package com.trendmicro.grid.acl.ds.jpa.util;
   
   import java.io.FilterWriter;
   import java.io.IOException;
   import java.io.Writer;
   
   /**
    * Is a filter stream that limits the maximum amount of characters written to the underlying stream.
    *
   * @author juergen_kellerer, 2010-07-14
   * @version 1.0
   */
  public class LimitedWriter extends FilterWriter {
  
  	public static class OutOfBounds extends IOException {
  		private static final long serialVersionUID = 5731925583780832667L;
  	}
  
  	long writtenChars, limit;
  
  	public LimitedWriter(Writer out, long limit) {
  		super(out);
  		this.limit = limit;
  	}
  
  	void assertCanWrite(int byteCount) throws IOException {
  		if (limit - writtenChars < byteCount)
  			throw new OutOfBounds();
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public void write(int c) throws IOException {
  		assertCanWrite(1);
  		super.write(c);
  		writtenChars++;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public void write(char[] cbuf, int off, int len) throws IOException {
  		assertCanWrite(len);
  		super.write(cbuf, off, len);
  		writtenChars += len;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public void write(String str, int off, int len) throws IOException {
  		assertCanWrite(len);
  		super.write(str, off, len);
  		writtenChars += len;
  	}
  }