net.obvj.jsonmerge

Class JsonMerger<T>

java.lang.Object

net.obvj.jsonmerge.JsonMerger<T>

Type Parameters:

T - the type that represents the actual JSON document at the specified JsonProvider

public class JsonMerger<T>
extends Object

Combines two JSON documents.

The operation is provider-agnostic and relies on a specialized JsonProvider which must be specified via constructor.

The resulting JSON document from the merge operation shall contain all exclusive objects from source documents. And in case of key collision (i.e., the same key appears in both documents), the following rules will be applied:

• For simple values, such as strings, numbers and boolean values, the value from the highest-precedence JSON document will be selected;
• If the value is a JSON object in both documents, the two objects will be merged recursively;
• If the value is a JSON array in both documents, then all distinct elements (i.e., not repeated ones) will be copied to the resulting array, unless a different JsonMergeOption is provided specifically for that array path;
• If the types are incompatible in the source JSON documents (e.g.: array in one side and simple value or complex object in the other), then a copy of the object from the highest-precedence document will be selected as fallback

Note: The first JSON document passed is always considered to have higher precedence than the second one in merge(T, T).

For advanced merge options, refer to JsonMergeOption.

Since:

1.0.0

Author:

oswaldo.bapvic.jr (Oswaldo Junior)

See Also:

JsonProvider, JsonMergeOption

Constructor Summary

Constructors

Constructor and Description
JsonMerger(Class<T> jsonObjectType) Creates a new JSON Merger for a specific JSON object type.
JsonMerger(JsonProvider<T> jsonProvider) Creates a new JSON Merger for a specific provider.

Method Summary

Modifier and Type	Method and Description
T	merge(String json1, String json2, JsonMergeOption... mergeOptions) Decodes the specified JSON strings and then combines them.
T	merge(T json1, T json2, JsonMergeOption... mergeOptions) Combines two JSON documents.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JsonMerger

public JsonMerger(JsonProvider<T> jsonProvider)

Creates a new JSON Merger for a specific provider.

Parameters:

jsonProvider - the JsonProvider to use; not null

Throws:

NullPointerException - if the specified JsonProvider is null

JsonMerger

public JsonMerger(Class<T> jsonObjectType)

Creates a new JSON Merger for a specific JSON object type.

For example:

• JSONObject.class for json-smart
• JsonObject.class for Gson
• JsonNode.class for Jackson

Parameters:

jsonObjectType - the class that represents a JSON document on a JsonProvider; not null

Throws:

NullPointerException - if the specified jsonObjectType is null

IllegalArgumentException - if no JsonProvider found for the specified jsonObjectType

Since:

1.2.0

Method Detail

merge

public T merge(T json1,
               T json2,
               JsonMergeOption... mergeOptions)

Combines two JSON documents.

Parameters:

json1 - the first JSON document; this object will have higher precedence than the other one in case of key collision

json2 - the second JSON document (lower precedence object)

mergeOptions - an array of options on how to merge the documents (optional)

Returns:

a new JSON document from the combination of json1 and json2

merge

public T merge(String json1,
               String json2,
               JsonMergeOption... mergeOptions)

Decodes the specified JSON strings and then combines them.

Parameters:

json1 - the first JSON document; this object will have higher precedence than the other one in case of key collision

json2 - the second JSON document (lower precedence object)

mergeOptions - an array of options on how to merge the documents (optional)

Returns:

a new JSON document from the combination of json1 and json2

Throws:

NullPointerException - if one of the specified strings is null

JsonParseException - if one of the the specified strings is an invalid JSON

Since:

1.2.0