org.oncoblocks.centromere.web.util.FilteringJackson2HttpMessageConverter.java Source code

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Here is the source code for org.oncoblocks.centromere.web.util.FilteringJackson2HttpMessageConverter.java

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/*
 * Copyright 2016 William Oemler, Blueprint Medicines
 *
 * 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.oncoblocks.centromere.web.util;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ser.FilterProvider;
import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
import org.oncoblocks.centromere.web.controller.ResponseEnvelope;
import org.springframework.hateoas.ResourceSupport;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;

import java.io.IOException;
import java.lang.reflect.Type;
import java.util.Set;

/**
 * Uses {@link org.oncoblocks.centromere.web.controller.ResponseEnvelope} to identify filterable entities and 
 *   filters or includes fields based upon request parameters.
 * 
 * @author woemler 
 */

public class FilteringJackson2HttpMessageConverter extends MappingJackson2HttpMessageConverter {

    private boolean prefixJson = false;

    @Override
    public void setPrefixJson(boolean prefixJson) {
        this.prefixJson = prefixJson;
        super.setPrefixJson(prefixJson);
    }

    @Override
    protected void writeInternal(Object object, Type type, HttpOutputMessage outputMessage)
            throws IOException, HttpMessageNotWritableException {

        ObjectMapper objectMapper = getObjectMapper();
        JsonGenerator jsonGenerator = objectMapper.getFactory().createGenerator(outputMessage.getBody());

        try {

            if (this.prefixJson) {
                jsonGenerator.writeRaw(")]}', ");
            }

            if (object instanceof ResponseEnvelope) {

                ResponseEnvelope envelope = (ResponseEnvelope) object;
                Object entity = envelope.getEntity();
                Set<String> fieldSet = envelope.getFieldSet();
                Set<String> exclude = envelope.getExclude();
                FilterProvider filters = null;

                if (fieldSet != null && !fieldSet.isEmpty()) {
                    if (entity instanceof ResourceSupport) {
                        fieldSet.add("content"); // Don't filter out the wrapped content.
                    }
                    filters = new SimpleFilterProvider()
                            .addFilter("fieldFilter", SimpleBeanPropertyFilter.filterOutAllExcept(fieldSet))
                            .setFailOnUnknownId(false);
                } else if (exclude != null && !exclude.isEmpty()) {
                    filters = new SimpleFilterProvider()
                            .addFilter("fieldFilter", SimpleBeanPropertyFilter.serializeAllExcept(exclude))
                            .setFailOnUnknownId(false);
                } else {
                    filters = new SimpleFilterProvider()
                            .addFilter("fieldFilter", SimpleBeanPropertyFilter.serializeAllExcept())
                            .setFailOnUnknownId(false);
                }

                objectMapper.setFilterProvider(filters);
                objectMapper.writeValue(jsonGenerator, entity);

            } else if (object == null) {
                jsonGenerator.writeNull();
            } else {
                FilterProvider filters = new SimpleFilterProvider().setFailOnUnknownId(false);
                objectMapper.setFilterProvider(filters);
                objectMapper.writeValue(jsonGenerator, object);
            }

        } catch (JsonProcessingException e) {
            e.printStackTrace();
            throw new HttpMessageNotWritableException("Could not write JSON: " + e.getMessage());
        }

    }
}