EasyCLI

EasyCLI is a simple utility project that helps to parse commands in linux shell style in an annotation based way.

Build

mvn clean install

Usage

Maven

Add the dependency to your pom.xml:

<dependency>
    <groupId>at.apf.easycli</groupId>
    <artifactId>easy-cli</artifactId>
    <version>0.4</version>
</dependency>

Java

Hack the engine

CliEngine engine = new EasyEngine();

// Register a commands 
engine.register(new Object() {
    
    @Command("/add")
    int add(int a, int b) {
        return a + b;
    }
    
    @Command("/sort")
    int[] sort(@Flag('d') boolean desc, int[] arr) {
        if (desc)
            return this.sortDesc(arr);
        else
            return this.sortAsc(arr);
    }
    
    @Command("/send")
    void send(String receiver, @Optional String msg) {
        if (msg == null) {
            msg = "Hello";
        }
        this.sendMessage(receiver, msg);
    }
    
    @Command("/foo")
    int foo(@DefaultValue("9") int bar) {
        return bar;
    }
    
    @Command("/sendUser")
    void sendUser(String msg, @Meta User user) {
        this.sendMessage(user.getAddress(), msg);
    }
});

// Parse some command string and execute the registered implementation
int result = engine.parse("/add 2 3");            // 5
int[] sorted = engine.parse("/sort -d 7 9 2 78"); // 78 9 7 2
sorted = engine.parse("/sort 7 9 2 78");          // 2 7 9 78
engine.parse("/send alice \"Hi alice\"");         // Sends 'Hi alice' to alice
engine.parse("/send alice");                      // Sends 'Hello' to alice
engine.parse("/foo 1");                           // 1
engine.parse("/foo");                             // 9
engine.parse("/sendUser \"Hi Bob\"", 
        new User("Bob"));                         // Sends 'Hi Bob' to Bob

Supported Datatypes

• char
• int
• long
• float
• double
• boolean
• enum
• String
• Array (of one of the types above)

Hints

• @DefaultValue annotation accepts only a string but gets parsed to the needed type. So just insert the needed value in string representation.
• @DefaultValue "extends" @Optional. So you don't need to use both of them together.
• If the argument can't be parsed to the needed type, an exception is thrown.
• @Flag can only be annotated to boolean parameters and don't work together with @Optional or @DefaultValue.
• If a parameter is not annotated with the @Optional or @DefaultValue annotation and the argument in the command string is missing, an exception is thrown.
• The order of the arguments in the command have to be the same as in the defined implementation. Instead @Flag parameters can be arbitrary anywhere in the command.
• Flags can be set in the command with either "-a -b -c" or in one part ("-abc"). If a flag is set multiple times it does not affect anything. If the alternative is set inside a @Flag annotation, it can be used in the command with double minus (e.g. "--somelongername").
• Flags are not case-independet.
• @DefaultValue does not work for arrays.
• An array have to be at the end of the parameter definition and it is only at maximum one array allowed (else the parser does not know where one would end and the next one start).
• @Optional and @DefaultValue parameters have to be at the end of the parameter definition. After one of those annotations was set, all upcoming parameters have as well to be annotated with one of them.
• @Optional annotated parameters will be parsed to null if the argument is not set (also for arrays).
• @Meta parameters can be of any type.
• There is no limit of @Meta parameters. Just add them in the parse call as separated arguments.
• @Meta parameters can be combined with @Optional and @DefaultValue.
• @Usage can be used for commands and flag parameters

Changelog

v0.2

• Ignoring multiple spaces in the input command and handle them as a single one
• Introduced @Meta annotation to pass outstanding objects to the commands implementation.

v0.3

• enum support
• char support

v0.4

• Introduced @Usage annotation and CliEngine.listCommands() and CliEngine.usage(command) to describe registered commands.

TODOs

• allow default values for array
• Grouped Optionals