/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed 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
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, 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.springframework.http.converter.json;

import java.io.IOException;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.ObjectMapper;

import org.springframework.http.MediaType;
import org.springframework.lang.Nullable;

Implementation of HttpMessageConverter that can read and write JSON using Jackson 2.x's ObjectMapper. 
This converter can be used to bind to typed beans, or untyped HashMap instances. 
By default, this converter supports application/json and application/*+json with UTF-8 character set. This can be overridden by setting the supportedMediaTypes property. 
The default constructor uses the default configuration provided by Jackson2ObjectMapperBuilder. 
Compatible with Jackson 2.9 and higher, as of Spring 5.0.
Author:
Arjen Poutsma, Keith Donald, Rossen Stoyanchev, Juergen Hoeller, Sebastien Deleuze
Since:
3.1.2/**
 * Implementation of {@link org.springframework.http.converter.HttpMessageConverter} that can read and
 * write JSON using <a href="http://wiki.fasterxml.com/JacksonHome">Jackson 2.x's</a> {@link ObjectMapper}.
 *
 * <p>This converter can be used to bind to typed beans, or untyped {@code HashMap} instances.
 *
 * <p>By default, this converter supports {@code application/json} and {@code application/*+json}
 * with {@code UTF-8} character set. This can be overridden by setting the
 * {@link #setSupportedMediaTypes supportedMediaTypes} property.
 *
 * <p>The default constructor uses the default configuration provided by {@link Jackson2ObjectMapperBuilder}.
 *
 * <p>Compatible with Jackson 2.9 and higher, as of Spring 5.0.
 *
 * @author Arjen Poutsma
 * @author Keith Donald
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @author Sebastien Deleuze
 * @since 3.1.2
 */
public class MappingJackson2HttpMessageConverter extends AbstractJackson2HttpMessageConverter {

	@Nullable
	private String jsonPrefix;


	
Construct a new MappingJackson2HttpMessageConverter using default configuration provided by Jackson2ObjectMapperBuilder. /**
	 * Construct a new {@link MappingJackson2HttpMessageConverter} using default configuration
	 * provided by {@link Jackson2ObjectMapperBuilder}.
	 */
	public MappingJackson2HttpMessageConverter() {
		this(Jackson2ObjectMapperBuilder.json().build());
	}

	
Construct a new MappingJackson2HttpMessageConverter with a custom ObjectMapper. You can use Jackson2ObjectMapperBuilder to build it easily. 
See Also:
Jackson2ObjectMapperBuilder.json()/**
	 * Construct a new {@link MappingJackson2HttpMessageConverter} with a custom {@link ObjectMapper}.
	 * You can use {@link Jackson2ObjectMapperBuilder} to build it easily.
	 * @see Jackson2ObjectMapperBuilder#json()
	 */
	public MappingJackson2HttpMessageConverter(ObjectMapper objectMapper) {
		super(objectMapper, MediaType.APPLICATION_JSON, new MediaType("application", "*+json"));
	}


	
Specify a custom prefix to use for this view's JSON output.
Default is none.
See Also:
setPrefixJson/**
	 * Specify a custom prefix to use for this view's JSON output.
	 * Default is none.
	 * @see #setPrefixJson
	 */
	public void setJsonPrefix(String jsonPrefix) {
		this.jsonPrefix = jsonPrefix;
	}

	
Indicate whether the JSON output by this view should be prefixed with ")]}', ". Default is false.
Prefixing the JSON string in this manner is used to help prevent JSON Hijacking.
The prefix renders the string syntactically invalid as a script so that it cannot be hijacked.
This prefix should be stripped before parsing the string as JSON.
See Also:
setJsonPrefix/**
	 * Indicate whether the JSON output by this view should be prefixed with ")]}', ". Default is false.
	 * <p>Prefixing the JSON string in this manner is used to help prevent JSON Hijacking.
	 * The prefix renders the string syntactically invalid as a script so that it cannot be hijacked.
	 * This prefix should be stripped before parsing the string as JSON.
	 * @see #setJsonPrefix
	 */
	public void setPrefixJson(boolean prefixJson) {
		this.jsonPrefix = (prefixJson ? ")]}', " : null);
	}


	@Override
	protected void writePrefix(JsonGenerator generator, Object object) throws IOException {
		if (this.jsonPrefix != null) {
			generator.writeRaw(this.jsonPrefix);
		}
	}

}