Add a minimal FilterInputStream

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

classpath/java/io/FilterInputStream.java

@@ -0,0 +1,35 @@
+/* Copyright (c) 2008-2013, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.io;
+
+public class FilterInputStream extends InputStream {
+  protected InputStream in;
+
+  public FilterInputStream(InputStream in) {
+    this.in = in;
+  }
+
+  public void close() throws IOException {
+    in.close();
+  }
+
+  public int read(byte[] b) throws IOException {
+    return in.read(b);
+  }
+
+  public int read(byte[] b, int off, int len) throws IOException {
+    return in.read(b, off, len);
+  }
+
+  public int read() throws IOException {
+    return in.read();
+  }
+}