Readline interface: Difference between revisions

=={{header|Java}}==

{{trans|C#}}

<lang java>import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.HashMap;

import java.util.LinkedList;

import java.util.Map;

public class ReadlineInterface {

private static LinkedList<String> histArr = new LinkedList<>();

private static void hist() {

if (histArr.isEmpty()) {

System.out.println("No history");

} else {

histArr.forEach(cmd -> System.out.printf(" - %s\n", cmd));

}

class Crutch {}

histArr.add(Crutch.class.getEnclosingMethod().getName());

}

private static void hello() {

System.out.println("Hello World!");

class Crutch {}

histArr.add(Crutch.class.getEnclosingMethod().getName());

}

private static void help() {

System.out.println("Available commands:");

System.out.println(" hello");

System.out.println(" hist");

System.out.println(" exit");

System.out.println(" help");

class Crutch {}

histArr.add(Crutch.class.getEnclosingMethod().getName());

}

public static void main(String[] args) throws IOException {

Map<String, Runnable> cmdMap = new HashMap<>();

cmdMap.put("help", ReadlineInterface::help);

cmdMap.put("hist", ReadlineInterface::hist);

cmdMap.put("hello", ReadlineInterface::hello);

BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

System.out.println("Enter a command, type help for a listing.");

while (true) {

System.out.print(">");

String line = in.readLine();

if ("exit".equals(line)) {

break;

}

cmdMap.getOrDefault(line, ReadlineInterface::help).run();

}

}

}</lang>