Example usage for com.google.gson.internal Streams parse

Introduction

In this page you can find the example usage for com.google.gson.internal Streams parse.

Prototype

public static JsonElement parse(JsonReader reader) throws JsonParseException

Source Link

Document

Takes a reader in any state and returns the next value as a JsonElement.

Usage

From source file:ca.ualberta.cs.team1travelexpenseapp.gsonUtils.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }/*from w  w  w. j  a v a2s  . c  om*/

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().remove(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            if (jsonObject.has(typeFieldName)) {
                throw new JsonParseException("cannot serialize " + srcType.getName()
                        + " because it already defines a field named " + typeFieldName);
            }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    };
}

From source file:cc.kave.commons.utils.json.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }/*from  w  w w  .j av a  2  s  .  c o m*/

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            // (kave adaptation) was: ".remove(typeFiledName)"
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().get(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that
            // subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            if (value == null) {
                Streams.write(null, out);
                return;
            }
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that
            // subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            // (kave adaptation) disabled check
            // if (jsonObject.has(typeFieldName)) {
            // throw new JsonParseException("cannot serialize " +
            // srcType.getName()
            // + " because it already defines a field named " +
            // typeFieldName);
            // }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    };
}

From source file:com.builtbroken.builder.utils.Utils.java

/**
 * Reads a file from disk as a json element
 *
 * @param file - file to load, does not check if the
 *             file exists or is a json file.
 * @return element/*from   w w  w .  j a va  2  s  . c om*/
 */
public static JsonElement toJsonElement(final File file) {
    try {
        FileReader stream = new FileReader(file);
        BufferedReader reader = new BufferedReader(stream);

        JsonReader jsonReader = new JsonReader(reader);
        JsonElement element = Streams.parse(jsonReader);

        reader.close();
        stream.close();
        return element;
    } catch (Exception e) {
        throw new RuntimeException("Failed to parse file as json [" + file + "]", e);
    }
}

From source file:com.devicehive.json.adapters.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }//from w  w w  . j av  a 2  s .c  om

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            //                JsonElement labelJsonElement = jsonElement.getAsJsonObject().remove(typeFieldName);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().get(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            //                if (jsonObject.has(typeFieldName)) {
            //                    throw new JsonParseException("cannot serialize " + srcType.getName()
            //                            + " because it already defines a field named " + typeFieldName);
            //                }
            //                JsonObject clone = new JsonObject();
            //                clone.add(typeFieldName, new JsonPrimitive(label));
            //                for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
            //                    clone.add(e.getKey(), e.getValue());
            //                }
            //                Streams.write(clone, out);
            Streams.write(jsonObject, out);
        }
    }.nullSafe();
}

From source file:com.etermax.conversations.repository.impl.elasticsearch.mapper.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }// www.  j av  a2 s . com

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().remove(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            if (jsonObject.has(typeFieldName)) {
                throw new JsonParseException("cannot serialize " + srcType.getName()
                        + " because it already defines a field named " + typeFieldName);
            }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    }.nullSafe();
}

From source file:com.github.kyriosdata.regras.infraestrutura.CustomRegraTypeAdapterFactory.java

License:Creative Commons License

@Override
public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) {
    if (type.getRawType() != Regra.class)
        return null;

    final TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);

    return new TypeAdapter<T>() {
        @Override/*from w w w  .j  a v  a 2 s.c  o  m*/
        public void write(final JsonWriter jsonWriter, final T t) throws IOException {
            jsonWriter.beginObject();
            jsonWriter.name("tipo");
            jsonWriter.value(getTipo(t.getClass().getName()));
            jsonWriter.name("obj");
            delegate.write(jsonWriter, t);
            jsonWriter.endObject();
        }

        @Override
        public T read(final JsonReader jsonReader) throws IOException, JsonParseException {
            JsonElement tree = Streams.parse(jsonReader);
            JsonObject object = tree.getAsJsonObject();

            String clazz = object.get("tipo").getAsString();
            JsonElement obj = object.get("obj").getAsJsonObject();

            if ("expressao".equals(clazz)) {
                return (T) gson.getDelegateAdapter(CustomRegraTypeAdapterFactory.this,
                        TypeToken.get(RegraExpressao.class)).fromJsonTree(obj);
            }

            if ("pontosPorRelato".equals(clazz)) {
                return (T) gson.getDelegateAdapter(CustomRegraTypeAdapterFactory.this,
                        TypeToken.get(RegraPontosPorRelato.class)).fromJsonTree(obj);
            }

            throw new JsonParseException("Erro ao desserializar " + type + ". No  uma regra?");
        }
    };
}

From source file:com.github.sheigutn.pushbullet.gson.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }//from   w w  w. j av  a  2 s  .  c o  m

    if (baseDelegateAdapter == null) {
        baseDelegateAdapter = gson.getDelegateAdapter(RuntimeTypeAdapterFactory.this, TypeToken.get(baseType));
    }

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @SuppressWarnings("unchecked")
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().get(typeFieldName); //remove(typeFieldName) changed to get(typeFieldName)
            if (labelJsonElement == null) {
                return (R) baseDelegateAdapter.fromJsonTree(jsonElement);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            //if (jsonObject.has(typeFieldName)) {
            //    throw new JsonParseException("cannot serialize " + srcType.getName()
            //            + " because it already defines a field named " + typeFieldName); <-- Commented
            //}
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    }.nullSafe();
}

From source file:com.gsaul.AethonSimulator.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }/*w  ww .j a va 2  s .c o m*/

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().get(typeFieldName); //used to be .remove(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            if (jsonObject.has(typeFieldName)) {
                throw new JsonParseException("cannot serialize " + srcType.getName()
                        + " because it already defines a field named " + typeFieldName);
            }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    }.nullSafe();
}

From source file:com.kotcrab.vis.editor.serializer.json.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (baseType.isAssignableFrom(type.getRawType()) == false) {
        return null;
    }/*from  w  ww  .j a v  a 2s.c  o m*/

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().remove(typeFieldName);
            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            if (jsonObject.has(typeFieldName)) {
                throw new JsonParseException("cannot serialize " + srcType.getName()
                        + " because it already defines a field named " + typeFieldName);
            }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    };
}

From source file:com.learn.mobile.library.dmobi.helper.RuntimeTypeAdapterFactory.java

License:Apache License

public <R> TypeAdapter<R> create(Gson gson, TypeToken<R> type) {
    if (type.getRawType() != baseType) {
        return null;
    }/*from ww w .  j  a v a  2  s .co m*/

    final Map<String, TypeAdapter<?>> labelToDelegate = new LinkedHashMap<String, TypeAdapter<?>>();
    final Map<Class<?>, TypeAdapter<?>> subtypeToDelegate = new LinkedHashMap<Class<?>, TypeAdapter<?>>();
    for (Map.Entry<String, Class<?>> entry : labelToSubtype.entrySet()) {
        TypeAdapter<?> delegate = gson.getDelegateAdapter(this, TypeToken.get(entry.getValue()));
        labelToDelegate.put(entry.getKey(), delegate);
        subtypeToDelegate.put(entry.getValue(), delegate);
    }

    return new TypeAdapter<R>() {
        @Override
        public R read(JsonReader in) throws IOException {
            JsonElement jsonElement = Streams.parse(in);
            // JsonElement labelJsonElement = jsonElement.getAsJsonObject().remove(typeFieldName);
            // Do not remove typeFieldName
            JsonElement labelJsonElement = jsonElement.getAsJsonObject().get(typeFieldName);

            if (labelJsonElement == null) {
                throw new JsonParseException("cannot deserialize " + baseType
                        + " because it does not define a field named " + typeFieldName);
            }
            String label = labelJsonElement.getAsString();
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) labelToDelegate.get(label);
            if (delegate == null) {
                throw new JsonParseException("cannot deserialize " + baseType + " subtype named " + label
                        + "; did you forget to register a subtype?");
            }
            return delegate.fromJsonTree(jsonElement);
        }

        @Override
        public void write(JsonWriter out, R value) throws IOException {
            Class<?> srcType = value.getClass();
            String label = subtypeToLabel.get(srcType);
            @SuppressWarnings("unchecked") // registration requires that subtype extends T
            TypeAdapter<R> delegate = (TypeAdapter<R>) subtypeToDelegate.get(srcType);
            if (delegate == null) {
                throw new JsonParseException(
                        "cannot serialize " + srcType.getName() + "; did you forget to register a subtype?");
            }
            JsonObject jsonObject = delegate.toJsonTree(value).getAsJsonObject();
            if (jsonObject.has(typeFieldName)) {
                throw new JsonParseException("cannot serialize " + srcType.getName()
                        + " because it already defines a field named " + typeFieldName);
            }
            JsonObject clone = new JsonObject();
            clone.add(typeFieldName, new JsonPrimitive(label));
            for (Map.Entry<String, JsonElement> e : jsonObject.entrySet()) {
                clone.add(e.getKey(), e.getValue());
            }
            Streams.write(clone, out);
        }
    }.nullSafe();
}