Extract session identifier serializer location from SessionKeyExterna…

…lizer.

clustering/web/infinispan/src/main/java/org/wildfly/clustering/web/infinispan/SessionIdentifierSerializer.java

@@ -0,0 +1,57 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ * Copyright 2018, Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags. See the copyright.txt file in the
+ * distribution for a full listing of individual contributors.
+ *
+ * This 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 software 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 software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+
+package org.wildfly.clustering.web.infinispan;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.ServiceLoader;
+
+import org.wildfly.clustering.marshalling.spi.Serializer;
+import org.wildfly.clustering.web.IdentifierSerializerProvider;
+
+/**
+ * @author Paul Ferraro
+ */
+public enum SessionIdentifierSerializer implements Serializer<String> {
+    INSTANCE;
+
+    private final Serializer<String> serializer = load(IdentifierSerializerProvider.class.getClassLoader());
+
+    private static final Serializer<String> load(ClassLoader loader) {
+        for (IdentifierSerializerProvider provider : ServiceLoader.load(IdentifierSerializerProvider.class, loader)) {
+            return provider.getSerializer();
+        }
+        throw new IllegalStateException();
+    }
+
+    @Override
+    public void write(DataOutput output, String value) throws IOException {
+        this.serializer.write(output, value);
+    }
+
+    @Override
+    public String read(DataInput input) throws IOException {
+        return this.serializer.read(input);
+    }
+}

clustering/web/infinispan/src/main/java/org/wildfly/clustering/web/infinispan/SessionKeyExternalizer.java

@@ -25,29 +25,17 @@
 import java.io.IOException;
 import java.io.ObjectInput;
 import java.io.ObjectOutput;
-import java.util.ServiceLoader;
 import java.util.function.Function;
 
 import org.wildfly.clustering.infinispan.spi.distribution.Key;
 import org.wildfly.clustering.marshalling.Externalizer;
-import org.wildfly.clustering.marshalling.spi.Serializer;
-import org.wildfly.clustering.web.IdentifierSerializerProvider;
 
 /**
  * Base externalizer for cache keys containing session identifiers.
  * @author Paul Ferraro
  */
 public class SessionKeyExternalizer<K extends Key<String>> implements Externalizer<K> {
 
-    static final Serializer<String> SESSION_ID_SERIALIZER = loadIdentifierSerializer(IdentifierSerializerProvider.class.getClassLoader());
-
-    private static Serializer<String> loadIdentifierSerializer(ClassLoader loader) {
-        for (IdentifierSerializerProvider provider : ServiceLoader.load(IdentifierSerializerProvider.class, loader)) {
-            return provider.getSerializer();
-        }
-        throw new IllegalStateException();
-    }
-
     private final Class<K> targetClass;
     private final Function<String, K> resolver;
 
@@ -58,12 +46,12 @@ protected SessionKeyExternalizer(Class<K> targetClass, Function<String, K> resol
 
     @Override
     public void writeObject(ObjectOutput output, K key) throws IOException {
-        SESSION_ID_SERIALIZER.write(output, key.getValue());
+        SessionIdentifierSerializer.INSTANCE.write(output, key.getValue());
     }
 
     @Override
     public K readObject(ObjectInput input) throws IOException {
-        return this.resolver.apply(SESSION_ID_SERIALIZER.read(input));
+        return this.resolver.apply(SessionIdentifierSerializer.INSTANCE.read(input));
     }
 
     @Override