Jetty example source code file (InclusiveByteRange.java)

This example Jetty source code file (InclusiveByteRange.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Jetty tags/keywords

bad, bad, inclusivebyterange, inclusivebyterange, list, object, string, string, stringbuffer, stringbuffer, stringtokenizer, util

The Jetty InclusiveByteRange.java source code

// ========================================================================
// Copyright 2002-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at 
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ========================================================================

package org.mortbay.jetty;

import java.util.Enumeration;
import java.util.List;
import java.util.StringTokenizer;

import org.mortbay.log.Log;
import org.mortbay.util.LazyList;

/* ------------------------------------------------------------ */
/** Byte range inclusive of end points.
 * <PRE>
 * 
 *   parses the following types of byte ranges:
 * 
 *       bytes=100-499
 *       bytes=-300
 *       bytes=100-
 *       bytes=1-2,2-3,6-,-2
 *
 *   given an entity length, converts range to string
 * 
 *       bytes 100-499/500
 * 
 * </PRE>
 * 
 * Based on RFC2616 3.12, 14.16, 14.35.1, 14.35.2
 * @version $version$
 * @author Helmut Hissen
 */
public class InclusiveByteRange 
{
    long first = 0;
    long last  = 0;    

    public InclusiveByteRange(long first, long last)
    {
        this.first = first;
        this.last = last;
    }
    
    public long getFirst()
    {
        return first;
    }

    public long getLast()
    {
        return last;
    }    


    
    /* ------------------------------------------------------------ */
    /** 
     * @param headers Enumeration of Range header fields.
     * @param size Size of the resource.
     * @return LazyList of satisfiable ranges
     */
    public static List satisfiableRanges(Enumeration headers,long size)
    {
        Object satRanges=null;
        
        // walk through all Range headers
    headers:
        while (headers.hasMoreElements())
        {
            String header = (String) headers.nextElement();
            StringTokenizer tok = new StringTokenizer(header,"=,",false);
            String t=null;
            try
            {
                // read all byte ranges for this header 
                while (tok.hasMoreTokens())
                {
                    t=tok.nextToken().trim();
                    
                    long first = -1;
                    long last  = -1;
                    int d=t.indexOf('-');
                    if (d<0 || t.indexOf("-",d+1)>=0)
                    {           
                        if ("bytes".equals(t))
                            continue;
                        Log.warn("Bad range format: {}",t);
                        continue headers;
                    }
                    else if (d==0)
                    {
                        if (d+1<t.length())
                            last = Long.parseLong(t.substring(d+1).trim());
                        else
                        {
                            Log.warn("Bad range format: {}",t);
                            continue headers;
                        }
                    }
                    else if (d+1<t.length())
                    {
                        first = Long.parseLong(t.substring(0,d).trim());
                        last = Long.parseLong(t.substring(d+1).trim());
                    }
                    else
                        first = Long.parseLong(t.substring(0,d).trim());

                    
                    if (first == -1 && last == -1)
                        continue headers;
                    
                    if (first != -1 && last != -1 && (first > last))
                        continue headers;

                    if (first<size)
                    {
                        InclusiveByteRange range = new
                            InclusiveByteRange(first, last);
                        satRanges=LazyList.add(satRanges,range);
                    }
                }
            }
            catch(Exception e)
            {
                Log.warn("Bad range format: "+t);
                Log.ignore(e);
            }    
        }
        return LazyList.getList(satRanges,true);
    }

    /* ------------------------------------------------------------ */
    public long getFirst(long size)
    {
        if (first<0)
        {
            long tf=size-last;
            if (tf<0)
                tf=0;
            return tf;
        }
        return first;
    }
    
    /* ------------------------------------------------------------ */
    public long getLast(long size)
    {
        if (first<0)
            return size-1;
        
        if (last<0 ||last>=size)
            return size-1;
        return last;
    }
    
    /* ------------------------------------------------------------ */
    public long getSize(long size)
    {
        return getLast(size)-getFirst(size)+1;
    }


    /* ------------------------------------------------------------ */
    public String toHeaderRangeString(long size)
    {
        StringBuffer sb = new StringBuffer(40);
        sb.append("bytes ");
        sb.append(getFirst(size));
        sb.append('-');
        sb.append(getLast(size));
        sb.append("/");
        sb.append(size);
        return sb.toString();
    }

    /* ------------------------------------------------------------ */
    public static String to416HeaderRangeString(long size)
    {
        StringBuffer sb = new StringBuffer(40);
        sb.append("bytes */");
        sb.append(size);
        return sb.toString();
    }


    /* ------------------------------------------------------------ */
    public String toString()
    {
        StringBuffer sb = new StringBuffer(60);
        sb.append(Long.toString(first));
        sb.append(":");
        sb.append(Long.toString(last));
        return sb.toString();
    }


}