Simple Java program to tokenize string as a shell would - similar to shlex in Python. Not checked for POSIX compliance yet - feel free to comment with edge cases that could be fixed. This is my original work, free to reuse. Created for Stack Overflow question: https://stackoverflow.com/questions/1082953/shlex-alternative-for-java/20725050:

ShellSplitter.java

package com.cadrlife;

import java.util.ArrayList;
import java.util.List;

public class ShellSplitter {
    public List<String> shellSplit(CharSequence string) {
        List<String> tokens = new ArrayList<String>();
        boolean escaping = false;
        char quoteChar = ' ';
        boolean quoting = false;
        int lastCloseQuoteIndex = Integer.MIN_VALUE;
        StringBuilder current = new StringBuilder();
        for (int i = 0; i<string.length(); i++) {
            char c = string.charAt(i);
            if (escaping) {
                current.append(c);
                escaping = false;
            } else if (c == '\\' && !(quoting && quoteChar == '\'')) {
                escaping = true;
            } else if (quoting && c == quoteChar) {
                quoting = false;
                lastCloseQuoteIndex = i;
            } else if (!quoting && (c == '\'' || c == '"')) {
                quoting = true;
                quoteChar = c;
            } else if (!quoting && Character.isWhitespace(c)) {
                if (current.length() > 0 || lastCloseQuoteIndex == (i - 1)) {
                    tokens.add(current.toString());
                    current = new StringBuilder();
                }
            } else {
                current.append(c);
            }
        }
        if (current.length() > 0 || lastCloseQuoteIndex == (string.length() - 1)) {
            tokens.add(current.toString());
        }

        return tokens;
    }
}

ShellSplitterTest.java

package com.cadrlife;


import org.junit.Test;

import java.util.Arrays;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class ShellSplitterTest {
    ShellSplitter token = new ShellSplitter();
    @Test
    public void blankYieldsEmptyArgs() {
        assertTrue(token.shellSplit("").isEmpty());
    }

    @Test
    public void whitespacesOnlyYeildsEmptyArgs() {
        assertTrue(token.shellSplit("  \t \n").isEmpty());
    }

    @Test
    public void normalTokens() {
        assertEquals(Arrays.asList("a", "bee", "cee"), token.shellSplit("a\tbee  cee"));
    }

    @Test
    public void doubleQuotes() {
        assertEquals(Arrays.asList("hello world"), token.shellSplit("\"hello world\""));
    }

    @Test
    public void singleQuotes() {
        assertEquals(Arrays.asList("hello world"), token.shellSplit("'hello world'"));
    }

    @Test
    public void escapedDoubleQuotes() {
        assertEquals(Arrays.asList("\"hello world\""), token.shellSplit("\"\\\"hello world\\\""));
    }

    @Test
    public void noEscapeWithinSingleQuotes() {
        assertEquals(Arrays.asList("hello \\\" world"), token.shellSplit("'hello \\\" world'"));
    }

    @Test
    public void backToBackQuotedStringsShouldFormSingleToken() {
        assertEquals(Arrays.asList("foobarbaz"), token.shellSplit("\"foo\"'bar'baz"));
        assertEquals(Arrays.asList("three four"), token.shellSplit("\"three\"' 'four"));
    }

    @Test
    public void escapedSpacesDoNotBreakUpTokens() {
        assertEquals(Arrays.asList("three four"), token.shellSplit("three\\ four"));
    }

    @Test
    public void emptyDoubleQuotesYieldsListOfEmptyString() {
        assertEquals(Arrays.asList(""), token.shellSplit("\"\""));
    }

    @Test
    public void emptySingleQuotesYieldsListOfEmptyString() {
        assertEquals(Arrays.asList(""), token.shellSplit("''"));
    }

    @Test
    public void twoPairsEmptySingleQuotesYieldsListOfTwoEmptyStringWhenSeparated() {
        assertEquals(Arrays.asList("", ""), token.shellSplit("'' ''"));
    }

    @Test
    public void twoPairsEmptySingleQuotesYieldsListOfOneEmptyStringWhenNotSeparated() {
        assertEquals(Arrays.asList(""), token.shellSplit("''''"));
    }
}

UNLICENSE

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org/>

Would it be possible to upload this project to maven central?

Would it be possible to upload this project to maven central?

@ll01: I'm not opposed, but it seems like a lot of overhead to have people bring in an entire jar for 30 lines. If it were expanded to be a full port of Shlex that might run around 200 though, more than one might want to copy-paste. Or maybe there's an existing library that it'd make sense to contribute to.

Can you tell me more about your use case?

@raymyers its used to automate the prosses of giving SSL certs in our company. I was only saying this simply because if I'm calling it once or twice it would be easier to edit the pom, than copy and paste the function and the unit tests (our pipeline will fail the build if under a certain amount of line coverage). Also, I noticed I was using an outdated version of the gist having it as a maven jar would give a better chance of me seeing it was out of date. It's not that important if you want to leave it I'm cool.