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 * Licensed to the Apache Software Foundation (ASF) under one   *
 * or more contributor license agreements.  See the NOTICE file *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
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 *   http://www.apache.org/licenses/LICENSE-2.0                 *
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 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
 * specific language governing permissions and limitations      *
 * under the License.                                           *
 ****************************************************************/

package org.apache.james.webadmin.utils;

import java.util.Collection;
import java.util.Set;
import java.util.stream.Collectors;

import javax.inject.Inject;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.guava.GuavaModule;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.google.common.collect.ImmutableSet;
import spark.ResponseTransformer;

public class JsonTransformer implements ResponseTransformer {

    private final ObjectMapper objectMapper;

    public JsonTransformer(JsonTransformerModule... modules) {
        this(ImmutableSet.copyOf(modules));
    }

    @Inject
    public JsonTransformer(Set<JsonTransformerModule> jsonTransformerModules) {
        this(jsonTransformerModules
            .stream()
            .map(JsonTransformerModule::asJacksonModule)
            .collect(Collectors.toList()));
    }

    private JsonTransformer(Collection<Module> modules) {
        objectMapper = new ObjectMapper()
            .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false)
            .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
            .registerModule(new Jdk8Module())
            .registerModule(new JavaTimeModule())
            .registerModule(new GuavaModule())
            .registerModules(modules);
    }

    @Override
    public String render(Object o) throws JsonProcessingException {
        return objectMapper.writeValueAsString(o);
    }
}
