org.springframework.boot.test.json.JacksonTester.java Source code

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Here is the source code for org.springframework.boot.test.json.JacksonTester.java

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/*
 * Copyright 2012-2019 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
 *
 *      https://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.boot.test.json;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;

import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.spi.json.JacksonJsonProvider;
import com.jayway.jsonpath.spi.mapper.JacksonMappingProvider;

import org.springframework.beans.factory.ObjectFactory;
import org.springframework.core.ResolvableType;
import org.springframework.util.Assert;

/**
 * AssertJ based JSON tester backed by Jackson. Usually instantiated via
 * {@link #initFields(Object, ObjectMapper)}, for example: <pre class="code">
 * public class ExampleObjectJsonTests {
 *
 *     private JacksonTester&lt;ExampleObject&gt; json;
 *
 *     &#064;Before
 *     public void setup() {
 *         ObjectMapper objectMapper = new ObjectMapper();
 *         JacksonTester.initFields(this, objectMapper);
 *     }
 *
 *     &#064;Test
 *     public void testWriteJson() throws IOException {
 *         ExampleObject object = //...
 *         assertThat(json.write(object)).isEqualToJson("expected.json");
 *     }
 *
 * }
 * </pre>
 *
 * See {@link AbstractJsonMarshalTester} for more details.
 *
 * @param <T> the type under test
 * @author Phillip Webb
 * @author Madhura Bhave
 * @author Diego Berrueta
 * @since 1.4.0
 */
public class JacksonTester<T> extends AbstractJsonMarshalTester<T> {

    private final ObjectMapper objectMapper;

    private Class<?> view;

    /**
     * Create a new {@link JacksonTester} instance.
     * @param objectMapper the Jackson object mapper
     */
    protected JacksonTester(ObjectMapper objectMapper) {
        Assert.notNull(objectMapper, "ObjectMapper must not be null");
        this.objectMapper = objectMapper;
    }

    /**
     * Create a new {@link JacksonTester} instance.
     * @param resourceLoadClass the source class used to load resources
     * @param type the type under test
     * @param objectMapper the Jackson object mapper
     */
    public JacksonTester(Class<?> resourceLoadClass, ResolvableType type, ObjectMapper objectMapper) {
        this(resourceLoadClass, type, objectMapper, null);
    }

    public JacksonTester(Class<?> resourceLoadClass, ResolvableType type, ObjectMapper objectMapper,
            Class<?> view) {
        super(resourceLoadClass, type);
        Assert.notNull(objectMapper, "ObjectMapper must not be null");
        this.objectMapper = objectMapper;
        this.view = view;
    }

    @Override
    protected JsonContent<T> getJsonContent(String json) {
        Configuration configuration = Configuration.builder()
                .jsonProvider(new JacksonJsonProvider(this.objectMapper))
                .mappingProvider(new JacksonMappingProvider(this.objectMapper)).build();
        return new JsonContent<>(getResourceLoadClass(), getType(), json, configuration);
    }

    @Override
    protected T readObject(InputStream inputStream, ResolvableType type) throws IOException {
        return getObjectReader(type).readValue(inputStream);
    }

    @Override
    protected T readObject(Reader reader, ResolvableType type) throws IOException {
        return getObjectReader(type).readValue(reader);
    }

    private ObjectReader getObjectReader(ResolvableType type) {
        ObjectReader objectReader = this.objectMapper.readerFor(getType(type));
        if (this.view != null) {
            return objectReader.withView(this.view);
        }
        return objectReader;
    }

    @Override
    protected String writeObject(T value, ResolvableType type) throws IOException {
        return getObjectWriter(type).writeValueAsString(value);
    }

    private ObjectWriter getObjectWriter(ResolvableType type) {
        ObjectWriter objectWriter = this.objectMapper.writerFor(getType(type));
        if (this.view != null) {
            return objectWriter.withView(this.view);
        }
        return objectWriter;
    }

    private JavaType getType(ResolvableType type) {
        return this.objectMapper.constructType(type.getType());
    }

    /**
     * Utility method to initialize {@link JacksonTester} fields. See {@link JacksonTester
     * class-level documentation} for example usage.
     * @param testInstance the test instance
     * @param objectMapper the object mapper
     * @see #initFields(Object, ObjectMapper)
     */
    public static void initFields(Object testInstance, ObjectMapper objectMapper) {
        new JacksonFieldInitializer().initFields(testInstance, objectMapper);
    }

    /**
     * Utility method to initialize {@link JacksonTester} fields. See {@link JacksonTester
     * class-level documentation} for example usage.
     * @param testInstance the test instance
     * @param objectMapperFactory a factory to create the object mapper
     * @see #initFields(Object, ObjectMapper)
     */
    public static void initFields(Object testInstance, ObjectFactory<ObjectMapper> objectMapperFactory) {
        new JacksonFieldInitializer().initFields(testInstance, objectMapperFactory);
    }

    /**
     * Returns a new instance of {@link JacksonTester} with the view that should be used
     * for json serialization/deserialization.
     * @param view the view class
     * @return the new instance
     */
    public JacksonTester<T> forView(Class<?> view) {
        return new JacksonTester<>(this.getResourceLoadClass(), this.getType(), this.objectMapper, view);
    }

    /**
     * {@link FieldInitializer} for Jackson.
     */
    private static class JacksonFieldInitializer extends FieldInitializer<ObjectMapper> {

        protected JacksonFieldInitializer() {
            super(JacksonTester.class);
        }

        @Override
        protected AbstractJsonMarshalTester<Object> createTester(Class<?> resourceLoadClass, ResolvableType type,
                ObjectMapper marshaller) {
            return new JacksonTester<>(resourceLoadClass, type, marshaller);
        }

    }

}