nashorn/samples/try_with_resource.js
author bchristi
Fri, 08 Jan 2016 13:14:30 -0800
changeset 34934 7fbff68dbc12
parent 26070 1c348e8d9b88
permissions -rw-r--r--
8144552: java/lang/StackWalker/LocalsAndOperands.java fails with java.lang.NullPointerException Summary: Update test case to expect null Reviewed-by: mchung, dfuchs

/*
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 * are met:
 *
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 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 */

/* This sample implements Java-like try..with..resource construct for nashorn */

if (arguments.length == 0) {
    print("Usage: jjs try_with_resource.js -- <file name>");
    exit(1);
}

// Object.create accepts prototype and properties object
function With(res) {
   return Object.create(With.prototype,
       { res: { value: res } });
}

// reserved words can be used as property names - for example "try"
With.prototype.try = function(callback) {
     try {
         callback();
     } finally {
         this.res.close();
     }
}

var BufferedReader = Java.type("java.io.BufferedReader");
var FileReader = Java.type("java.io.FileReader");

var r = new BufferedReader(new FileReader(arguments[0]));

// Java-like try..with..resource
With(r).try(function() {
    var s;
    while ((s = r.readLine()) != null) {
        print(s);
    }
})