fixes #54 support for draft V6, V7 and V2019-09

[stevehu]

I have spent several hours today to refactor the library so that we can support multiple specification versions easily for both developers and end-users. @jawaff and I have discussed the design for several days in the #206 and we finally decide to implement it this way.

I also added a document in the doc folder named specversion.md for both users and developers.

[jawaff]

The changes look really good for the most part. The only other thing I can think to comment on is the fact that the draft 4 SpecVersion is hard coded into a lot of the tests. Maybe you could use Junit's Parameterized test runner. (I use TestNG more than Junit, so sorry if I'm not sure how to use this correctly.) It looks like the Parameterized test runner would allow the tests to be executed for each SpecVersion. That's just a suggestion in order to improve the tests, but it might not be necessary.

[stevehu]

I haven't thought about the test cases in detail yet. Hardcoded V4 is to ensure that all the changes are backward compatible so that it won't impact the current users. If there is a way that we can run the test against all spec factory, it will be great. I am not familiar with TestNG, would you please try something? Thanks.

[codecov-io]

Codecov Report

Merging #213 into master will increase coverage by 0.66%.
The diff coverage is 79.12%.

@@             Coverage Diff              @@
##             master     #213      +/-   ##
============================================
+ Coverage     70.12%   70.79%   +0.66%     
- Complexity      520      567      +47     
============================================
  Files            62       68       +6     
  Lines          2032     2236     +204     
  Branches        441      482      +41     
============================================
+ Hits           1425     1583     +158     
- Misses          419      457      +38     
- Partials        188      196       +8

Impacted Files	Coverage Δ	Complexity Δ
.../main/java/com/networknt/schema/TrueValidator.java	100% <100%> (ø)	3 <3> (?)
src/main/java/com/networknt/schema/JsonSchema.java	87.67% <100%> (+1.51%)	28 <0> (+2)	⬆️
.../main/java/com/networknt/schema/EnumValidator.java	67.44% <100%> (+2.44%)	10 <0> (+2)	⬆️
...main/java/com/networknt/schema/FalseValidator.java	100% <100%> (ø)	3 <3> (?)
...main/java/com/networknt/schema/ConstValidator.java	100% <100%> (ø)	7 <7> (?)
...rc/main/java/com/networknt/schema/SpecVersion.java	100% <100%> (ø)	6 <6> (?)
...a/com/networknt/schema/SchemaValidatorsConfig.java	87.5% <100%> (ø)	8 <0> (ø)	⬇️
...om/networknt/schema/ExclusiveMaximumValidator.java	40.47% <40.47%> (ø)	5 <5> (?)
...om/networknt/schema/ExclusiveMinimumValidator.java	40.47% <40.47%> (ø)	6 <6> (?)
...n/java/com/networknt/schema/JsonSchemaFactory.java	74.21% <92.3%> (+2.47%)	24 <5> (+4)	⬆️
... and 12 more

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[jawaff]

I don't know if I should commit to your pull request. I was always taught not to commit to other people's branches at my workplace. I'm just going to show an example of what I'm talking about and I can add a commit if you really want me to.

// This tells Junit that this test class should be parameterized.
@RunWith(Parameterized.class)
public class UriMappingTest {
    // This specifies the static method that supplies the parameters for each execution.
    @Parameterized.Parameters
    public static Collection<?> parameters() {
      return Arrays.asList(new Object[][] {
         { "draft4", JsonMetaSchema.getV4() },
         { "draft6", JsonMetaSchema.getV6() },
         { "draft7", JsonMetaSchema.getV7() },
         { "draft201909", JsonMetaSchema.getV201909() }
      });
    }

    private final ObjectMapper mapper = new ObjectMapper();
    private final ClasspathURLFactory classpathURLFactory = new ClasspathURLFactory();
    private final URLFactory urlFactory = new URLFactory();

    private final String resourcePrefix;
    private final JsonMetaSchema metaSchema;
    // This constructor is where the parameters are injected by Junit.
    public UriMappingTest(String resourcePrefix, JsonMetaSchema metaSchema) {
        super()
        this.resourcePrefix = resourcePrefix;
        this.metaSchema = metaSchema;
    }

   // This test will run 4 times. Each time will be with different this.resourcePrefix and this.metaSchema values.
    // One assumption is that there is a uri-mapping.json file in each one of the draft resource directories. It's possible that the same uri-mapping.json file could be reused for each draft version to ensure backwards compatibility, but maybe the uri-mapping.json files need to be different depending on the draft version.
   @Test
    public void testBuilderUriMappingUri() throws IOException {
        URL mappings = ClasspathURLFactory.convert(
                this.classpathURLFactory.create(String.format("resource:%s/uri_mapping/uri-mapping.json", this.resourcePrefix)));
        Builder builder = JsonSchemaFactory.builder()
                .defaultMetaSchemaURI(this.metaSchema.getUri())
                .addMetaSchema(this.metaSchema)
                .addUriMappings(getUriMappingsFromUrl(mappings));
        JsonSchemaFactory instance = builder.build();
        JsonSchema schema = instance.getSchema(this.urlFactory.create(
                String.format("https://raw.githubusercontent.com/networknt/json-schema-validator/master/src/test/resources/%s/uri_mapping/uri-mapping.schema.json", this.resourcePrefix)));
        assertEquals(0, schema.validate(mapper.readTree(mappings)).size());
    }
}

[stevehu]

@jawaff I don't mind if you check into the same branch and this might be the most efficient way to work together. However, if you don't feel comfortable, could you please approve the PR and you can start another one after the merge. Thanks.

[andersonf]

@stevehu, I liked the way you handle which commands are implemented for each schema using the position of bits. Thanks for the documentation and all your effort. This change will make it even easier to add new commands.

[stevehu]

@andersonf @jawaff Thanks a lot for the reviews and feedbacks. I have merged this PR. Please submit the PRs for the test runner and if-else-then. Contribution credits need to go to the contributors :)

[jawaff]

@stevehu This was such a great change. Thanks for the effort, Steve. I'll look into making a pull request later today or tomorrow.

[stevehu]

@jawaff I was inspired by the ideas you suggested.