#151 BytesMarshallable and interface value classes not supported.

src/main/java/net/openhft/chronicle/map/ChronicleMapBuilder.java

@@ -21,6 +21,7 @@ import net.openhft.chronicle.algo.MemoryUnit;
 import net.openhft.chronicle.algo.hashing.LongHashFunction;
 import net.openhft.chronicle.bytes.Byteable;
 import net.openhft.chronicle.bytes.Bytes;
+import net.openhft.chronicle.bytes.BytesMarshallable;
 import net.openhft.chronicle.core.Jvm;
 import net.openhft.chronicle.core.OS;
 import net.openhft.chronicle.hash.ChronicleHashBuilder;
@@ -43,10 +44,7 @@ import org.jetbrains.annotations.NotNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.File;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.RandomAccessFile;
+import java.io.*;
 import java.lang.reflect.InvocationTargetException;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
@@ -653,6 +651,14 @@ public final class ChronicleMapBuilder<K, V> implements
      * @see #actualChunkSize(int)
      */
     public ChronicleMapBuilder<K, V> averageValue(V averageValue) {
+        Class<?> valueClass = averageValue.getClass();
+        if (BytesMarshallable.class.isAssignableFrom(valueClass) &&
+                valueBuilder.tClass.isInterface()) {
+            if (Serializable.class.isAssignableFrom(valueClass))
+                LOG.warn("BytesMarshallable " + valueClass + " will be serialized as Serializable as the value class is an interface");
+            else
+                throw new IllegalArgumentException("Using BytesMarshallable and an interface value type not supported");
+        }
         Objects.requireNonNull(averageValue);
         checkSizeIsStaticallyKnown(valueBuilder, "Value");
         this.averageValue = averageValue;

src/test/java/net/openhft/chronicle/map/ChronicleMapTest.java

@@ -19,6 +19,7 @@ package net.openhft.chronicle.map;
 
 import com.google.common.collect.HashBiMap;
 import com.google.common.primitives.Ints;
+import net.openhft.chronicle.bytes.BytesMarshallable;
 import net.openhft.chronicle.bytes.BytesStore;
 import net.openhft.chronicle.core.values.IntValue;
 import net.openhft.chronicle.core.values.LongValue;
@@ -1863,6 +1864,25 @@ public class ChronicleMapTest {
         tmpFile.delete();
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testBytesMarshallableMustBeConcreteValueType() {
+        try (ChronicleMap<CharSequence, BMSUper> map = ChronicleMapBuilder
+                .of(CharSequence.class, BMSUper.class)
+                .entries(1)
+                .averageKey("hello")
+                .averageValue(new BMClass())
+                .create()) {
+            map.put("hi", new BMClass());
+        }
+    }
+
+    interface BMSUper {
+
+    }
+
+    static class BMClass implements BytesMarshallable, BMSUper {
+
+    }
     private static final class IncrementRunnable implements Runnable {
 
         private final ChronicleMap<CharSequence, LongValue> map;