add generalized error handling in http

nb-api/src/main/java/io/nosqlbench/nb/api/config/params/Element.java

@@ -1,5 +1,6 @@
 package io.nosqlbench.nb.api.config.params;
 
+import java.util.Map;
 import java.util.Optional;
 
 /**
@@ -17,4 +18,5 @@ public interface Element {
 
     <T> T getOr(String name, T defaultValue);
 
+    Map<String, Object> getMap();
 }

nb-api/src/main/java/io/nosqlbench/nb/api/config/params/ElementData.java

@@ -1,5 +1,7 @@
 package io.nosqlbench.nb.api.config.params;
 
+import java.util.Set;
+
 /**
  * A generic type-safe reader interface for parameters.
  * TODO: This should be consolidated with the design of ConfigLoader once the features of these two APIs are stabilized.
@@ -13,6 +15,8 @@ public interface ElementData {
 
     Object get(String name);
 
+    Set<String> getKeys();
+
     boolean containsKey(String name);
 
 //    default ElementData getChildElementData(String name) {

nb-api/src/main/java/io/nosqlbench/nb/api/config/params/ElementImpl.java

@@ -1,8 +1,6 @@
 package io.nosqlbench.nb.api.config.params;
 
-import java.util.Arrays;
-import java.util.List;
-import java.util.Optional;
+import java.util.*;
 
 public class ElementImpl implements Element {
 
@@ -50,5 +48,18 @@ public class ElementImpl implements Element {
         return get(name, cls).orElse(defaultValue);
     }
 
+    @Override
+    public Map<String, Object> getMap() {
+        Set<String> keys = this.data.getKeys();
+        Map<String, Object> map = new LinkedHashMap<>();
+
+        for (String key : keys) {
+            Object value = this.data.get(key);
+            map.put(key, value);
+        }
+
+        return map;
+    }
+
 
 }

nb-api/src/main/java/io/nosqlbench/nb/api/config/params/JsonBackedConfigElement.java

@@ -5,6 +5,8 @@ import com.google.gson.GsonBuilder;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 
+import java.util.Set;
+
 public class JsonBackedConfigElement implements ElementData {
 
     private final Gson gson = new GsonBuilder().setPrettyPrinting().create();
@@ -20,6 +22,11 @@ public class JsonBackedConfigElement implements ElementData {
         return jsonObject.get(name);
     }
 
+    @Override
+    public Set<String> getKeys() {
+        return jsonObject.keySet();
+    }
+
     @Override
     public boolean containsKey(String name) {
         return jsonObject.keySet().contains(name);

nb-api/src/main/java/io/nosqlbench/nb/api/config/params/MapBackedElement.java

@@ -1,6 +1,7 @@
 package io.nosqlbench.nb.api.config.params;
 
 import java.util.Map;
+import java.util.Set;
 
 public class MapBackedElement implements ElementData {
 
@@ -15,6 +16,11 @@ public class MapBackedElement implements ElementData {
         return map.get(name);
     }
 
+    @Override
+    public Set<String> getKeys() {
+        return map.keySet();
+    }
+
     @Override
     public boolean containsKey(String name) {
         return map.containsKey(name);