Unix data expression (#2675)

* Create ExprUnixDate.java

* Create ExprUnixDate.sk

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

@@ -0,0 +1,57 @@
+/**
+ *   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 2011-2017 Peter Güttinger and contributors
+ */
+package ch.njol.skript.expressions;
+
+import org.eclipse.jdt.annotation.Nullable;
+
+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.expressions.base.SimplePropertyExpression;
+import ch.njol.skript.util.Date;
+
+@Name("Unix Date")
+@Description("Converts given Unix timestamp to a date. The Unix timespan represents the number of seconds elapsed since 1 January 1970.")
+@Examples("unix date of 946684800 #1 January 2000 12:00 AM (UTC Time)")
+@Since("INSERT VERSION")
+public class ExprUnixDate extends SimplePropertyExpression<Number, Date> {
+
+	static {
+		register(ExprUnixDate.class, Date.class, "unix date", "numbers");
+	}
+
+	@Override
+	@Nullable
+	public Date convert(Number n) {
+		return new Date((long)(n.doubleValue() * 1000));
+	}
+
+	@Override
+	protected String getPropertyName() {
+		return "unix date";
+	}
+
+	@Override
+	public Class<? extends Date> getReturnType() {
+		return Date.class;
+	}
+
+}

src/test/skript/tests/syntaxes/expressions/ExprUnixDate.sk

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+test "unix date":
+	set {_now} to now
+	assert unix date of (unix timestamp of {_now}) is {_now} with "unix date failed"