New Expression: Free / Max / Total Memory (#5636)

src/main/java/ch/njol/skript/expressions/ExprMemory.java

@@ -0,0 +1,104 @@
+/**
+ *   This file is part of Skript.
+ *
+ *  Skript is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Skript is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with Skript.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright Peter Güttinger, SkriptLang team and contributors
+ */
+package ch.njol.skript.expressions;
+
+import java.util.Locale;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.util.SimpleExpression;
+import ch.njol.util.Kleenean;
+import ch.njol.util.coll.CollectionUtils;
+import org.bukkit.event.Event;
+import org.eclipse.jdt.annotation.Nullable;
+
+@Name("Free / Max / Total Memory")
+@Description("The free, max or total memory of the server in Megabytes.")
+@Examples({
+	"while player is online:",
+		"\tsend action bar \"Memory left: %free memory%/%max memory%MB\" to player",
+		"\twait 5 ticks"
+})
+@Since("INSERT VERSION")
+public class ExprMemory extends SimpleExpression<Double> {
+
+	private static final double BYTES_IN_MEGABYTES = 1E-6;
+	private static final Runtime RUNTIME = Runtime.getRuntime();
+
+	static {
+		Skript.registerExpression(ExprMemory.class, Double.class, ExpressionType.SIMPLE, "[the] [server] (:free|max:max[imum]|total) (memory|ram)");
+	}
+
+	private enum Type {
+		FREE, MAXIMUM, TOTAL
+	}
+
+	private Type type;
+
+	@Override
+	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		if (parseResult.hasTag("free")) {
+			type = Type.FREE;
+		} else if (parseResult.hasTag("max")) {
+			type = Type.MAXIMUM;
+		} else {
+			type = Type.TOTAL;
+		}
+		return true;
+	}
+
+	@Override
+	protected Double[] get(Event event) {
+		double memory = 0;
+		switch (type) {
+			case FREE:
+				memory = RUNTIME.freeMemory();
+				break;
+			case MAXIMUM:
+				memory = RUNTIME.maxMemory();
+				break;
+			case TOTAL:
+				memory = RUNTIME.totalMemory();
+				break;
+		}
+		return CollectionUtils.array(memory * BYTES_IN_MEGABYTES);
+	}
+
+	@Override
+	public boolean isSingle() {
+		return true;
+	}
+
+	@Override
+	public Class<? extends Double> getReturnType() {
+		return Double.class;
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return type.name().toLowerCase(Locale.ENGLISH) + " memory";
+	}
+
+}