001 /* 002 * Copyright (C) 2010 eXo Platform SAS. 003 * 004 * This is free software; you can redistribute it and/or modify it 005 * under the terms of the GNU Lesser General Public License as 006 * published by the Free Software Foundation; either version 2.1 of 007 * the License, or (at your option) any later version. 008 * 009 * This software is distributed in the hope that it will be useful, 010 * but WITHOUT ANY WARRANTY; without even the implied warranty of 011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 012 * Lesser General Public License for more details. 013 * 014 * You should have received a copy of the GNU Lesser General Public 015 * License along with this software; if not, write to the Free 016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org. 018 */ 019 020 package org.crsh.util; 021 022 import java.io.IOException; 023 import java.io.InputStream; 024 025 /** 026 * A stream that reads a portion of a delegate input stream. 027 * The impl is very basic and could be improved but it is enough at the moment. 028 * 029 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a> 030 * @version $Revision$ 031 */ 032 public class SubInputStream extends InputStream { 033 034 /** . */ 035 private final InputStream in; 036 037 /** . */ 038 private final long length; 039 040 /** . */ 041 private long count; 042 043 public SubInputStream(InputStream in, long length) { 044 if (in == null) { 045 throw new NullPointerException("Stream cannot be null"); 046 } 047 if (length < 0) { 048 throw new IllegalArgumentException("Length cannot be negative"); 049 } 050 051 // 052 this.in = in ; 053 this.length = length; 054 this.count = 0; 055 } 056 057 @Override 058 public int read() throws IOException { 059 if (count < length) { 060 int value = in.read(); 061 count++; 062 return value; 063 } else { 064 return -1; 065 } 066 } 067 }