Validity checks on NamespaceIDs

src/main/java/net/minestom/server/utils/NamespaceID.java

@@ -1,17 +1,18 @@
 package net.minestom.server.utils;
 
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Objects;
+import java.util.regex.Pattern;
 
 /**
  * Represents a namespaced ID
  * https://minecraft.gamepedia.com/Namespaced_ID
- * <p>
- * TODO: Implement validity conditions
  */
 public class NamespaceID implements CharSequence {
     private static final Int2ObjectOpenHashMap<NamespaceID> cache = new Int2ObjectOpenHashMap<>();
+    private static final String legalLetters = "[0123456789abcdefghijklmnopqrstuvwxyz_-]+";
 
     private final String domain;
     private final String path;
@@ -28,6 +29,7 @@ public class NamespaceID implements CharSequence {
         final int index = namespaceID.indexOf(':');
         if (index < 0)
             return "minecraft";
+        assert namespaceID.indexOf(':', index+1) == -1: "Namespace ID can only have at most one colon ':' ("+namespaceID+")";
         return namespaceID.substring(0, index);
     }
 
@@ -42,6 +44,7 @@ public class NamespaceID implements CharSequence {
         final int index = namespaceID.indexOf(':');
         if (index < 0)
             return namespaceID;
+        assert namespaceID.indexOf(':', index+1) == -1: "Namespace ID can only have at most one colon ':' ("+namespaceID+")";
         return namespaceID.substring(index + 1);
     }
 
@@ -68,12 +71,20 @@ public class NamespaceID implements CharSequence {
             this.path = path.substring(index + 1);
         }
         this.full = toString();
+        validate();
     }
 
     private NamespaceID(String domain, String path) {
         this.domain = domain;
         this.path = path;
         this.full = toString();
+        validate();
+    }
+
+    private void validate() {
+        assert !domain.contains(".") && !domain.contains("/") : "Domain cannot contain a dot nor a slash character (" + full+ ")";
+        assert domain.matches(legalLetters) : "Illegal character in domain ("+full+"). Must match "+legalLetters;
+        assert path.matches(legalLetters) : "Illegal character in path ("+full+"). Must match "+legalLetters;
     }
 
     public String getDomain() {
@@ -113,6 +124,7 @@ public class NamespaceID implements CharSequence {
         return full.subSequence(start, end);
     }
 
+    @NotNull
     @Override
     public String toString() {
         return domain + ":" + path;

src/test/java/misc/TestNamespaceIDValidity.java

@@ -0,0 +1,73 @@
+package misc;
+
+import net.minestom.server.utils.NamespaceID;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class TestNamespaceIDValidity {
+
+    @Test
+    public void noErrorWithCorrectFormat() {
+        NamespaceID.from("minecraft:any");
+    }
+
+    @Test
+    public void atMostOneColon() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft:block:wool");
+        });
+    }
+
+    @Test
+    public void noSlashInDomain() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft/java_edition:any");
+        });
+    }
+
+    @Test
+    public void noDotInDomain() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft.java:game");
+        });
+    }
+
+    @Test
+    public void noUppercase() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("Minecraft:any");
+        });
+
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft:Any");
+        });
+    }
+
+    @Test
+    public void noSpace() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft:a n y");
+        });
+    }
+
+    @Test
+    public void onlyLatinLowercase() {
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("Minecraft:voilà");
+        });
+
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft:où_ça");
+        });
+
+        assertThrows(AssertionError.class, () -> {
+            NamespaceID.from("minecraft:schrödingers_var");
+        });
+    }
+
+    @Test
+    public void numbersAllowed() {
+        NamespaceID.from("0xc1:468786471");
+    }
+}