Correct hashCode calculation.

common/src/main/java/com/msd/gin/halyard/common/IdentifiableValue.java

@@ -143,7 +143,7 @@ private IdSer createIdSer(ValueIdentifier id, boolean makeId, ByteArray ser, @No
 			if (serBytes == null) {
 				serBytes = ser.copyBytes();
 			}
-			id = rdfFactory.id(this, serBytes);
+			id = rdfFactory.getId(serBytes);
 		}
 		return new IdSer(id, ser, rdfFactory);
 	}

common/src/main/java/com/msd/gin/halyard/common/RDFFactory.java

@@ -142,9 +142,7 @@ private RDFFactory(HalyardTableConfiguration halyardConfig) {
 			idSize = confIdSize;
 		}
 		int typeIndex = lessThan(lessThanOrEqual(greaterThanOrEqual(halyardConfig.getInt(TableConfig.ID_TYPE_INDEX), 0), Short.BYTES), idSize);
-		if (confIdJavaHash) {
-			greaterThanOrEqual(idSize, typeIndex + 1 + Integer.BYTES); // salt & typing bytes + 4 bytes for the Java int hash code
-		}
+		greaterThanOrEqual(idSize, ValueIdentifier.Format.minSize(typeIndex, confIdJavaHash));
 		ValueIdentifier.TypeNibble typeNibble = halyardConfig.getBoolean(TableConfig.ID_TYPE_NIBBLE) ? ValueIdentifier.TypeNibble.LITTLE_NIBBLE : ValueIdentifier.TypeNibble.BIG_NIBBLE;
 		idFormat = new ValueIdentifier.Format(confIdAlgo, idSize, typeIndex, typeNibble, confIdJavaHash);
 		LOGGER.info("Identifier format: {}", idFormat);
@@ -363,7 +361,7 @@ public ValueIdentifier id(Value v) {
 				id = idv.getId(this);
 			} else {
 				byte[] ser = valueWriter.toBytes(v);
-				id = id(v, ser);
+				id = getId(ser);
 			}
 		}
 		return id;
@@ -376,8 +374,8 @@ public ValueIdentifier id(byte[] idBytes) {
 		return new ValueIdentifier(idBytes);
 	}
 
-	ValueIdentifier id(Value v, byte[] ser) {
-		return idFormat.id(v, ser);
+	ValueIdentifier getId(byte[] ser) {
+		return idFormat.id(ser, valueReader);
 	}
 
 	public ValueIdentifier idFromString(String s) {

common/src/main/java/com/msd/gin/halyard/common/RDFValue.java

@@ -46,7 +46,7 @@ protected final ValueIdentifier calculateId() {
 		if (val instanceof IdentifiableValue) {
 			return ((IdentifiableValue) val).getId(rdfFactory);
 		} else {
-			return rdfFactory.id(val, getSerializedForm().copyBytes());
+			return rdfFactory.getId(getSerializedForm().copyBytes());
 		}
 	}
 

common/src/main/java/com/msd/gin/halyard/common/ValueIdentifier.java

@@ -16,6 +16,7 @@
 import org.eclipse.rdf4j.model.IRI;
 import org.eclipse.rdf4j.model.Literal;
 import org.eclipse.rdf4j.model.Value;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
 
 /**
  * Immutable wrapper around a byte array identifier.
@@ -78,6 +79,11 @@ private TypeNibble(byte literalTypeBits, byte tripleTypeBits, byte iriTypeBits,
 	static final class Format implements Serializable {
 		private static final long serialVersionUID = -7777885367792871664L;
 
+		static int minSize(int typeIndex, boolean hasJavaHash) {
+			// salt & typing bytes + 4 bytes for the Java int hash code
+			return typeIndex + 1 + (hasJavaHash ? Integer.BYTES : 0);
+		}
+
 		final String algorithm;
 		final int size;
 		final int typeIndex;
@@ -94,6 +100,9 @@ static final class Format implements Serializable {
 		 * @param hasJavaHash indicates whether to include the Java hash as part of the ID.
 		 */
 		Format(String algorithm, int size, int typeIndex, TypeNibble typeNibble, boolean hasJavaHash) {
+			if (hasJavaHash && size < minSize(typeIndex, hasJavaHash)) {
+				throw new IllegalArgumentException("Size is too small");
+			}
 			this.size = size;
 			this.algorithm = algorithm;
 			this.typeIndex = typeIndex;
@@ -135,12 +144,13 @@ int getSaltSize() {
 		/**
 		 * Thread-safe.
 		 */
-		ValueIdentifier id(Value v, byte[] ser) {
+		ValueIdentifier id(byte[] ser, ValueIO.Reader reader) {
 			byte[] hash = new byte[size];
 			if (hashFuncProvider != null) {
 				byte[] algoHash = hashFuncProvider.get().apply(ser);
 				System.arraycopy(algoHash, 0, hash, 0, algoHash.length);
 			}
+			Value v = reader.readValue(ByteBuffer.wrap(ser), SimpleValueFactory.getInstance());
 			if (hasJavaHash) {
 				int jhash = v.hashCode();
 				int i = size - 1;
@@ -336,11 +346,16 @@ public boolean equals(Object o) {
 	 */
 	@Override
 	public int hashCode() {
-		int h = 0;
-		for (int i = Math.min(idBytes.length - Integer.BYTES, 0); i < idBytes.length; i++) {
-			h = (h << 8) | (idBytes[i] & 0xFF);
+		if (idBytes.length >= Integer.BYTES) {
+			int i = idBytes.length - Integer.BYTES;
+			return (idBytes[i++] & 0xFF) << 24 | (idBytes[i++] & 0xFF) << 16 | (idBytes[i++] & 0xFF) << 8 | (idBytes[i++] & 0xFF);
+		} else {
+			int h = 0;
+			for (int i = Math.max(idBytes.length - Integer.BYTES, 0); i < idBytes.length; i++) {
+				h = (h << 8) | (idBytes[i] & 0xFF);
+			}
+			return h;
 		}
-		return h;
 	}
 
 	@Override

common/src/test/java/com/msd/gin/halyard/common/ValueIdentifierTest.java

@@ -0,0 +1,37 @@
+package com.msd.gin.halyard.common;
+
+import com.msd.gin.halyard.common.ValueIdentifier.TypeNibble;
+
+import org.eclipse.rdf4j.model.Literal;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ValueIdentifierTest {
+	@Test
+	public void testIDTooShort() {
+		assertThrows(IllegalArgumentException.class, () ->
+			new ValueIdentifier.Format("Murmur3-128", 5, 1, TypeNibble.BIG_NIBBLE, true)
+		);
+	}
+
+	@Test
+	public void testHashCode_shortID() {
+		ValueFactory vf = SimpleValueFactory.getInstance();
+		ValueIdentifier.Format f = new ValueIdentifier.Format("Murmur3-128", 3, 1, TypeNibble.BIG_NIBBLE, false);
+		Literal l = vf.createLiteral("foobar");
+		ValueIdentifier id = f.id(ValueIO.getDefaultWriter().toBytes(l), ValueIO.getDefaultReader());
+		assertEquals(9124272, id.hashCode());
+	}
+
+	@Test
+	public void testHashCode_longID() {
+		ValueFactory vf = SimpleValueFactory.getInstance();
+		ValueIdentifier.Format f = new ValueIdentifier.Format("Murmur3-128", 6, 1, TypeNibble.BIG_NIBBLE, true);
+		Literal l = vf.createLiteral("foobar");
+		ValueIdentifier id = f.id(ValueIO.getDefaultWriter().toBytes(l), ValueIO.getDefaultReader());
+		assertEquals(l.hashCode(), id.hashCode());
+	}
+}