TypeSafeConstant siblings: use Map.computeIfAbsent in getConstant

code/src/java/pcgen/cdom/enumeration/DisplayLocation.java

@@ -101,13 +101,7 @@ public String getComparisonString()
 	 */
 	public static DisplayLocation getConstant(String name)
 	{
-		DisplayLocation type = typeMap.get(name);
-		if (type == null)
-		{
-			type = new DisplayLocation(name);
-			typeMap.put(name, type);
-		}
-		return type;
+		return typeMap.computeIfAbsent(name, k -> new DisplayLocation(name));
 	}
 
 	/**

code/src/java/pcgen/cdom/enumeration/Region.java

@@ -99,13 +99,7 @@ public int getOrdinal()
 	public static Region getConstant(String name)
 	{
 		initializeTypeMap();
-		Region region = typeMap.get(name);
-		if (region == null)
-		{
-			region = new Region(name);
-			typeMap.put(name, region);
-		}
-		return region;
+		return typeMap.computeIfAbsent(name, k -> new Region(name));
 	}
 
 	/**

code/src/java/pcgen/cdom/enumeration/Type.java

@@ -172,13 +172,7 @@ public String getComparisonString()
 	 */
 	public static Type getConstant(String name)
 	{
-		Type type = TYPE_MAP.get(name);
-		if (type == null)
-		{
-			type = new Type(name);
-			TYPE_MAP.put(name, type);
-		}
-		return type;
+		return TYPE_MAP.computeIfAbsent(name, k -> new Type(name));
 	}
 
 	/**

code/src/test/pcgen/cdom/enumeration/DisplayLocationTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2026 (C) Vest <Vest@users.noreply.github.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 2.1 of the License, or (at your option)
+ * any later version.
+ *
+ * This library 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 Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+package pcgen.cdom.enumeration;
+
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Pins the intern contract of {@link DisplayLocation#getConstant(String)} and
+ * the strict lookup of {@link DisplayLocation#valueOf(String)}.
+ *
+ * Fixture names are namespaced ("DisplayLocationTest_*") to avoid colliding
+ * with data-load fixtures registered by other tests sharing the JVM.
+ */
+class DisplayLocationTest
+{
+
+	/** Two calls with the same name return the same interned instance. */
+	@Test
+	void getConstantInternsByName()
+	{
+		assertSame(DisplayLocation.getConstant("DisplayLocationTest_Alpha"),
+			DisplayLocation.getConstant("DisplayLocationTest_Alpha"));
+	}
+
+	/** The intern map is case-insensitive (CaseInsensitiveMap). */
+	@Test
+	void getConstantInternsCaseInsensitively()
+	{
+		assertSame(DisplayLocation.getConstant("DisplayLocationTest_Beta"),
+			DisplayLocation.getConstant("displaylocationtest_beta"));
+	}
+
+	/** Distinct names produce distinct instances. */
+	@Test
+	void getConstantDistinguishesNames()
+	{
+		assertNotSame(DisplayLocation.getConstant("DisplayLocationTest_Gamma"),
+			DisplayLocation.getConstant("DisplayLocationTest_Delta"));
+	}
+
+	/** valueOf returns the already-interned instance — the sibling method NOT touched in this PR. */
+	@Test
+	void valueOfReturnsInternedInstance()
+	{
+		DisplayLocation registered = DisplayLocation.getConstant("DisplayLocationTest_Epsilon");
+		assertSame(registered, DisplayLocation.valueOf("DisplayLocationTest_Epsilon"));
+	}
+
+	/** valueOf throws on an unknown name (its lookup-or-throw contract). */
+	@Test
+	void valueOfThrowsOnUnknownName()
+	{
+		assertThrows(IllegalArgumentException.class,
+			() -> DisplayLocation.valueOf("DisplayLocationTest_NeverRegistered"));
+	}
+}

code/src/test/pcgen/cdom/enumeration/RegionTest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2026 (C) Vest <Vest@users.noreply.github.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 2.1 of the License, or (at your option)
+ * any later version.
+ *
+ * This library 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 Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+package pcgen.cdom.enumeration;
+
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Pins the intern contract of {@link Region#getConstant(String)}.
+ *
+ * Fixture names are namespaced ("RegionTest_*") to avoid colliding with
+ * data-load fixtures registered by other tests sharing the JVM.
+ */
+class RegionTest
+{
+
+	/** Two calls with the same name return the same interned instance. */
+	@Test
+	void getConstantInternsByName()
+	{
+		assertSame(Region.getConstant("RegionTest_Alpha"), Region.getConstant("RegionTest_Alpha"));
+	}
+
+	/** The intern map is case-insensitive (CaseInsensitiveMap). */
+	@Test
+	void getConstantInternsCaseInsensitively()
+	{
+		assertSame(Region.getConstant("RegionTest_Beta"), Region.getConstant("regiontest_beta"));
+	}
+
+	/** Distinct names produce distinct instances. */
+	@Test
+	void getConstantDistinguishesNames()
+	{
+		assertNotSame(Region.getConstant("RegionTest_Gamma"), Region.getConstant("RegionTest_Delta"));
+	}
+}

code/src/test/pcgen/cdom/enumeration/TypeTest.java

@@ -18,6 +18,8 @@
 package pcgen.cdom.enumeration;
 
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
 
 import java.util.Collection;
 import java.util.HashSet;
@@ -28,12 +30,15 @@
 /**
  * The Class {@code TypeTest} tests that the Type
  * class is functioning correctly.
+ *
+ * Fixture names are namespaced ("TypeTest_*") so they don't collide with
+ * data-load fixtures registered by other tests sharing the JVM.
  */
 class TypeTest
 {
 	/**
 	 * Test whether type can be sorted, by adding it to a hashset.
-	 * Added to check fix on Bug with tracker nr. 2413116 
+	 * Added to check fix on Bug with tracker nr. 2413116
 	 */
 	@Test
 	void testSortable()
@@ -45,4 +50,25 @@ void testSortable()
 		}, "type can't be sorted by adding to hashset") ;
 	}
 
+	/** Two calls with the same name return the same interned instance. */
+	@Test
+	void getConstantInternsByName()
+	{
+		assertSame(Type.getConstant("TypeTest_Alpha"), Type.getConstant("TypeTest_Alpha"));
+	}
+
+	/** The intern map is case-insensitive (CaseInsensitiveMap). */
+	@Test
+	void getConstantInternsCaseInsensitively()
+	{
+		assertSame(Type.getConstant("TypeTest_Beta"), Type.getConstant("typetest_beta"));
+	}
+
+	/** Distinct names produce distinct instances. */
+	@Test
+	void getConstantDistinguishesNames()
+	{
+		assertNotSame(Type.getConstant("TypeTest_Gamma"), Type.getConstant("TypeTest_Delta"));
+	}
+
 }