You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@johnzon.apache.org by "Kaloyan Spiridonov (JIRA)" <ji...@apache.org> on 2017/06/06 09:10:19 UTC

[jira] [Reopened] (JOHNZON-124) JsonArrayImpl should not override equals method

     [ https://issues.apache.org/jira/browse/JOHNZON-124?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kaloyan Spiridonov reopened JOHNZON-124:
----------------------------------------

With the current implementation list equals implementation is broken 
{code}
	public static void main(String[] args) {
		JsonReader reader = Json.createReader(new StringReader("[true]"));
	    JsonArray jsonArray = reader.readArray();
    	
    	List<JsonValue> list = new ArrayList<JsonValue>();
     	list.add(JsonValue.TRUE);
     	
    	System.out.println(jsonArray.equals(list));
    	System.out.println(list.equals(jsonArray));
	}
{code}
Expected output:
{code}
true
true
{code}

Actual output:
{code}
false
true
{code}

According to the equals contract it must be transitive.
{quote}
 In other words, two lists are defined to be equal if they contain the same elements in the same order. This definition ensures that the equals method works properly across different implementations of the List interface.
{quote}

In other words, the equality does not depend on the type of the list.

> JsonArrayImpl should not override equals method
> -----------------------------------------------
>
>                 Key: JOHNZON-124
>                 URL: https://issues.apache.org/jira/browse/JOHNZON-124
>             Project: Johnzon
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.0.0
>            Reporter: Kaloyan Spiridonov
>            Assignee: Romain Manni-Bucau
>             Fix For: 1.1.2
>
>
> According to javadoc the equals method of JsonArray should be inherited from List.  The javadoc of java.util.List.equals(Object o) says:
> {quote}
> Compares the specified object with this list for equality. Returns true if and only if the specified object is also a list, both lists have the same size, and all corresponding pairs of elements in the two lists are equal. (Two elements e1 and e2 are equal if (e1==null ? e2==null : e1.equals(e2)).) In other words, two lists are defined to be equal if they contain the same elements in the same order. This definition ensures that the equals method works properly across different implementations of the List interface.
> {quote}
> The following code:
> {code}
> JsonReader reader = Json.createReader(new StringReader("[true]"));
> 	    JsonArray jsonArray = reader.readArray();
>     	List<JsonValue> actList = jsonArray;
>     	
>     	List<JsonValue> list = new ArrayList<JsonValue>();
>      	list.add(JsonValue.TRUE);
>     	System.out.println(actList.equals(list));
> {code}
> should return true instead of false.
> One fix will be just to remove the equals method from JsonArrayImpl and then the AbstractList<E>.equals(Object paramObject) will be used.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)