com.meltmedia.jackson.crypto.EncryptedJsonSerializer.java Source code

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Here is the source code for com.meltmedia.jackson.crypto.EncryptedJsonSerializer.java

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/**
 * Copyright (C) 2014 meltmedia (christian.trimble@meltmedia.com)
 *
 * 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 com.meltmedia.jackson.crypto;

import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;

public class EncryptedJsonSerializer extends JsonSerializer<Object> {

    private JsonSerializer<Object> baseSer;
    private EncryptionService<EncryptedJson> service;
    private Encrypted annotation;

    public EncryptedJsonSerializer(EncryptionService<EncryptedJson> service, Encrypted annotation,
            JsonSerializer<Object> baseSer) {
        this.service = service;
        this.annotation = annotation;
        this.baseSer = baseSer;
    }

    @Override
    public void serialize(Object object, JsonGenerator generator, SerializerProvider provider)
            throws IOException, JsonProcessingException {

        StringWriter writer = new StringWriter();
        JsonGenerator nestedGenerator = generator.getCodec().getFactory().createGenerator(writer);
        if (baseSer == null) {
            provider.defaultSerializeValue(object, nestedGenerator);
        } else {
            baseSer.serialize(object, nestedGenerator, provider);
        }
        nestedGenerator.close();
        String value = writer.getBuffer().toString();
        EncryptedJson encrypted = service.encrypt(value, this.annotation.encoding());
        generator.writeObject(encrypted);
    }

    public static class Modifier extends BeanSerializerModifier {
        private Map<String, EncryptionService<EncryptedJson>> sourceMap = new LinkedHashMap<>();

        public Modifier() {
        }

        public Modifier addSource(EncryptionService<EncryptedJson> source) {
            sourceMap.put(source.getName(), source);
            return this;
        }

        // we do not need to override this.
        @Override
        public List<BeanPropertyWriter> changeProperties(SerializationConfig config, BeanDescription beanDesc,
                List<BeanPropertyWriter> beanProperties) {
            List<BeanPropertyWriter> newWriters = new ArrayList<BeanPropertyWriter>();
            for (BeanPropertyWriter writer : beanProperties) {
                Encrypted encrypted = writer.getAnnotation(Encrypted.class);
                if (encrypted == null) {
                    newWriters.add(writer);
                    continue;
                }

                String source = encrypted.source();
                EncryptionService<EncryptedJson> service = sourceMap.get(source);
                if (service == null) {
                    throw new IllegalArgumentException(
                            String.format("No encryption key source defined for %s.", source));
                }

                JsonSerializer<Object> currentSer = writer.getSerializer();
                JsonSerializer<Object> encryptSer = new EncryptedJsonSerializer(service, encrypted, currentSer);
                newWriters.add(new EncryptedPropertyWriter(writer, encryptSer));
            }
            return newWriters;
        }

    }

    static class EncryptedPropertyWriter extends BeanPropertyWriter {

        public EncryptedPropertyWriter(BeanPropertyWriter toCopy, JsonSerializer<Object> deser) {
            super(toCopy);
            this._serializer = deser;
        }
    }

}