| /* |
| * Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* @test |
| * @bug 4400571 |
| * @summary Verify that ObjectInputStream.available() functions properly when |
| * called at the beginning of a data block, and that it does not |
| * attempt any read operations that may potentially block. |
| */ |
| |
| import java.io.*; |
| |
| public class Available { |
| public static void main(String[] args) throws Exception { |
| ObjectOutputStream oout; |
| ByteArrayOutputStream bout; |
| byte[] buf; |
| |
| // write stream containing short data block |
| oout = new ObjectOutputStream(bout = new ByteArrayOutputStream()); |
| oout.write(new byte[100]); |
| oout.close(); |
| buf = bout.toByteArray(); |
| |
| // 4 byte stream header + 2 byte block header + data |
| if ((getAvailable(buf, 4) != 0) || (getAvailable(buf, 5) != 0)) { |
| throw new Error(); |
| } |
| for (int i = 0; i < 100; i++) { |
| if (getAvailable(buf, 6 + i) != i) { |
| throw new Error(); |
| } |
| } |
| |
| // write stream containing long data block |
| oout = new ObjectOutputStream(bout = new ByteArrayOutputStream()); |
| oout.write(new byte[500]); |
| oout.close(); |
| buf = bout.toByteArray(); |
| |
| // 4 byte stream header + 5 byte block header + data |
| for (int i = 4; i < 9; i++) { |
| if (getAvailable(buf, i) != 0) { |
| throw new Error(); |
| } |
| } |
| for (int i = 0; i < 500; i++) { |
| if (getAvailable(buf, 9 + i) != i) { |
| throw new Error(); |
| } |
| } |
| } |
| |
| /** |
| * Given a byte array containing a serialized stream, creates a copy of the |
| * given data truncated to the specified length, then returns the result of |
| * a call to available() on an ObjectInputStream created on top of the |
| * truncated data. As a side effect, a StreamCorrupted or EOFException |
| * will get thrown if the available() call attempts to read past the |
| * underlying stream's available data. |
| */ |
| static int getAvailable(byte[] data, int truncateLen) throws IOException { |
| byte[] trunc = new byte[truncateLen]; |
| System.arraycopy(data, 0, trunc, 0, truncateLen); |
| return new ObjectInputStream( |
| new ByteArrayInputStream(trunc)).available(); |
| } |
| } |