ca.derekcormier.recipe.Oven Maven / Gradle / Ivy

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Java runtime classes for the Recipe framework
There is a newer version: 0.4.0
package ca.derekcormier.recipe;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.jsontype.NamedType;
import com.fasterxml.jackson.databind.jsontype.SubtypeResolver;
import com.fasterxml.jackson.databind.jsontype.impl.StdSubtypeResolver;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Oven extends AbstractOven {
    private Map dispatchers = new HashMap<>();
    private ObjectMapper objectMapper;
    private SubtypeResolver subtypeResolver;

    public Cake bake(Recipe recipe) {
        this.subtypeResolver = new StdSubtypeResolver();

        registerSubtypes(recipe);

        objectMapper = new ObjectMapper();
        objectMapper.setSubtypeResolver(subtypeResolver);

        Cake cake = _bake(recipe, createCake());
        return cake;
    }

    private Cake _bake(Recipe recipe, Cake cake) {
        try {
            List segments = recipe.segment();
            for (Recipe.Segment segment: segments) {
                String payload = serializePayload(segment.recipe, cake);

                if (!dispatchers.containsKey(segment.domain)) {
                    throw new RuntimeException("cannot dispatch ingredient; no dispatcher registered for domain '" + segment.domain + "'");
                }

                String jsonCake = dispatchers.get(segment.domain).dispatch(payload);
                cake = deserializeCake(jsonCake);
            }
            return cake;
        }
        catch (Exception e) {
            throw new RuntimeException("could not bake cake", e);
        }
    }

    public void addDispatcher(String domain, Dispatcher dispatcher) {
        if (dispatchers.containsKey(domain)) {
            throw new RuntimeException("oven already has a dispatcher for domain '" + domain + "'");
        }

        dispatchers.put(domain, dispatcher);
    }

    private String serializePayload(Recipe recipe, Cake cake) throws JsonProcessingException {
        Cake plainCake = new Cake();
        plainCake.setEntries(cake.getEntries());
        Payload payload = new Payload(recipe, plainCake);
        return objectMapper.writeValueAsString(payload);
    }

    private Cake deserializeCake(String json) throws IOException {
        Cake plainCake = objectMapper.readValue(json, Cake.class);
        Cake cake = createCake();
        cake.setEntries(plainCake.getEntries());
        return cake;
    }

    private void registerSubtypes(Recipe recipe) {
        for (Ingredient ingredient: recipe.getIngredients()) {
            if (ingredient instanceof Recipe) {
                registerSubtypes((Recipe)ingredient);
            }
            else {
                subtypeResolver.registerSubtypes(new NamedType(ingredient.getClass(), ingredient.getIngredientType()));
            }
        }
    }
}