001    /*
002     * Copyright (C) 2012 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    public class SubInputStream extends InputStream {
026    
027      /** . */
028      private final InputStream in;
029    
030      /** . */
031      private final long length;
032    
033      /** . */
034      private long count;
035    
036      public SubInputStream(InputStream in, long length) {
037        if (in == null) {
038          throw new NullPointerException("Stream cannot be null");
039        }
040        if (length < 0) {
041          throw new IllegalArgumentException("Length cannot be negative");
042        }
043    
044        //
045        this.in = in ;
046        this.length = length;
047        this.count = 0;
048      }
049    
050      @Override
051      public int read() throws IOException {
052        if (count < length) {
053          int value = in.read();
054          count++;
055          return value;
056        } else {
057          return -1;
058        }
059      }
060    }