NameFileComparator.NAME_INSENSITIVE_COMPARATOR;
    } else {
        this.comparator = NameFileComparator.NAME_COMPARATOR;
    }
}
 

protected Comparator<File> convertSortOrder()
{
    Comparator<File> result = NameFileComparator.NAME_COMPARATOR;
    if ( getSortOrder().equalsIgnoreCase( "NAME_INSENSITIVE_COMPARATOR" ) )
    {
        result = NameFileComparator.NAME_INSENSITIVE_COMPARATOR;
    }
    else if ( getSortOrder().equalsIgnoreCase( "NAME_INSENSITIVE_REVERSE" ) )
    {
        result = NameFileComparator.NAME_INSENSITIVE_REVERSE;
    }
    else if ( getSortOrder().equalsIgnoreCase( "NAME_REVERSE" ) )
    {
        result = NameFileComparator.NAME_REVERSE;
    }
    else if ( getSortOrder().equalsIgnoreCase( "NAME_SYSTEM_COMPARATOR" ) )
    {
        result = NameFileComparator.NAME_SYSTEM_COMPARATOR;
    }
    else if ( getSortOrder().equalsIgnoreCase( "NAME_SYSTEM_REVERSE" ) )
    {
        result = NameFileComparator.NAME_SYSTEM_REVERSE;
    }
    return result;
}