Added back function of HeadersCodec.contentType

Author: artem-v

services-api/src/main/java/io/scalecube/services/transport/api/HeadersCodec.java

@@ -1,14 +1,40 @@
 package io.scalecube.services.transport.api;
 
+import io.scalecube.utils.ServiceLoaderUtil;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 public interface HeadersCodec {
 
   HeadersCodec DEFAULT_INSTANCE = new JdkCodec();
 
+  Map<String, HeadersCodec> INSTANCES = new ConcurrentHashMap<>();
+
+  static HeadersCodec getInstance(String contentType) {
+    return INSTANCES.computeIfAbsent(contentType, HeadersCodec::loadInstance);
+  }
+
+  /**
+   * Returns {@link HeadersCodec} by given {@code contentType}.
+   *
+   * @param contentType contentType (required)
+   * @return {@link HeadersCodec} by given {@code contentType} (or throws IllegalArgumentException
+   *     is thrown if not exist)
+   */
+  static HeadersCodec loadInstance(String contentType) {
+    return ServiceLoaderUtil.findFirst(
+            HeadersCodec.class, codec -> codec.contentType().equalsIgnoreCase(contentType))
+        .orElseThrow(
+            () ->
+                new IllegalArgumentException(
+                    "HeadersCodec for '" + contentType + "' not configured"));
+  }
+
+  String contentType();
+
   void encode(OutputStream stream, Map<String, String> headers) throws IOException;
 
   Map<String, String> decode(InputStream stream) throws IOException;