Add a check on the duplicated event names hyperledger-web3j#1781

Author: mattiamonari

codegen/src/main/java/org/web3j/codegen/SolidityFunctionWrapper.java

@@ -423,6 +423,7 @@ private List<MethodSpec> buildFunctionDefinitions(
             throws ClassNotFoundException {
 
         Set<String> duplicateFunctionNames = getDuplicateFunctionNames(functionDefinitions);
+        changeEventsName(functionDefinitions);
         List<MethodSpec> methodSpecs = new ArrayList<>();
         for (AbiDefinition functionDefinition : functionDefinitions) {
             if (functionDefinition.getType().equals(TYPE_FUNCTION)) {
@@ -436,6 +437,25 @@ private List<MethodSpec> buildFunctionDefinitions(
         return methodSpecs;
     }
 
+    private void changeEventsName(List<AbiDefinition> functionDefinitions) {
+
+        Map<String, Integer> countMap = new HashMap<>();
+
+        for (AbiDefinition functionDefinition : functionDefinitions) {
+            if (TYPE_EVENT.equals(functionDefinition.getType())
+                    && functionDefinition.getName() != null) {
+                String s = functionDefinition.getName();
+                if (countMap.containsKey(s)) {
+                    int count = countMap.get(s);
+                    functionDefinition.setName(s + count);
+                    countMap.put(s, count + 1);
+                } else {
+                    countMap.put(s, 1);
+                }
+            }
+        }
+    }
+
     private List<TypeSpec> buildStructTypes(final List<AbiDefinition> functionDefinitions)
             throws ClassNotFoundException {
         final List<AbiDefinition.NamedType> orderedKeys = extractStructs(functionDefinitions);
@@ -723,6 +743,7 @@ Iterable<FieldSpec> buildFuncNameConstants(List<AbiDefinition> functionDefinitio
         Set<String> fieldNames = new HashSet<>();
         fieldNames.add(Contract.FUNC_DEPLOY);
         Set<String> duplicateFunctionNames = getDuplicateFunctionNames(functionDefinitions);
+        changeEventsName(functionDefinitions);
         if (!duplicateFunctionNames.isEmpty()) {
             System.out.println(
                     "\nWarning: Duplicate field(s) found: "