annotations.processor

This repository provides an annotation processor, that generates command dispatch classes for individual commands.

Commands

Commands consist of several possible paths. One path ends at exactly one method and is defined by its required types, including possible constraints. Each method that is considered as a path needs to have an @Endpoint annotation.

@Endpoint(priority=0)
public void multiply(@IntArg int a, @DoubleArg int b) {
  ...
}

@Endpoint(priority=1)
public void add(@IntArg(min=3) int a, DoubleArg int b) {
  ...
}

Compiling a command class containing methods like this results in a second class, that accepts a String[] and tries to find a matching path for this argument array. Example:

• {"2", "2.3"} can be matched only to the multiply method, therefore multiply(2, 2.3) is called.
• {"4", "2.3"} can be matched to both the multiply and the add method. Since add has a higher priority, add(4, 2.3) is called.
• {"3", "Test"} has no matching path. The dispatcher method returns false to signal that no path has been found.

Available annotations

@Endpoint

Used to mark paths for the dispatched.

Options:

• priority: Higher priority guarantees execution, when more than one path matches. Default: 0
• target: An array of CommandSource enums. Specifies which senders can call a command. Default: {CommandSender.PLAYER}

@IntArg

An argument of type int.

Options:

• min: The lowest allowed value. Default: Integer.MIN_VALUE
• max: The highest allowed value. Default: Integer.MAX_VALUE

@DoubleArg

An argument of type double.

Options:

• min: The lowest allowed value. Default: Double.MIN_VALUE
• max: The highest allowed value. Default: Double.MAX_VALUE
• allowNaN: If NaN is an allowed value. Default: false
• allowInfinity: If Infinity is an allowed value. Default: false

@StringArg

An argument of type String.

@LiteralArg

A literal string value. It's use can be best described by giving an example.

@Endpoint
public void copy(@LiteralArg(value="copy") String l, @StringArg String msg) {
  ...
}

• {"copy", "test.pdf"} can be matched only to the copy method, therefore copy("copy", "test.pdf") is called.
• {"delete", "taxes.txt"} can not be matched to any method.

Required:

• value: The literal string.

Optional:

• aliases: Allowed aliases of the literal string. Default: {}

Arrays

Every argument, except for @LiteralArg can be an array, if they are the last parameter of a method. The array consumes every following argument matching its constraints, and calls the method if all arguments were consumed successfully.

Custom annotations

Custom argument annotations can be created. These annotations must itself have the @Argument annotation.

Example maven config

<build> 
    <plugins>
        <plugin>
            <groupId>org.bsc.maven</groupId>
            <artifactId>maven-processor-plugin</artifactId>
            <version>2.2.4</version>
            <executions>
                <execution>
                    <id>process</id>
                    <goals>
                        <goal>process</goal>
                    </goals>
                    <configuration>
                        <processors>
                            <processor>com.spleefleague.annotations.processor.Processor</processor>
                        </processors>
                    </configuration>
                    <phase>generate-sources</phase>
                </execution>
            </executions>
            <dependencies>
                <dependency>
                    <groupId>com.spleefleague</groupId>
                    <artifactId>annotations.processor</artifactId>
                    <version>1.0</version>
                    <scope>compile</scope>
                    <optional>true</optional>
                </dependency>
            </dependencies>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <compilerArgument>-proc:none</compilerArgument>
            </configuration>
        </plugin>
    </plugins> 
</build>
<repositories>
    <repository>
        <id>spleefleague-maven</id>
        <name>spleefleague-maven</name>
        <url>https://maven.spleefleague.com</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>com.spleefleague</groupId>
        <artifactId>annotations</artifactId>
        <version>1.0</version>
    </dependency>
</dependencies>