README.md

Maven

<repositories>
    <repository>
        <id>opencollab-repo-snapshot</id>
        <url>https://repo.opencollab.dev/maven-snapshots</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>com.creeperface.nukkit.placeholderapi</groupId>
        <artifactId>PlaceholderAPI</artifactId>
        <version>1.4-SNAPSHOT</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

How to use

Obtaining PlaceholderAPI instance

PlaceholderAPI api = PlaceholderAPI.getInstance();

val api = PlaceholderAPI.getInstance()

Getting placeholder value

//player can be omitted unless it's a visitor based placeholder
api.getValue("placeholder_name", player);

To automatically replace all placeholder in a string use translateString() method

String result=api.translateString(inputString, player);

For kotlin there's an extension function

val result = inputString.translatePlaceholders(player)

Registering a new placeholder

There are two ways how placeholders are being processed Placeholders registered as static have the same value for all players which allows PAPI to effectively cache its value and increase overall performance

The second one is visitor based placeholder which depends on the player it is showing to In this case we always need to supply player instance to get the value

Simple example of static placeholder that returns current server tick:

api.builder("tick", Integer.class)
        .loader(entry -> Server.getInstance().getTick())
        .build();

In kotlin we use a slightly different syntax using DSL

api.build<Int>("tick") {
    loader {
        Server.getInstance().tick
    }
}

Simple example of visitor based placeholder that returns player name

api.builder("player_name", String.class)
        .visitorLoader(entry -> {
            return entry.getPlayer().getName();
        });

Kotlin DSL makes it easier so we can access player instance directly through the lambda receiver

api.build<String>("player_name") {
    visitorLoader {
        player.name
    }
}

Builder contains a few other options

api.builder("tick", Integer.class)
        .aliases("server_tick", "servertick") //placeholder aliases
        .autoUpdate(true) //enables auto update that triggers registered update listeners, disabled by default
        .updateInterval(10) //interval of auto update or cache clearing, disabled by default - no cache
        .loader(entry -> Server.getInstance().getTick())
        .build();

Parameters

Since 1.3 it is possible to use parameters in placeholder

For example consider placeholder which returns play time of a player called player_time Usage will look like this: %player_time<player_name>% where player_name is the name of player we want to get the time of

Simple example that returns player name and optionally converts it to lowercase The only difference is the processParameters() method that enables parameter processing

api.builder("player_name", String.class)
        .processParameters(true)
        .visitorLoader(entry -> {
            String name = entry.getPlayer().getName();
    
            Parameter parameter = entry.getParameters().single();
            if (parameter != null && parameter.getValue().equals("lc")) { //lowercase
                name = name.toLowerCase();
            }
    
            return name;
        });

api.build<String>("player_name") {
    processParameters(true)
    visitorLoader {
        parameters.single()?.let {
            if (it.value == "lc") { //lowercase
                return@visitorLoader player.name.toLowerCase()
            }
        }

        player.name
    }
}

Placeholder scopes

By default all placeholders belong to global scope The option of "subscopes" brings possibility of providing some specific data to placeholder which are used to output the value

By default PAPI contains a few scopes such as MessageScope and ChatScope and a few scoped placeholders such as %message% or %message_sender% where both are available only in MessageScope

Scope class is a singleton that represent scope in general Scope.Context class is something like a scope instance holding an actual scope argument

To get value from scoped placeholder we need to provide context instance. All methods including translateString() or getValue() contains optional vararg argument for contexts which defaults to GlobalScope It's possible to provide multiple different contexts since it's not restricted that message must contain placeholders only from a single scope The only current limitation is that placeholder can't use more than one scope, so the only solution to this is to extend another scope, or to create multiple placeholders

Example usage of ChatScope:

val messageTemplate = "%message_sender%: %message%"

fun onChat(e: PlayerChatEvent) {
    e.message = messageTemplate.translatePlaceholders(
        e.player,
        e.context //extension property for PlayerChatEvent
    )
}

This replaces both placeholders in message template These placeholders don't exist in GlobalScope, however they do in ChatScope

Another example of scopes is one I used in BedWars where I use 2 scopes ArenaScope - provides various placeholders related to arena TeamScope - provides placeholders related to team such as color, name, status

Both of them can be used in the configuration (armor color in team shop) as well, which makes everything easier imo :)