samples/uniq.js

/*
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 * 
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 * modification, are permitted provided that the following conditions
 * are met:
 * 
 *   - Redistributions of source code must retain the above copyright
 *     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,
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 */

/**
 * Prints unique lines from a given file.
 */

if (arguments.length != 1) {
    print("Usage: jjs uniq.js -- <file>");
    java.lang.System.exit(1);
}

var imports = new JavaImporter(java.io);

var uniqueLines = {};
with (imports) {
    var reader = new BufferedReader(new FileReader(arguments[0]));
    while ((line = reader.readLine()) != null) {
        // using a JS object as a map...
        uniqueLines[line] = true;
    }
}

// now print the collected lines
for (i in uniqueLines) {
    print(i);
}