com.netflix.zeno.serializer.SerializationFramework Maven / Gradle / Ivy

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/*
 *
 *  Copyright 2013 Netflix, Inc.
 *
 *     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.netflix.zeno.serializer;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * An implementation of the abstract class SerializationFramework will describe some operation
 * that can be performed on data in a semantically and structurally agnostic way.
 *
 * For a given POJO model, a set of {@link NFTypeSerializer} implementations must be created to describe their
 * structure.  A set of serializers, identified by a SerializerFactory, is passed into the constructor
 * of this Object.

 *
 * The SerializationFramework implementation will traverse this hierarchy of serializers in order to
 * perform its operation.

 *
 * Example implementations of SerializationFramework are:

 *
 * HashSerializationFramework:     Calculates an MD5 sum for POJOs conforming to the NFTypeSerializers.

 * JsonSerializationFramework:     Translates POJOs to json (and vice versa)

 * FastBlobSerializationFramework: Creates binary dumps of data states represented by POJOs

 *
 * By maintaining a clean separation of data semantics / structure and the operations which can be performed
 * on the data, we avoid multiplying the work required to maintain our data model by the number of operations
 * we can perform.
 *
 * Supporting new functionality is easy; we can define a new SerializationFramework.  Adding to the data model
 * is easy; we simply create / modify {@link NFTypeSerializer}s
 *
 * For details about how to create new SerializationFramework implementations, check out the section 
 * creating new operations in the 
 * Zeno documentation.
 * 
 * @author dkoszewnik
 *
 */
public abstract class SerializationFramework {

    protected FrameworkSerializer frameworkSerializer;
    protected FrameworkDeserializer frameworkDeserializer;
    protected NFTypeSerializer[] topLevelSerializers;
    private final Map> serializers = new HashMap>();

    /// The NFTypeSerializers, ordered such that all dependencies come *before* their dependents
    private final List> orderedSerializers = new ArrayList>();

    public SerializationFramework(SerializerFactory serializerFactory) {
        this.topLevelSerializers = serializerFactory.createSerializers();
        addSerializerTree(topLevelSerializers);
    }

    private void addSerializerTree(NFTypeSerializer... topLevelSerializers) {
        Set alreadyAddedSerializers = new HashSet();
        for(NFTypeSerializer serializer : topLevelSerializers) {
            addSerializer(serializer, alreadyAddedSerializers, true);
        }
    }

    private void addSerializer(NFTypeSerializer serializer, SetalreadyAddedSerializers, boolean topLevelSerializer) {
        if(firstTimeSeeingSerializer(serializer, alreadyAddedSerializers)) {
            for(NFTypeSerializer subSerializer : serializer.requiredSubSerializers()) {
                addSerializer(subSerializer, alreadyAddedSerializers, false);
            }

            serializer.setSerializationFramework(this);
            serializers.put(serializer.getName(), serializer);
            orderedSerializers.add(serializer);
        }
    }

    private boolean firstTimeSeeingSerializer(NFTypeSerializer serializer, SetalreadyAddedSerializers) {
        if(!alreadyAddedSerializers.contains(serializer.getName())) {
            alreadyAddedSerializers.add(serializer.getName());
            return true;
        }
        return false;
    }

    @SuppressWarnings("rawtypes")
    public FrameworkSerializer getFrameworkSerializer() {
        return frameworkSerializer;
    }

    @SuppressWarnings("rawtypes")
    public FrameworkDeserializer getFrameworkDeserializer() {
        return frameworkDeserializer;
    }

    /**
     * @return the NFTypeSerializers ordered such that dependencies come *before* their dependents.
     */
    public List> getOrderedSerializers() {
        return orderedSerializers;
    }

    @SuppressWarnings("unchecked")
    public  NFTypeSerializer getSerializer(String typeName) {
        return (NFTypeSerializer) serializers.get(typeName);
    }

    public NFTypeSerializer[] getTopLevelSerializers() {
        return topLevelSerializers;
    }

}