exceptionutilities.java

FuncPlotter is a combined Java application and applet for displaying two-dimensional plots of explic

/*====================================================================*\

ExceptionUtilities.java

Exception utilities class.

------------------------------------------------------------------------

This file is part of FuncPlotter, a combined Java application and applet
for plotting explicit functions in one variable.
Copyright 2005-2007 Andy Morgan-Richards.

FuncPlotter is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see <http://www.gnu.org/licenses/>.

\*====================================================================*/


// PACKAGE


package exception;

//----------------------------------------------------------------------


// IMPORTS


import java.io.File;
import java.io.IOException;

import java.util.ArrayList;
import java.util.List;

//----------------------------------------------------------------------


// EXCEPTION UTILITIES CLASS


public class ExceptionUtilities
{

////////////////////////////////////////////////////////////////////////
//  Constants
////////////////////////////////////////////////////////////////////////

    private static final    String  ELLIPSIS_STR    = "...";

////////////////////////////////////////////////////////////////////////
//  Constructors
////////////////////////////////////////////////////////////////////////

    private ExceptionUtilities( )
    {
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Class methods
////////////////////////////////////////////////////////////////////////

    public static boolean isUnix( )
    {
        return unix;
    }

    //------------------------------------------------------------------

    public static void setUnix( boolean unix )
    {
        ExceptionUtilities.unix = unix;
    }

    //------------------------------------------------------------------

    public static String getLimitedPathname( File file,
                                             int  maxLength )
    {
        String pathname = null;
        try
        {
            pathname = file.getCanonicalPath( );
        }
        catch ( IOException e )
        {
            System.err.println( e );
            StackTraceElement[] stackTraceElements = e.getStackTrace( );
            if ( stackTraceElements.length > 0 )
                System.err.println( stackTraceElements[0] );
            pathname = file.getAbsolutePath( );
        }

        if ( unix )
        {
            try
            {
                String userHome = System.getProperty( "user.home" );
                if ( (userHome != null) && pathname.startsWith( userHome ) )
                    pathname = "~" + pathname.substring( userHome.length( ) );
            }
            catch ( SecurityException e )
            {
                // ignore
            }
            if ( File.separatorChar != '/' )
                pathname = pathname.replace( File.separatorChar, '/' );
        }

        return getLimitedPathname( pathname, maxLength );
    }

    //------------------------------------------------------------------

    public static String getLimitedPathname( String pathname,
                                             int    maxLength )
    {

        // Test for null pathname

        if ( pathname == null )
            return null;

        // Split the pathname into its components

        char separatorChar = unix ? '/' : File.separatorChar;
        List<String> strs = new ArrayList<String>( );
        int index = 0;
        while ( index < pathname.length( ) )
        {
            int startIndex = index;
            index = pathname.indexOf( separatorChar, index );
            if ( index < 0 )
                index = pathname.length( );
            if ( index > startIndex )
                strs.add( pathname.substring( startIndex, index ) );
            ++index;
        }
        if ( strs.isEmpty( ) )
            return pathname;

        // Get the maximum number of components

        StringBuilder buffer = new StringBuilder( ELLIPSIS_STR );
        int numComponents = 0;
        for ( int i = strs.size( ) - 1; i >= 0; --i )
        {
            buffer.append( separatorChar );
            buffer.append( strs.get( i ) );
            if ( buffer.length( ) > maxLength )
                break;
            ++numComponents;
        }

        // If last component is too wide, remove leading characters until it fits

        if ( numComponents == 0 )
        {
            String str = strs.get( strs.size( ) - 1 );
            return ( ELLIPSIS_STR + str.substring( Math.max( 0, str.length( ) - maxLength +
                                                                            ELLIPSIS_STR.length( ) ) ) );
        }

        // If the entire pathname fits, return it

        if ( numComponents == strs.size( ) )
            return pathname;

        // Construct a reduced pathname

        buffer = new StringBuilder( ELLIPSIS_STR );
        for ( int i = strs.size( ) - numComponents; i < strs.size( ); ++i )
        {
            buffer.append( separatorChar );
            buffer.append( strs.get( i ) );
        }
        return buffer.toString( );

    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Class variables
////////////////////////////////////////////////////////////////////////

    private static  boolean unix;

}

//----------------------------------------------------------------------