Related
I'm trying to redefine a method at runtime using javassist, but I'm running into some issues on the last step, because of the weird requirements I have for this:
I can't require the user to add startup flags
My code will necessarily run after the class has already been defined/loaded
My code looks like this:
val cp = ClassPool.getDefault()
val clazz = cp.get("net.minecraft.world.item.ItemStack")
val method = clazz.getDeclaredMethod(
"a",
arrayOf(cp.get("net.minecraft.world.level.block.state.IBlockData"))
)
method.setBody(
"""
{
double destroySpeed = this.c().a(this, $1);
if (this.s()) {
return destroySpeed * this.t().k("DestroySpeedMultiplier");
} else {
return destroySpeed;
}
}
""".trimIndent()
)
clazz.toClass(Items::class.java)
(I'm dealing with obfuscated method references, hence the weird names)
However, calling .toClass() causes an error as there are then two duplicate classes on the class loader - and to my knowledge there's no way to unload a single class.
My next port of call to update the class was to use the attach API and an agent, but that requires a startup flag to be added (on Java 9+, I'm running J17), which I can't do given my requirements. I have the same problem trying to load an agent on startup.
I have tried patching the server's jar file itself by using .toBytecode(), but I didn't manage to write the new class file to the jar - this method sounds promising, so it's absolutely on the table to restart the server after patching the jar.
Is there any way I can get this to work with my requirements? Or is there any alternative I can use to change a method's behavior?
What is a good way of parsing command line arguments in Java?
Check these out:
http://commons.apache.org/cli/
http://www.martiansoftware.com/jsap/
Or roll your own:
http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html
For instance, this is how you use commons-cli to parse 2 string arguments:
import org.apache.commons.cli.*;
public class Main {
public static void main(String[] args) throws Exception {
Options options = new Options();
Option input = new Option("i", "input", true, "input file path");
input.setRequired(true);
options.addOption(input);
Option output = new Option("o", "output", true, "output file");
output.setRequired(true);
options.addOption(output);
CommandLineParser parser = new DefaultParser();
HelpFormatter formatter = new HelpFormatter();
CommandLine cmd = null;//not a good practice, it serves it purpose
try {
cmd = parser.parse(options, args);
} catch (ParseException e) {
System.out.println(e.getMessage());
formatter.printHelp("utility-name", options);
System.exit(1);
}
String inputFilePath = cmd.getOptionValue("input");
String outputFilePath = cmd.getOptionValue("output");
System.out.println(inputFilePath);
System.out.println(outputFilePath);
}
}
usage from command line:
$> java -jar target/my-utility.jar -i asd
Missing required option: o
usage: utility-name
-i,--input <arg> input file path
-o,--output <arg> output file
Take a look at the more recent JCommander.
I created it. I’m happy to receive questions or feature requests.
I have been trying to maintain a list of Java CLI parsers.
Airline
Active Fork: https://github.com/rvesse/airline
argparse4j
argparser
args4j
clajr
cli-parser
CmdLn
Commandline
DocOpt.java
dolphin getopt
DPML CLI (Jakarta Commons CLI2 fork)
Dr. Matthias Laux
Jakarta Commons CLI
jargo
jargp
jargs
java-getopt
jbock
JCLAP
jcmdline
jcommander
jcommando
jewelcli (written by me)
JOpt simple
jsap
naturalcli
Object Mentor CLI article (more about refactoring and TDD)
parse-cmd
ritopt
Rop
TE-Code Command
picocli has ANSI colorized usage help and autocomplete
It is 2022, time to do better than Commons CLI... :-)
Should you build your own Java command line parser, or use a library?
Many small utility-like applications probably roll their own command line parsing to avoid the additional external dependency. picocli may be an interesting alternative.
Picocli is a modern library and framework for building powerful, user-friendly, GraalVM-enabled command line apps with ease. It lives in 1 source file so apps can include it as source to avoid adding a dependency.
It supports colors, autocompletion, subcommands, and more. Written in Java, usable from Groovy, Kotlin, Scala, etc.
Features:
Annotation based: declarative, avoids duplication and expresses programmer intent
Convenient: parse user input and run your business logic with one line of code
Strongly typed everything - command line options as well as positional parameters
POSIX clustered short options (<command> -xvfInputFile as well as <command> -x -v -f InputFile)
Fine-grained control: an arity model that allows a minimum, maximum and variable number of parameters, e.g, "1..*", "3..5"
Subcommands (can be nested to arbitrary depth)
Feature-rich: composable arg groups, splitting quoted args, repeatable subcommands, and many more
User-friendly: usage help message uses colors to contrast important elements like option names from the rest of the usage help to reduce the cognitive load on the user
Distribute your app as a GraalVM native image
Works with Java 5 and higher
Extensive and meticulous documentation
The usage help message is easy to customize with annotations (without programming). For example:
(source)
I couldn't resist adding one more screenshot to show what usage help messages are possible. Usage help is the face of your application, so be creative and have fun!
Disclaimer: I created picocli. Feedback or questions very welcome.
Someone pointed me to args4j lately which is annotation based. I really like it!
I've used JOpt and found it quite handy: http://jopt-simple.sourceforge.net/
The front page also provides a list of about 8 alternative libraries, check them out and pick the one that most suits your needs.
I know most people here are going to find 10 million reasons why they dislike my way, but nevermind. I like to keep things simple, so I just separate the key from the value using a '=' and store them in a HashMap like this:
Map<String, String> argsMap = new HashMap<>();
for (String arg: args) {
String[] parts = arg.split("=");
argsMap.put(parts[0], parts[1]);
}
You could always maintain a list with the arguments you are expecting, to help the user in case he forgot an argument or used a wrong one... However, if you want too many features this solution is not for you anyway.
This is Google's command line parsing library open-sourced as part of the Bazel project. Personally I think it's the best one out there, and far easier than Apache CLI.
https://github.com/pcj/google-options
Installation
Bazel
maven_jar(
name = "com_github_pcj_google_options",
artifact = "com.github.pcj:google-options:jar:1.0.0",
sha1 = "85d54fe6771e5ff0d54827b0a3315c3e12fdd0c7",
)
Gradle
dependencies {
compile 'com.github.pcj:google-options:1.0.0'
}
Maven
<dependency>
<groupId>com.github.pcj</groupId>
<artifactId>google-options</artifactId>
<version>1.0.0</version>
</dependency>
Usage
Create a class that extends OptionsBase and defines your #Option(s).
package example;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionsBase;
import java.util.List;
/**
* Command-line options definition for example server.
*/
public class ServerOptions extends OptionsBase {
#Option(
name = "help",
abbrev = 'h',
help = "Prints usage info.",
defaultValue = "true"
)
public boolean help;
#Option(
name = "host",
abbrev = 'o',
help = "The server host.",
category = "startup",
defaultValue = ""
)
public String host;
#Option(
name = "port",
abbrev = 'p',
help = "The server port.",
category = "startup",
defaultValue = "8080"
)
public int port;
#Option(
name = "dir",
abbrev = 'd',
help = "Name of directory to serve static files.",
category = "startup",
allowMultiple = true,
defaultValue = ""
)
public List<String> dirs;
}
Parse the arguments and use them.
package example;
import com.google.devtools.common.options.OptionsParser;
import java.util.Collections;
public class Server {
public static void main(String[] args) {
OptionsParser parser = OptionsParser.newOptionsParser(ServerOptions.class);
parser.parseAndExitUponError(args);
ServerOptions options = parser.getOptions(ServerOptions.class);
if (options.host.isEmpty() || options.port < 0 || options.dirs.isEmpty()) {
printUsage(parser);
return;
}
System.out.format("Starting server at %s:%d...\n", options.host, options.port);
for (String dirname : options.dirs) {
System.out.format("\\--> Serving static files at <%s>\n", dirname);
}
}
private static void printUsage(OptionsParser parser) {
System.out.println("Usage: java -jar server.jar OPTIONS");
System.out.println(parser.describeOptions(Collections.<String, String>emptyMap(),
OptionsParser.HelpVerbosity.LONG));
}
}
https://github.com/pcj/google-options
Take a look at the Commons CLI project, lots of good stuff in there.
Yeap.
I think you're looking for something like this:
http://commons.apache.org/cli
The Apache Commons CLI library provides an API for processing command line interfaces.
If you are already using Spring Boot, argument parsing comes out of the box.
If you want to run something after startup, implement the ApplicationRunner interface:
#SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
#Override
public void run(ApplicationArguments args) {
args.containsOption("my-flag-option"); // test if --my-flag-option was set
args.getOptionValues("my-option"); // returns values of --my-option=value1 --my-option=value2
args.getOptionNames(); // returns a list of all available options
// do something with your args
}
}
Your run method will be invoked after the context has started up successfully.
If you need access to the arguments before you fire up your application context, you can just simply parse the application arguments manually:
#SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
ApplicationArguments arguments = new DefaultApplicationArguments(args);
// do whatever you like with your arguments
// see above ...
SpringApplication.run(Application.class, args);
}
}
And finally, if you need access to your arguments in a bean, just inject the ApplicationArguments:
#Component
public class MyBean {
#Autowired
private ApplicationArguments arguments;
// ...
}
Maybe these
JArgs command line option parsing
suite for Java - this tiny project provides a convenient, compact, pre-packaged and comprehensively documented suite of command line option parsers for the use of Java programmers. Initially, parsing compatible with GNU-style 'getopt' is provided.
ritopt, The Ultimate Options Parser for Java - Although, several command line option standards have been preposed, ritopt follows the conventions prescribed in the opt package.
I wrote another one: http://argparse4j.sourceforge.net/
Argparse4j is a command line argument parser library for Java, based on Python's argparse.
If you are familiar with gnu getopt, there is a Java port at: http://www.urbanophile.com/arenn/hacking/download.htm.
There appears to be a some classes that do this:
http://docs.sun.com/source/816-5618-10/netscape/ldap/util/GetOpt.html
http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/xsltc/cmdline/getopt/GetOpt.html
airline # Github looks good. It is based on annotation and is trying to emulate Git command line structures.
Argparse4j is best I have found. It mimics Python's argparse libary which is very convenient and powerful.
I want to show you my implementation: ReadyCLI
Advantages:
for lazy programmers: a very small number of classes to learn, just see the two small examples on the README in the repository and you are already at 90% of learning; just start coding your CLI/Parser without any other knowledge;
ReadyCLI allows coding CLIs in the most natural way;
it is designed with Developer Experience in mind; it largely uses the Builder design pattern and functional interfaces for Lambda Expressions, to allow a very quick coding;
it supports Options, Flags and Sub-Commands;
it allows to parse arguments from command-line and to build more complex and interactive CLIs;
a CLI can be started on Standard I/O just as easily as on any other I/O interface, such as sockets;
it gives great support for documentation of commands.
I developed this project as I needed new features (options, flag, sub-commands) and that could be used in the simplest possible way in my projects.
If you want something lightweight (jar size ~ 20 kb) and simple to use, you can try argument-parser. It can be used in most of the use cases, supports specifying arrays in the argument and has no dependency on any other library. It works for Java 1.5 or above. Below excerpt shows an example on how to use it:
public static void main(String[] args) {
String usage = "--day|-d day --mon|-m month [--year|-y year][--dir|-ds directoriesToSearch]";
ArgumentParser argParser = new ArgumentParser(usage, InputData.class);
InputData inputData = (InputData) argParser.parse(args);
showData(inputData);
new StatsGenerator().generateStats(inputData);
}
More examples can be found here
As one of the comments mentioned earlier (https://github.com/pcj/google-options) would be a good choice to start with.
One thing I want to add-on is:
1) If you run into some parser reflection error, please try use a newer version of the guava. in my case:
maven_jar(
name = "com_google_guava_guava",
artifact = "com.google.guava:guava:19.0",
server = "maven2_server",
)
maven_jar(
name = "com_github_pcj_google_options",
artifact = "com.github.pcj:google-options:jar:1.0.0",
server = "maven2_server",
)
maven_server(
name = "maven2_server",
url = "http://central.maven.org/maven2/",
)
2) When running the commandline:
bazel run path/to/your:project -- --var1 something --var2 something -v something
3) When you need the usage help, just type:
bazel run path/to/your:project -- --help
Take a look at Spring Shell
Spring Shell’s features include
A simple, annotation driven, programming model to contribute custom commands
Use of Spring Boot auto-configuration functionality as the basis for a command plugin strategy
Tab completion, colorization, and script execution
Customization of command prompt, shell history file name, handling of results and errors
Dynamic enablement of commands based on domain specific criteria
Integration with the bean validation API
Already built-in commands, such as clear screen, gorgeous help, exit
ASCII art Tables, with formatting, alignment, fancy borders, etc.
For Spring users, we should mention also https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/SimpleCommandLinePropertySource.html and his twin brother https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/JOptCommandLinePropertySource.html (JOpt implementation of the same functionality).
The advantage in Spring is that you can directly bind the command line arguments to attributes, there is an example here https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/CommandLinePropertySource.html
What is a good way of parsing command line arguments in Java?
Check these out:
http://commons.apache.org/cli/
http://www.martiansoftware.com/jsap/
Or roll your own:
http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html
For instance, this is how you use commons-cli to parse 2 string arguments:
import org.apache.commons.cli.*;
public class Main {
public static void main(String[] args) throws Exception {
Options options = new Options();
Option input = new Option("i", "input", true, "input file path");
input.setRequired(true);
options.addOption(input);
Option output = new Option("o", "output", true, "output file");
output.setRequired(true);
options.addOption(output);
CommandLineParser parser = new DefaultParser();
HelpFormatter formatter = new HelpFormatter();
CommandLine cmd = null;//not a good practice, it serves it purpose
try {
cmd = parser.parse(options, args);
} catch (ParseException e) {
System.out.println(e.getMessage());
formatter.printHelp("utility-name", options);
System.exit(1);
}
String inputFilePath = cmd.getOptionValue("input");
String outputFilePath = cmd.getOptionValue("output");
System.out.println(inputFilePath);
System.out.println(outputFilePath);
}
}
usage from command line:
$> java -jar target/my-utility.jar -i asd
Missing required option: o
usage: utility-name
-i,--input <arg> input file path
-o,--output <arg> output file
Take a look at the more recent JCommander.
I created it. I’m happy to receive questions or feature requests.
I have been trying to maintain a list of Java CLI parsers.
Airline
Active Fork: https://github.com/rvesse/airline
argparse4j
argparser
args4j
clajr
cli-parser
CmdLn
Commandline
DocOpt.java
dolphin getopt
DPML CLI (Jakarta Commons CLI2 fork)
Dr. Matthias Laux
Jakarta Commons CLI
jargo
jargp
jargs
java-getopt
jbock
JCLAP
jcmdline
jcommander
jcommando
jewelcli (written by me)
JOpt simple
jsap
naturalcli
Object Mentor CLI article (more about refactoring and TDD)
parse-cmd
ritopt
Rop
TE-Code Command
picocli has ANSI colorized usage help and autocomplete
It is 2022, time to do better than Commons CLI... :-)
Should you build your own Java command line parser, or use a library?
Many small utility-like applications probably roll their own command line parsing to avoid the additional external dependency. picocli may be an interesting alternative.
Picocli is a modern library and framework for building powerful, user-friendly, GraalVM-enabled command line apps with ease. It lives in 1 source file so apps can include it as source to avoid adding a dependency.
It supports colors, autocompletion, subcommands, and more. Written in Java, usable from Groovy, Kotlin, Scala, etc.
Features:
Annotation based: declarative, avoids duplication and expresses programmer intent
Convenient: parse user input and run your business logic with one line of code
Strongly typed everything - command line options as well as positional parameters
POSIX clustered short options (<command> -xvfInputFile as well as <command> -x -v -f InputFile)
Fine-grained control: an arity model that allows a minimum, maximum and variable number of parameters, e.g, "1..*", "3..5"
Subcommands (can be nested to arbitrary depth)
Feature-rich: composable arg groups, splitting quoted args, repeatable subcommands, and many more
User-friendly: usage help message uses colors to contrast important elements like option names from the rest of the usage help to reduce the cognitive load on the user
Distribute your app as a GraalVM native image
Works with Java 5 and higher
Extensive and meticulous documentation
The usage help message is easy to customize with annotations (without programming). For example:
(source)
I couldn't resist adding one more screenshot to show what usage help messages are possible. Usage help is the face of your application, so be creative and have fun!
Disclaimer: I created picocli. Feedback or questions very welcome.
Someone pointed me to args4j lately which is annotation based. I really like it!
I've used JOpt and found it quite handy: http://jopt-simple.sourceforge.net/
The front page also provides a list of about 8 alternative libraries, check them out and pick the one that most suits your needs.
I know most people here are going to find 10 million reasons why they dislike my way, but nevermind. I like to keep things simple, so I just separate the key from the value using a '=' and store them in a HashMap like this:
Map<String, String> argsMap = new HashMap<>();
for (String arg: args) {
String[] parts = arg.split("=");
argsMap.put(parts[0], parts[1]);
}
You could always maintain a list with the arguments you are expecting, to help the user in case he forgot an argument or used a wrong one... However, if you want too many features this solution is not for you anyway.
This is Google's command line parsing library open-sourced as part of the Bazel project. Personally I think it's the best one out there, and far easier than Apache CLI.
https://github.com/pcj/google-options
Installation
Bazel
maven_jar(
name = "com_github_pcj_google_options",
artifact = "com.github.pcj:google-options:jar:1.0.0",
sha1 = "85d54fe6771e5ff0d54827b0a3315c3e12fdd0c7",
)
Gradle
dependencies {
compile 'com.github.pcj:google-options:1.0.0'
}
Maven
<dependency>
<groupId>com.github.pcj</groupId>
<artifactId>google-options</artifactId>
<version>1.0.0</version>
</dependency>
Usage
Create a class that extends OptionsBase and defines your #Option(s).
package example;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionsBase;
import java.util.List;
/**
* Command-line options definition for example server.
*/
public class ServerOptions extends OptionsBase {
#Option(
name = "help",
abbrev = 'h',
help = "Prints usage info.",
defaultValue = "true"
)
public boolean help;
#Option(
name = "host",
abbrev = 'o',
help = "The server host.",
category = "startup",
defaultValue = ""
)
public String host;
#Option(
name = "port",
abbrev = 'p',
help = "The server port.",
category = "startup",
defaultValue = "8080"
)
public int port;
#Option(
name = "dir",
abbrev = 'd',
help = "Name of directory to serve static files.",
category = "startup",
allowMultiple = true,
defaultValue = ""
)
public List<String> dirs;
}
Parse the arguments and use them.
package example;
import com.google.devtools.common.options.OptionsParser;
import java.util.Collections;
public class Server {
public static void main(String[] args) {
OptionsParser parser = OptionsParser.newOptionsParser(ServerOptions.class);
parser.parseAndExitUponError(args);
ServerOptions options = parser.getOptions(ServerOptions.class);
if (options.host.isEmpty() || options.port < 0 || options.dirs.isEmpty()) {
printUsage(parser);
return;
}
System.out.format("Starting server at %s:%d...\n", options.host, options.port);
for (String dirname : options.dirs) {
System.out.format("\\--> Serving static files at <%s>\n", dirname);
}
}
private static void printUsage(OptionsParser parser) {
System.out.println("Usage: java -jar server.jar OPTIONS");
System.out.println(parser.describeOptions(Collections.<String, String>emptyMap(),
OptionsParser.HelpVerbosity.LONG));
}
}
https://github.com/pcj/google-options
Take a look at the Commons CLI project, lots of good stuff in there.
Yeap.
I think you're looking for something like this:
http://commons.apache.org/cli
The Apache Commons CLI library provides an API for processing command line interfaces.
If you are already using Spring Boot, argument parsing comes out of the box.
If you want to run something after startup, implement the ApplicationRunner interface:
#SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
#Override
public void run(ApplicationArguments args) {
args.containsOption("my-flag-option"); // test if --my-flag-option was set
args.getOptionValues("my-option"); // returns values of --my-option=value1 --my-option=value2
args.getOptionNames(); // returns a list of all available options
// do something with your args
}
}
Your run method will be invoked after the context has started up successfully.
If you need access to the arguments before you fire up your application context, you can just simply parse the application arguments manually:
#SpringBootApplication
public class Application implements ApplicationRunner {
public static void main(String[] args) {
ApplicationArguments arguments = new DefaultApplicationArguments(args);
// do whatever you like with your arguments
// see above ...
SpringApplication.run(Application.class, args);
}
}
And finally, if you need access to your arguments in a bean, just inject the ApplicationArguments:
#Component
public class MyBean {
#Autowired
private ApplicationArguments arguments;
// ...
}
Maybe these
JArgs command line option parsing
suite for Java - this tiny project provides a convenient, compact, pre-packaged and comprehensively documented suite of command line option parsers for the use of Java programmers. Initially, parsing compatible with GNU-style 'getopt' is provided.
ritopt, The Ultimate Options Parser for Java - Although, several command line option standards have been preposed, ritopt follows the conventions prescribed in the opt package.
I wrote another one: http://argparse4j.sourceforge.net/
Argparse4j is a command line argument parser library for Java, based on Python's argparse.
If you are familiar with gnu getopt, there is a Java port at: http://www.urbanophile.com/arenn/hacking/download.htm.
There appears to be a some classes that do this:
http://docs.sun.com/source/816-5618-10/netscape/ldap/util/GetOpt.html
http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/xsltc/cmdline/getopt/GetOpt.html
airline # Github looks good. It is based on annotation and is trying to emulate Git command line structures.
Argparse4j is best I have found. It mimics Python's argparse libary which is very convenient and powerful.
I want to show you my implementation: ReadyCLI
Advantages:
for lazy programmers: a very small number of classes to learn, just see the two small examples on the README in the repository and you are already at 90% of learning; just start coding your CLI/Parser without any other knowledge;
ReadyCLI allows coding CLIs in the most natural way;
it is designed with Developer Experience in mind; it largely uses the Builder design pattern and functional interfaces for Lambda Expressions, to allow a very quick coding;
it supports Options, Flags and Sub-Commands;
it allows to parse arguments from command-line and to build more complex and interactive CLIs;
a CLI can be started on Standard I/O just as easily as on any other I/O interface, such as sockets;
it gives great support for documentation of commands.
I developed this project as I needed new features (options, flag, sub-commands) and that could be used in the simplest possible way in my projects.
If you want something lightweight (jar size ~ 20 kb) and simple to use, you can try argument-parser. It can be used in most of the use cases, supports specifying arrays in the argument and has no dependency on any other library. It works for Java 1.5 or above. Below excerpt shows an example on how to use it:
public static void main(String[] args) {
String usage = "--day|-d day --mon|-m month [--year|-y year][--dir|-ds directoriesToSearch]";
ArgumentParser argParser = new ArgumentParser(usage, InputData.class);
InputData inputData = (InputData) argParser.parse(args);
showData(inputData);
new StatsGenerator().generateStats(inputData);
}
More examples can be found here
As one of the comments mentioned earlier (https://github.com/pcj/google-options) would be a good choice to start with.
One thing I want to add-on is:
1) If you run into some parser reflection error, please try use a newer version of the guava. in my case:
maven_jar(
name = "com_google_guava_guava",
artifact = "com.google.guava:guava:19.0",
server = "maven2_server",
)
maven_jar(
name = "com_github_pcj_google_options",
artifact = "com.github.pcj:google-options:jar:1.0.0",
server = "maven2_server",
)
maven_server(
name = "maven2_server",
url = "http://central.maven.org/maven2/",
)
2) When running the commandline:
bazel run path/to/your:project -- --var1 something --var2 something -v something
3) When you need the usage help, just type:
bazel run path/to/your:project -- --help
Take a look at Spring Shell
Spring Shell’s features include
A simple, annotation driven, programming model to contribute custom commands
Use of Spring Boot auto-configuration functionality as the basis for a command plugin strategy
Tab completion, colorization, and script execution
Customization of command prompt, shell history file name, handling of results and errors
Dynamic enablement of commands based on domain specific criteria
Integration with the bean validation API
Already built-in commands, such as clear screen, gorgeous help, exit
ASCII art Tables, with formatting, alignment, fancy borders, etc.
For Spring users, we should mention also https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/SimpleCommandLinePropertySource.html and his twin brother https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/JOptCommandLinePropertySource.html (JOpt implementation of the same functionality).
The advantage in Spring is that you can directly bind the command line arguments to attributes, there is an example here https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/env/CommandLinePropertySource.html
Hello I am trying to pass arguments to my ImageJ PlugIn. However it seems no matter what I pass, argument string will be considered as empty by the program. I couldn't find any documentation on the internet about THAT issue.
My Java plugIn looks like this, and compiles fine.
import ij.plugin.PlugIn;
public class Test implements PlugIn {
public void run(String args) {
IJ.log("Starting plugin Test");
IJ.log("args: ." + args + ".");
}
}
I compile, make a .jar file and put it into the ImageJ plugins folder.
I can call it with the ImageJ userInterface (Plugin>Segmentation>Test) and the macro recorder will put the command used:
run("Test");
Then my code is executed, the log window pops-up as expected:
Starting plugin Test
args: ..
I can manually run the same command in a .ijm file, and get the same result.
However, when I run the following macro command:
run("Test", "my_string");
I get the same results in the log window:
Starting plugin Test
args: .. // <- I would like to get "my_string" passed there
Where it should have displayed (at least what I expect it to do)
Starting plugin Test
args: .my_string.
So my question is: how can I pass parameters to PlugIn and especially how to access them?
Many thanks
EDIT
Hey I found a way to bypass that:
Using the Macro.getOptions() : this method will retrieve the string passed in argument to the plugin.
However, I still can't find a way to pass more than 1 string argument. I tried overloading the PlugIn.run() method but it doesn't work at all.
My quick fix is to put all my arguments in 1 string, and separating them by a space. Then I split this string:
String [] arguments = Macro.getOptions().split(" ");
I don't see a more convenient way to get around that. I can't believe how stupid this situation is.
Please, if you have a better solution, feel free to share! Thanks
You are confusing the run(String arg) method in ij.plugin.Plugin with the ImageJ macro command run("command"\[, "options"\]), which calls IJ.run(String command, String options).
In the documentation for ij.plugin.Plugin#run(String arg), it says:
This method is called when the plugin is loaded. 'arg', which may be blank, is the argument specified for this plugin in IJ_Props.txt.
So, arg is an optional argument that you can use in IJ_Props.txt or in the plugins.config file of your plugin to assign different menu commands to different functions of your plugin (see also the excellent documentation on the Fiji wiki).
To make use of the options parameter when running your plugin from macro code, you should use a GenericDialog to get the options, or (as you apparently learned the hard way) use the helper function Macro.getOptions().
I have this Java enum:
public enum Commands
{
RESIZE_WINDOW("size -size"),
CREATE_CHARACTER("create-char -name"),
NEW_SCENE("scene -image"),
DIALOG("d -who -words"),
PLAY_SOUND("sound -file --blocking=false"),
FADE_TO("fade-to -file"),
WAIT("w -length=auto");
}
I want to be able to parse those strings and extract:
command name (e.g. create-char)
required parameters (e.g. -name)
optional options, with default value (e.g. --blocking=false)
I looked at org.apache.commons.cli, but that appears to fail on the first criteria (different command names) and is very verbose.
Any library suggestions?
(This is going to be used to parse a scripting "language", if that context helps.)
Edit: An example input in the scripting language would be d John "Hello World" -- multi-word text goes in quotes.
It appears that you want to build numerous CLI commands based simply on their "help descriptors"; a DSL of sorts. Instead of doing this string parsing, consider building the commands programmatically, for which there are numerous libraries (CLI being but one) and advantages.
Your example is already significantly complex enough that a second look at CLI (or one of the others) is warranted. You show required and optional args, each having either no-value or a default (though no means of indicating 'required' arg-values without a default, command descriptions, etc), and you still need to build a parser for the command line itself, verification, means of invoking handlers, etc...
Below is a list of command parsers I've found. None will parse your specific DSL, but they will allow you to build your commands programmatically, parse it, often verify and provide meaningful warnings, help handling, etc. Some even use annotations on objects to define commands, theoretically making maintenance easier.
Most are designed (and show examples) for parsing the arguments to your program, rather than numerous commands (natural-cli being an exception) but all should be able to do this - a simple class could wrap the parsing and options together:
static class CommandLine {
HashMap<String,Options> options = new HashMap<String,Options>();
public void register(String cmd, Options opts) {
options.put(cmd, opts);
}
public void parse(String line) {
// a better parser here would handle quoted strings
String[] split = line.split("\\s");
String cmd = split[0];
String[] args = new String[split.length-1];
if (args.length > 0)
System.arraycopy(split, 1, args, 0, args.length);
Options opts = options.get(cmd);
if (opts == null)
; // handle unknown command
else {
opts.parse(args);
// handle results...
opts.reset(); // required?
}
}
}
public static void main(String[] args) throws Exception {
CommandLine cl = new CommandLine();
cl.register("size", new Options()); // This will vary based on library Some
cl.register("create-char", new Options()); // require subclasses, others use builder
//... pattern, or other means.
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
while (true) {
cl.parse(in.readLine());
}
}
Other Libraries
CLI
JewelCli: also uses annotations, and allows lists and enums for values. examples look promising
natural-cli: allows cli with "human readable sentances". Seems geared towards your goal of multiple commands and their options, albiet with a different DSL and syntax.
GNU Java Getopt: Used same way as above, though you initialize the Getopt object with the name of the command.
JOpt Simple: Claims "simplicity over all others"
JArgs
args4j: uses annotations on separate classes created for each command
JSAP
CLAJR: uses reflection
CmdLn
ArgParser
JCommando: uses XML config files.
parse-cmd: uses Builder-pattern and method chaining to build parameters
cli-parser: annotation based