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Java bindings for the AWS IoT Core Service
/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
package software.amazon.awssdk.eventstreamrpc;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import software.amazon.awssdk.eventstreamrpc.model.AccessDeniedException;
import software.amazon.awssdk.eventstreamrpc.model.EventStreamJsonMessage;
import software.amazon.awssdk.eventstreamrpc.model.UnsupportedOperationException;
import software.amazon.awssdk.eventstreamrpc.model.ValidationException;
import software.amazon.awssdk.crt.utils.StringUtils;
import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;
import java.time.Instant;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
/**
* Implementers of this service model are expected to likely be singletons. There
* should be little value to having more than one, though between different instances
* properly constructed for a service, they can be used interchangeably
*/
public abstract class EventStreamRPCServiceModel {
private static final Gson GSON;
/**
* Version header string
*/
static final String VERSION_HEADER = ":version";
/**
* Content type header string
*/
public static final String CONTENT_TYPE_HEADER = ":content-type";
/**
* Content type application text string
*/
public static final String CONTENT_TYPE_APPLICATION_TEXT = "text/plain";
/**
* Content type application json string
*/
public static final String CONTENT_TYPE_APPLICATION_JSON = "application/json";
/**
* Service model type header
*/
public static final String SERVICE_MODEL_TYPE_HEADER = "service-model-type";
static {
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapterFactory(new ForceNullsForMapTypeAdapterFactory());
builder.registerTypeAdapterFactory(OptionalTypeAdapter.FACTORY);
builder.registerTypeAdapterFactory(EventStreamPostFromJsonTypeAdapter.FACTORY);
builder.registerTypeAdapter(byte[].class, new Base64BlobSerializerDeserializer());
builder.registerTypeAdapter(Instant.class, new InstantSerializerDeserializer());
builder.excludeFieldsWithoutExposeAnnotation();
GSON = builder.create();
}
// Type adapter to automatically call "postFromJson" on all instances of EventStreamJsonMessage we construct
private static class EventStreamPostFromJsonTypeAdapter extends TypeAdapter {
public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
@Override
public TypeAdapter create(Gson gson, TypeToken type) {
if (EventStreamJsonMessage.class.isAssignableFrom(type.getRawType())) {
final TypeAdapter delegate = gson.getDelegateAdapter(this, type);
return new EventStreamPostFromJsonTypeAdapter(delegate);
}
return null;
}
};
private final TypeAdapter adapter;
public EventStreamPostFromJsonTypeAdapter(TypeAdapter adapter) {
this.adapter = adapter;
}
@Override
public void write(JsonWriter out, E value) throws IOException {
adapter.write(out, value);
}
@Override
public E read(JsonReader in) throws IOException {
E obj = adapter.read(in);
if (obj != null) {
// Call postFromJson to finalize the deserialization. Especially important for unions to have their
// member get set correctly.
obj.postFromJson();
}
return obj;
}
}
private static class ForceNullsForMapTypeAdapterFactory implements TypeAdapterFactory {
public final TypeAdapter create(Gson gson, TypeToken type) {
if (Map.class.isAssignableFrom(type.getRawType())) {
final TypeAdapter delegate = gson.getDelegateAdapter(this, type);
return createCustomTypeAdapter(delegate);
}
return null;
}
private TypeAdapter createCustomTypeAdapter(TypeAdapter delegate) {
return new TypeAdapter() {
@Override
public void write(JsonWriter out, T value) throws IOException {
final boolean serializeNulls = out.getSerializeNulls();
try {
out.setSerializeNulls(true);
delegate.write(out, value);
} finally {
out.setSerializeNulls(serializeNulls);
}
}
@Override
public T read(JsonReader in) throws IOException {
return delegate.read(in);
}
};
}
}
private static class OptionalTypeAdapter extends TypeAdapter> {
public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
@Override
public TypeAdapter create(Gson gson, TypeToken type) {
Class rawType = (Class) type.getRawType();
if (rawType != Optional.class) {
return null;
}
final ParameterizedType parameterizedType = (ParameterizedType) type.getType();
final Type actualType = parameterizedType.getActualTypeArguments()[0];
final TypeAdapter adapter = gson.getAdapter(TypeToken.get(actualType));
return new OptionalTypeAdapter(adapter);
}
};
private final TypeAdapter adapter;
public OptionalTypeAdapter(TypeAdapter adapter) {
this.adapter = adapter;
}
@Override
public void write(JsonWriter out, Optional value) throws IOException {
if (value.isPresent()){
adapter.write(out, value.get());
} else if (value != null) {
out.nullValue();
} else { }
}
@Override
public Optional read(JsonReader in) throws IOException {
return Optional.ofNullable(adapter.read(in));
}
}
/**
* Used to compare two members of a blob shape for equality. Array equals nesting
* inside of an Optional doesn't work
*
* Note: Generated code for equals method of Smithy shapes relies on this
*
* @param lhs The first to compare
* @param rhs The second to compare
* @return True if both are equal, false otherwise
*/
public static boolean blobTypeEquals(Optional lhs, Optional rhs) {
if (lhs.equals(rhs)) {
//both are same instance, both are same contained array, or both are empty
return true;
}
if (!lhs.isPresent() || !rhs.isPresent()) {
//if just one or the other is empty at this point
return false;
}
//now we know both are present so compare the arrays
return Arrays.equals(lhs.get(), rhs.get());
}
private static class Base64BlobSerializerDeserializer implements JsonSerializer, JsonDeserializer {
@Override
public byte[] deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
return StringUtils.base64Decode(json.getAsString().getBytes());
}
@Override
public JsonElement serialize(byte[] src, Type typeOfSrc, JsonSerializationContext context) {
return new JsonPrimitive(new String(StringUtils.base64Encode(src)));
}
}
private static class InstantSerializerDeserializer implements JsonSerializer, JsonDeserializer {
@Override
public Instant deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
double fSecondsEpoch = json.getAsDouble();
long secondsEpoch = (long)fSecondsEpoch;
long nanoEpoch = (long)((fSecondsEpoch - secondsEpoch) * 1_000_000_000.);
return Instant.ofEpochSecond(secondsEpoch, nanoEpoch);
}
@Override
public JsonElement serialize(Instant src, Type typeOfSrc, JsonSerializationContext context) {
return new JsonPrimitive((double)src.getEpochSecond() + (double)src.getNano() / 1000000000.);
}
}
/**
* For getting the actual service name
* @return The name of the service as a string
*/
public abstract String getServiceName();
private static final Map> FRAMEWORK_APPLICATION_MODEL_TYPES
= new HashMap<>();
static {
//TODO: find a reliable way to verify all of these are set? reflection cannot scan a package
FRAMEWORK_APPLICATION_MODEL_TYPES.put(AccessDeniedException.ERROR_CODE, AccessDeniedException.class);
FRAMEWORK_APPLICATION_MODEL_TYPES.put(UnsupportedOperationException.ERROR_CODE, UnsupportedOperationException.class);
FRAMEWORK_APPLICATION_MODEL_TYPES.put(ValidationException.ERROR_CODE, ValidationException.class);
}
/**
* Returns the application model class
* @param applicationModelType The application model
* @return The class of the given application model
*/
final public Optional> getApplicationModelClass(final String applicationModelType) {
final Class clazz = FRAMEWORK_APPLICATION_MODEL_TYPES.get(applicationModelType);
if (clazz != null) {
return Optional.of(clazz);
}
return getServiceClassType(applicationModelType);
}
/**
* Retreives all operations on the service
* @return All operations on the service
*/
public abstract Collection getAllOperations();
/**
* Need to override per specific service type so it can look up all associated types and errors
* possible.
*
* @param applicationModelType The application model
* @return The service class type of the given application model
*/
protected abstract Optional> getServiceClassType(String applicationModelType);
/**
* Retrieves the operation model context for a given operation name on the service
*
* This may not be a useful interface as generated code will typically pull a known operation model context
* Public visibility is useful for testing
*
* @param operationName The name of the operation
* @return The operation context associated with the given operation name
*/
public abstract OperationModelContext getOperationModelContext(String operationName);
public byte[] toJson(final EventStreamJsonMessage message) {
try {
final byte[] json = message.toPayload(getGson());
final String stringJson = new String(json, StandardCharsets.UTF_8);
//this feels like a hack. I'd prefer if java objects with no fields set serialized to being an empty object
//rather than "null"
if (null == stringJson || "null".equals(stringJson) || stringJson.isEmpty()) {
return "{}".getBytes(StandardCharsets.UTF_8);
}
return json;
} catch (Exception e) {
throw new SerializationException(message, e);
}
}
/**
* Converts the given EventStreamJsonMessage to a JSON string
* @param message The message to convert
* @return A JSON string
*/
public String toJsonString(final EventStreamJsonMessage message) {
return new String(toJson(message), StandardCharsets.UTF_8);
}
/**
* Internal getter method can be used by subclasses of specific service models to override default Gson
* @return Returns GSON context
*/
protected Gson getGson() {
return GSON;
}
/**
* In situations where the framework needs to do some JSON processing
* without a specific service/operation in context
*
* @return the static Gson instance capable of processing the basics of EventStreamableJsonMessage
*/
public static Gson getStaticGson() {
return GSON;
}
/**
* Creates a EventStreamJsonMessage from the given application model type string and payload.
* Uses this service's specific model class to create the EventStreamJsonMessage.
* @param applicationModelType The application model type string
* @param payload The payload
* @return A EventStreamMessage
*/
public EventStreamJsonMessage fromJson(final String applicationModelType, byte[] payload) {
final Optional> clazz = getApplicationModelClass(applicationModelType);
if (!clazz.isPresent()) {
throw new UnmappedDataException(applicationModelType);
}
return fromJson(clazz.get(), payload);
}
/**
* Creates a EventStreamJsonMessage of type T from the given application model
* class and payload.
* @param The type to convert the result to
* @param clazz The class
* @param payload The payload
* @return A EventStreamMessage of type T
*/
public T fromJson(final Class clazz, byte[] payload) {
try {
return getGson().fromJson(new String(payload, StandardCharsets.UTF_8), clazz);
} catch (Exception e) {
throw new DeserializationException(payload, e);
}
}
}
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