ANTLRFileStream.js revision 324c4644fee44b9898524c09511bd33c3f12e2df 
1/**
2 * Loads the contents of a file all at once and passes its contents off to
3 * {@link org.antlr.runtime.ANTLRStringStream}.
4 * Currently this class can only be used in the Rhino JS interpreter.
5 * @class
6 * @extends org.antlr.runtime.ANTLRStringStream
7 * @param {String} fileName path of the file to be loaded
8 * @param {String} [encoding] name of the charset used for decoding
9 */
10org.antlr.runtime.ANTLRFileStream = function(fileName, encoding) {
11    this.fileName = fileName;
12
13    // @todo need to add support for other JS interpreters that have file i/o
14    // hooks (SpiderMonkey and WSH come to mind).
15    var method;
16    if (org.antlr.env.ua.rhino) {
17        method = "loadFileUsingJava";
18    } else {
19        throw new Error(
20            "ANTLR File I/O is not supported in this JS implementation."
21        );
22    }
23
24    var data = this[method](fileName, encoding);
25    org.antlr.runtime.ANTLRFileStream.superclass.constructor.call(this, data);
26};
27
28org.antlr.lang.extend(org.antlr.runtime.ANTLRFileStream,
29                  org.antlr.runtime.ANTLRStringStream,
30/** @lends org.antlr.runtime.ANTLRFileStream.prototype */{
31    /**
32     * Get the file path from which the input was loaded.
33     * @returns {String} the file path from which the input was loaded
34     */
35    getSourceName: function() {
36        return this.fileName;
37    },
38
39    /**
40     * Read the file and return its contents as a JS string.
41     * @private
42     * @param {String} fileName path of the file to be loaded
43     * @param {String} [encoding] name of the charset used for decoding
44     * @returns {String} the contents of the file
45     */
46    loadFileUsingJava: function(fileName, encoding) {
47        // read the file using Java methods
48        var f = new java.io.File(fileName),
49            size = f.length(),
50            isr,
51            fis = new java.io.FileInputStream(f);
52        if (encoding) {
53            isr = new java.io.InputStreamReader(fis, encoding);
54        } else {
55            isr = new java.io.InputStreamReader(fis);
56        }
57        var data = java.lang.reflect.Array.newInstance(java.lang.Character.TYPE, size);
58        isr.read(data, 0, size);
59
60        // convert java char array to a javascript string
61        return new String(new java.lang.String(data));
62    }
63});
64