Implements #16

api/src/main/java/net/islandearth/rpgregions/requirements/DependencyRequirement.java

@@ -0,0 +1,47 @@
+package net.islandearth.rpgregions.requirements;
+
+import com.google.common.collect.ImmutableList;
+import org.bukkit.entity.Player;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class DependencyRequirement extends RegionRequirement {
+    
+    private final List<String> requiredRegions;
+    
+    public DependencyRequirement(List<String> requiredRegions) {
+        this.requiredRegions = requiredRegions;
+    }
+    
+    /**
+     * Returns an immutable list of required regions by their ID.
+     * @return immutable list of required regions
+     */
+    public ImmutableList<String> getRequiredRegions() {
+        return ImmutableList.copyOf(requiredRegions);
+    }
+    
+    public boolean meetsRequirements(Player player, List<String> discoveries) {
+        for (String discovery : discoveries) {
+            if (!requiredRegions.contains(discovery)) return false;
+        }
+        return true;
+    }
+    
+    @Override
+    @Deprecated
+    public boolean meetsRequirements(Player player) {
+        return meetsRequirements(player, Arrays.asList());
+    }
+    
+    @Override
+    public String getName() {
+        return "Dependency";
+    }
+    
+    @Override
+    public String getText(Player player) {
+        return "regions " + String.join(", ", requiredRegions);
+    }
+}