add may be empty array

taowen · taowen · commit ba367c99fbb6 · 2017-01-10T09:46:04.000+08:00
diff --git a/src/main/java/com/jsoniter/spi/Decoder.java b/src/main/java/com/jsoniter/spi/Decoder.java
@@ -2,6 +2,7 @@
 
 import com.jsoniter.CodegenAccess;
 import com.jsoniter.JsonIterator;
+import com.jsoniter.ValueType;
 
 import java.io.IOException;
 
@@ -244,4 +245,21 @@ public double decodeDouble(JsonIterator iter) throws IOException {
             return val;
         }
     }
+
+    class MaybeEmptyArrayDecoder implements Decoder {
+
+        @Override
+        public Object decode(JsonIterator iter) throws IOException {
+            if (iter.whatIsNext() == ValueType.ARRAY) {
+                if (iter.readArray()) {
+                    throw iter.reportError("MaybeEmptyArrayDecoder", "this field is object. if input is array, it can only be empty");
+                } else {
+                    // empty array parsed as null
+                    return null;
+                }
+            } else {
+                return iter.read(iter);
+            }
+        }
+    }
 }
diff --git a/src/test/java/com/jsoniter/TestObject.java b/src/test/java/com/jsoniter/TestObject.java
@@ -1,6 +1,9 @@
 package com.jsoniter;
 
+import com.jsoniter.annotation.JsonProperty;
+import com.jsoniter.annotation.JsoniterAnnotationSupport;
 import com.jsoniter.any.Any;
+import com.jsoniter.spi.Decoder;
 import com.jsoniter.spi.EmptyExtension;
 import com.jsoniter.spi.JsoniterSpi;
 import junit.framework.TestCase;
@@ -163,4 +166,15 @@ public void test_enum() throws IOException {
         obj = JsonIterator.deserialize("{\"field1\":\"WOW\"}", TestObject5.class);
         assertEquals(TestObject5.MyEnum.WOW, obj.field1);
     }
+
+    public static class TestObject6 {
+        @JsonProperty(decoder = Decoder.MaybeEmptyArrayDecoder.class)
+        public Map<String, Object> field1;
+    }
+
+    public void test_maybe_empty_array_field() {
+        JsoniterAnnotationSupport.enable();
+        TestObject6 obj = JsonIterator.deserialize("{\"field1\":[]}", TestObject6.class);
+        assertNull(obj.field1);
+    }
 }
