1 files changed, 53 insertions, 0 deletions
diff --git a/src/org/unitConverter/unit/UnitSystem.java b/src/org/unitConverter/unit/UnitSystem.java
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+++ b/src/org/unitConverter/unit/UnitSystem.java
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+/**
+ * Copyright (C) 2018 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.unitConverter.unit;
+
+import java.util.Objects;
+
+import org.unitConverter.dimension.UnitDimension;
+
+/**
+ * A system of units. Each unit should be aware of its system.
+ * 
+ * @author Adrien Hopkins
+ * @since 2018-12-23
+ * @since v0.1.0
+ */
+public interface UnitSystem {
+	/**
+	 * Gets a base unit for this system and the provided dimension.
+	 * 
+	 * @param dimension
+	 *            dimension used by base unit
+	 * @return base unit
+	 * @throws NullPointerException
+	 *             if dimension is null
+	 * @since 2019-01-25
+	 * @since v0.1.0
+	 */
+	default BaseUnit getBaseUnit(final UnitDimension dimension) {
+		Objects.requireNonNull(dimension, "dimension must not be null.");
+		return new BaseUnit(dimension, this);
+	}
+
+	/**
+	 * @return name of system
+	 * @since 2018-12-23
+	 * @since v0.1.0
+	 */
+	String getName();
+}