try_with_resource.js revision 973:d564abed1e6a 
1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 *   - Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 *
11 *   - Redistributions in binary form must reproduce the above copyright
12 *     notice, this list of conditions and the following disclaimer in the
13 *     documentation and/or other materials provided with the distribution.
14 *
15 *   - Neither the name of Oracle nor the names of its
16 *     contributors may be used to endorse or promote products derived
17 *     from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/* This sample implements Java-like try..with..resource construct for nashorn */
33
34if (arguments.length == 0) {
35    print("Usage: jjs try_with_resource.js -- <file name>");
36    exit(1);
37}
38
39// Object.create accepts prototype and properties object
40function With(res) {
41   return Object.create(With.prototype,
42       { res: { value: res } });
43}
44
45// reserved words can be used as property names - for example "try"
46With.prototype.try = function(callback) {
47     try {
48         callback();
49     } finally {
50         this.res.close();
51     }
52}
53
54var BufferedReader = Java.type("java.io.BufferedReader");
55var FileReader = Java.type("java.io.FileReader");
56
57var r = new BufferedReader(new FileReader(arguments[0]));
58
59// Java-like try..with..resource
60With(r).try(function() {
61    var s;
62    while ((s = r.readLine()) != null) {
63        print(s);
64    }
65})
66