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#// Usage: jjs -scripting javashell.js
/*
* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* 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,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// Simple Java "shell" with which you can try out
// your few liner Java code leaving imports, main etc.
// And you can leave even compilation as this script
// takes care boilerplate+compile step for you.
// Java types used
var Arrays = Java.type("java.util.Arrays");
var BufferedReader = Java.type("java.io.BufferedReader");
var FileWriter = Java.type("java.io.FileWriter");
var LocalDateTime = Java.type("java.time.LocalDateTime");
var InputStreamReader = Java.type("java.io.InputStreamReader");
var PrintWriter = Java.type("java.io.PrintWriter");
var ProcessBuilder = Java.type("java.lang.ProcessBuilder");
var System = Java.type("java.lang.System");
// read multiple lines of input from stdin till user
// enters an empty line
function input(endMarker, prompt) {
if (!endMarker) {
endMarker = "";
}
if (!prompt) {
prompt = " >> ";
}
var str = "";
var reader = new BufferedReader(new InputStreamReader(System.in));
var line;
while (true) {
System.out.print(prompt);
line = reader.readLine();
if (line == null || line == endMarker) {
break;
}
str += line + "\n";
}
return str;
}
// write the string to the given file
function writeTo(file, str) {
var w = new PrintWriter(new FileWriter(file));
try {
w.print(str);
} finally {
w.close();
}
}
// generate Java code with user's input
// put inside generated main method
function generate(className) {
var usercode = input();
if (usercode == "") {
return false;
}
var fullcode = <<EOF
// userful imports, add more here if you want
// more imports.
import static java.lang.System.*;
import java.io.*;
import java.net.*;
import java.math.*;
import java.nio.file.*;
import java.time.*;
import java.time.chrono.*;
import java.time.format.*;
import java.time.temporal.*;
import java.time.zone.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.stream.*;
public class ${className} {
public static void main(String[] args) throws Exception {
${usercode}
}
}
EOF
writeTo("${className}.java", fullcode);
return true;
}
// execute code command
function exec(args) {
// build child process and start it!
new ProcessBuilder(Arrays.asList(args.split(' ')))
.inheritIO()
.start()
.waitFor();
}
// generate unique name
function uniqueName() {
var now = LocalDateTime.now().toString();
// replace unsafe chars with '_'
return "JavaShell" + now.replace(/-|:|\./g, '_');
}
// read-compile-run loop
while(true) {
var className = uniqueName();
if (generate(className)) {
exec("javac ${className}.java");
exec("java ${className}");
} else {
break;
}
}
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