FilteringParserDelegate cannot deserialize empty list

[xiazuojie]

This is a follow up issue of #700 .

If using FilteringParserDelegate to filter out a part of json, it throws the following exception when the input json is an empty list ("[]").

com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
 at [Source: (byte[])"[]"; line: 1, column: 2]

	at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
	at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:4688)
	at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:4561)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2823)
	at com.alibaba.dapr.serialization.json.FilteringParserDelegateTest.testFilteringParserDelegateWithEmptyList(FilteringParserDelegateTest.java:36)

Test case:

package com.alibaba.dapr.serialization.json;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.filter.FilteringParserDelegate;
import com.fasterxml.jackson.core.filter.TokenFilter;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.Test;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;

import static org.junit.Assert.assertTrue;

public class FilteringParserDelegateTest {
    @Test
    public void testFilteringParserDelegateWithEmptyList() throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        final TokenFilter tokenFilter = new TokenFilter() {
            @Override
            public TokenFilter includeProperty(String name) {
                if ("@type".equals(name)) {
                    return null;
                }
                return INCLUDE_ALL;
            }
        };

        byte[] content = "[]".getBytes(StandardCharsets.UTF_8);

        JsonParser jp = mapper.createParser(content);
        JsonParser jsonParser = new FilteringParserDelegate(jp, tokenFilter, TokenFilter.Inclusion.INCLUDE_ALL_AND_PATH, true);

        List<Map<String, String>> a = mapper.readValue(jsonParser, new TypeReference<List<Map<String, String>>>() {});
        assertTrue(a.isEmpty());
    }
}

Jackson version: 2.12.3

[cowtowncoder]

Interesting... empty array (and empty Object) are sort of edge cases since they are leaf values on their own.

Will need to think of what to do with them; almost certainly need to add 2 more callback methods in TokenFilter.
I hope to be able to fix this before 2.13.0 final but that may take time.

Will add failing tests first.

[cowtowncoder]

Resolved via #715, to be included in 2.14.0. Closing this as dup (just for convenience as PR was pointing to the other issue).