Adding "UNWRAP_SINGLE_VALUE_ARRAYS" DeserializationFeature

Fixes issue #381. Added new feature that determines whether it is acceptable to coerce a single value array (in JSON) to the corresponding value type.
FasterXML · Jan 8, 2014 · 0e37a39 · 0e37a39
1 parent ad9a43f
commit 0e37a39
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Showing 9 changed files with 561 additions and 15 deletions.
diff --git a/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java b/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java
@@ -203,6 +203,15 @@ public enum DeserializationFeature implements ConfigFeature
      * Feature is disabled by default.
      */
     ACCEPT_SINGLE_VALUE_AS_ARRAY(false),
+
+    /**
+     * Feature that determines whether it is acceptable to coerce single value array (in JSON)
+     * values to the corresponding value type.  This is basically the opposite of the {@link #ACCEPT_SINGLE_VALUE_AS_ARRAY}
+     * feature.  If more than one value is found in the array, a JsonMappingException is thrown.
+     * <p>
+     * Feature is disabled by default
+     */
+    UNWRAP_SINGLE_VALUE_ARRAYS(false),
 
     /**
      * Feature to allow "unwrapping" root-level JSON value, to match setting of

diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/std/DateDeserializers.java b/src/main/java/com/fasterxml/jackson/databind/deser/std/DateDeserializers.java
@@ -13,6 +13,7 @@
 
 import com.fasterxml.jackson.databind.BeanProperty;
 import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JsonDeserializer;
 import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
@@ -143,19 +144,33 @@ public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanPro
         protected java.util.Date _parseDate(JsonParser jp, DeserializationContext ctxt)
             throws IOException, JsonProcessingException
         {
-            if (_customFormat != null && jp.getCurrentToken() == JsonToken.VALUE_STRING) {
-                String str = jp.getText().trim();
-                if (str.length() == 0) {
-                    return (Date) getEmptyValue();
-                }
-                synchronized (_customFormat) {
-                    try {
-                        return _customFormat.parse(str);
-                    } catch (ParseException e) {
-                        throw new IllegalArgumentException("Failed to parse Date value '"+str
-                                +"' (format: \""+_formatString+"\"): "+e.getMessage());
+            if (_customFormat != null) {
+                JsonToken t = jp.getCurrentToken();
+                if (t == JsonToken.VALUE_STRING) {
+                    String str = jp.getText().trim();
+                    if (str.length() == 0) {
+                        return (Date) getEmptyValue();
+                    }
+                    synchronized (_customFormat) {
+                        try {
+                            return _customFormat.parse(str);
+                        } catch (ParseException e) {
+                            throw new IllegalArgumentException("Failed to parse Date value '"+str
+                                    +"' (format: \""+_formatString+"\"): "+e.getMessage());
+                        }
                     }
                 }
+                // Issue#381
+                if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+                    jp.nextToken();
+                    final Date parsed = _parseDate(jp, ctxt);
+                    t = jp.nextToken();
+                    if (t != JsonToken.END_ARRAY) {
+                        throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY, 
+                                "Attempted to unwrap single value array for single 'java.util.Date' value but there was more than a single value in the array");
+                    }            
+                    return parsed;            
+                }
             }
             return super._parseDate(jp, ctxt);
         }

diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/std/EnumDeserializer.java b/src/main/java/com/fasterxml/jackson/databind/deser/std/EnumDeserializer.java
@@ -111,6 +111,19 @@ public Enum<?> deserialize(JsonParser jp, DeserializationContext ctxt)
             }
             return result;
         }
+
+        // Issue#381
+        if (curr == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+            jp.nextToken();
+            final Enum<?> parsed = deserialize(jp, ctxt);
+            curr = jp.nextToken();
+            if (curr != JsonToken.END_ARRAY) {
+                throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY,
+                        "Attempted to unwrap single value array for single '" + _resolver.getEnumClass().getName() + "' value but there was more than a single value in the array");
+            }
+            return parsed;
+        }
+
         throw ctxt.mappingException(_resolver.getEnumClass());
     }
 

diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/std/FromStringDeserializer.java b/src/main/java/com/fasterxml/jackson/databind/deser/std/FromStringDeserializer.java
@@ -13,6 +13,7 @@
 
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.exc.InvalidFormatException;
 import com.fasterxml.jackson.databind.util.ClassUtil;
@@ -98,6 +99,16 @@ public static Std findDeserializer(Class<?> rawType)
     @Override
     public T deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException
     {
+        // Issue#381
+        if (jp.getCurrentToken() == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+            jp.nextToken();
+            final T value = deserialize(jp, ctxt);
+            if (jp.nextToken() != JsonToken.END_ARRAY) {
+                throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY, 
+                                "Attempted to unwrap single value array for single '" + _valueClass.getName() + "' value but there was more than a single value in the array");
+            }
+            return value;
+        }
         // 22-Sep-2012, tatu: For 2.1, use this new method, may force coercion:
         String text = jp.getValueAsString();
         if (text != null) { // has String representation

diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/std/NumberDeserializers.java b/src/main/java/com/fasterxml/jackson/databind/deser/std/NumberDeserializers.java
@@ -238,10 +238,9 @@ public Character deserialize(JsonParser jp, DeserializationContext ctxt)
             throws IOException, JsonProcessingException
         {
             JsonToken t = jp.getCurrentToken();
-            int value;
-
+
             if (t == JsonToken.VALUE_NUMBER_INT) { // ok iff ascii value
-                value = jp.getIntValue();
+                int value = jp.getIntValue();
                 if (value >= 0 && value <= 0xFFFF) {
                     return Character.valueOf((char) value);
                 }
@@ -254,7 +253,21 @@ public Character deserialize(JsonParser jp, DeserializationContext ctxt)
                 // actually, empty should become null?
                 if (text.length() == 0) {
                     return (Character) getEmptyValue();
+                }               
+            } else if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+                //Issue#381
+                jp.nextToken();
+                final Character value = deserialize(jp, ctxt);
+                if (jp.nextToken() != JsonToken.END_ARRAY) {
+                    throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY, 
+                            "Attempted to unwrap single value array for single '" + _valueClass.getName() + "' value but there was more than a single value in the array"
+                            );
                 }
+                return value;
+            } else if (t == JsonToken.VALUE_NULL && !_valueClass.isPrimitive()) {
+                //Issue#unreported
+                //  This handles the case where the value required is the Character wrapper class and the token is the null token
+                return getEmptyValue();
             }
             throw ctxt.mappingException(_valueClass, t);
         }
@@ -436,6 +449,17 @@ public Number deserialize(JsonParser jp, DeserializationContext ctxt)
                     throw ctxt.weirdStringException(text, _valueClass, "not a valid number");
                 }
             }
+
+            if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+                jp.nextToken();
+                final Number value = deserialize(jp, ctxt);
+                if (jp.nextToken() != JsonToken.END_ARRAY) {
+                    throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY, 
+                            "Attempted to unwrap single value array for single '" + _valueClass.getName() + "' value but there was more than a single value in the array"
+                            );
+                }
+                return value;
+            }
             // Otherwise, no can do:
             throw ctxt.mappingException(_valueClass, t);
         }
@@ -502,10 +526,19 @@ public BigInteger deserialize(JsonParser jp, DeserializationContext ctxt)
                  * Could do by calling BigDecimal.toBigIntegerExact()
                  */
                 return jp.getDecimalValue().toBigInteger();
+            } else if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+                jp.nextToken();
+                final BigInteger value = deserialize(jp, ctxt);
+                if (jp.nextToken() != JsonToken.END_ARRAY) {
+                    throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY,
+                        "Attempted to unwrap single value array for single 'BigInteger' value but there was more than a single value in the array"
+                    );
+                }
+                return value;
             } else if (t != JsonToken.VALUE_STRING) { // let's do implicit re-parse
                 // String is ok too, can easily convert; otherwise, no can do:
                 throw ctxt.mappingException(_valueClass, t);
-            }
+            }            
             text = jp.getText().trim();
             if (text.length() == 0) {
                 return null;
@@ -547,6 +580,17 @@ public BigDecimal deserialize(JsonParser jp, DeserializationContext ctxt)
                     throw ctxt.weirdStringException(text, _valueClass, "not a valid representation");
                 }
             }
+
+            if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+                jp.nextToken();
+                final BigDecimal value = deserialize(jp, ctxt);
+                if (jp.nextToken() != JsonToken.END_ARRAY) {
+                    throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY,
+                        "Attempted to unwrap single value array for single 'BigDecimal' value but there was more than a single value in the array"
+                    );
+                }
+                return value;
+            }
             // Otherwise, no can do:
             throw ctxt.mappingException(_valueClass, t);
         }

diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/std/StackTraceElementDeserializer.java b/src/main/java/com/fasterxml/jackson/databind/deser/std/StackTraceElementDeserializer.java
@@ -6,6 +6,7 @@
 import com.fasterxml.jackson.core.JsonToken;
 
 import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JsonMappingException;
 
 public class StackTraceElementDeserializer
@@ -45,7 +46,17 @@ public StackTraceElement deserialize(JsonParser jp, DeserializationContext ctxt)
                 }
             }
             return new StackTraceElement(className, methodName, fileName, lineNumber);
+        } else if (t == JsonToken.START_ARRAY && ctxt.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)) {
+            jp.nextToken();
+            final StackTraceElement value = deserialize(jp, ctxt);
+            if (jp.nextToken() != JsonToken.END_ARRAY) {
+                throw ctxt.wrongTokenException(jp, JsonToken.END_ARRAY,
+                        "Attempted to unwrap single value array for single 'java.lang.StackTraceElement' value but there was more than a single value in the array"
+                    );
+            }
+            return value;
         }
+
         throw ctxt.mappingException(_valueClass, t);
     }
 }