/*
* Copyright (C) 2012 Facebook, 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.facebook.swift.codec.internal.reflection;
import com.facebook.swift.codec.ThriftCodec;
import com.facebook.swift.codec.ThriftCodecManager;
import com.facebook.swift.codec.internal.TProtocolReader;
import com.facebook.swift.codec.internal.TProtocolWriter;
import com.facebook.swift.codec.metadata.FieldKind;
import com.facebook.swift.codec.metadata.ThriftConstructorInjection;
import com.facebook.swift.codec.metadata.ThriftFieldInjection;
import com.facebook.swift.codec.metadata.ThriftFieldMetadata;
import com.facebook.swift.codec.metadata.ThriftInjection;
import com.facebook.swift.codec.metadata.ThriftMethodInjection;
import com.facebook.swift.codec.metadata.ThriftStructMetadata;
import com.google.common.base.Throwables;
import com.google.common.collect.Maps;
import org.apache.thrift.protocol.TProtocol;
import javax.annotation.concurrent.Immutable;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import static com.facebook.swift.codec.metadata.FieldKind.THRIFT_FIELD;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.Iterables.getOnlyElement;
import static java.lang.String.format;
@Immutable
public class ReflectionThriftUnionCodec<T> extends AbstractReflectionThriftCodec<T>
{
private final Map<Short, ThriftFieldMetadata> metadataMap;
private final Map.Entry<ThriftFieldMetadata, ThriftCodec<?>> idField;
public ReflectionThriftUnionCodec(ThriftCodecManager manager, ThriftStructMetadata metadata)
{
super(manager, metadata);
ThriftFieldMetadata idField = getOnlyElement(metadata.getFields(FieldKind.THRIFT_UNION_ID));
this.idField = Maps.<ThriftFieldMetadata, ThriftCodec<?>>immutableEntry(idField, manager.getCodec(idField.getThriftType()));
checkNotNull(this.idField.getValue(), "No codec for id field %s found", idField);
this.metadataMap = Maps.uniqueIndex(metadata.getFields(), ThriftFieldMetadata.getIdGetter());
}
@Override
public T read(TProtocol protocol)
throws Exception
{
TProtocolReader reader = new TProtocolReader(protocol);
reader.readStructBegin();
Map.Entry<Short, Object> data = null;
Short fieldId = null;
while (reader.nextField()) {
checkState(fieldId == null, "Received Union with more than one value (seen id %s, now id %s)", fieldId, reader.getFieldId());
fieldId = reader.getFieldId();
// do we have a codec for this field
ThriftCodec<?> codec = fields.get(fieldId);
if (codec == null) {
reader.skipFieldData();
}
else {
// is this field readable
ThriftFieldMetadata field = metadata.getField(fieldId);
if (field.isWriteOnly() || field.getType() != THRIFT_FIELD) {
reader.skipFieldData();
continue;
}
// read the value
Object value = reader.readField(codec);
if (value == null) {
continue;
}
data = Maps.immutableEntry(fieldId, value);
}
}
reader.readStructEnd();
// build the struct
return constructStruct(data);
}
@Override
public void write(T instance, TProtocol protocol)
throws Exception
{
TProtocolWriter writer = new TProtocolWriter(protocol);
Short idValue = (Short) getFieldValue(instance, idField.getKey());
writer.writeStructBegin(metadata.getStructName());
if (metadataMap.containsKey(idValue)) {
ThriftFieldMetadata fieldMetadata = metadataMap.get(idValue);
if (fieldMetadata.isReadOnly() || fieldMetadata.getType() != THRIFT_FIELD) {
throw new IllegalStateException(format("Field %s is not readable", fieldMetadata.getName()));
}
Object fieldValue = getFieldValue(instance, fieldMetadata);
// write the field
if (fieldValue != null) {
@SuppressWarnings("unchecked")
ThriftCodec<Object> codec = (ThriftCodec<Object>) fields.get(fieldMetadata.getId());
writer.writeField(fieldMetadata.getName(), fieldMetadata.getId(), codec, fieldValue);
}
}
writer.writeStructEnd();
}
@SuppressWarnings("unchecked")
private T constructStruct(Map.Entry<Short, Object> data)
throws Exception
{
// construct instance
Object instance = null;
ThriftFieldMetadata fieldMetadata = null;
if (data != null) {
fieldMetadata = metadataMap.get(data.getKey());
if (fieldMetadata != null && fieldMetadata.getConstructorInjection().isPresent()) {
ThriftConstructorInjection constructor = fieldMetadata.getConstructorInjection().get();
Object[] parametersValues = new Object[] { data.getValue() };
try {
instance = constructor.getConstructor().newInstance(parametersValues);
}
catch (InvocationTargetException e) {
if (e.getTargetException() != null) {
Throwables.propagateIfInstanceOf(e.getTargetException(), Exception.class);
}
throw e;
}
}
}
if (instance == null && metadata.getConstructorInjection().isPresent()) {
ThriftConstructorInjection constructor = metadata.getConstructorInjection().get();
// must be no-args
Object[] parametersValues = new Object[0];
try {
instance = constructor.getConstructor().newInstance(parametersValues);
}
catch (InvocationTargetException e) {
if (e.getTargetException() != null) {
Throwables.propagateIfInstanceOf(e.getTargetException(), Exception.class);
}
throw e;
}
}
if (fieldMetadata != null) {
// inject fields
for (ThriftInjection injection : fieldMetadata.getInjections()) {
if (injection instanceof ThriftFieldInjection) {
ThriftFieldInjection fieldInjection = (ThriftFieldInjection) injection;
if (data.getValue() != null) {
fieldInjection.getField().set(instance, data.getValue());
}
}
}
if (fieldMetadata.getMethodInjection().isPresent()) {
Object[] parametersValues = new Object[] { data.getValue() };
if (data.getValue() != null) {
try {
fieldMetadata.getMethodInjection().get().getMethod().invoke(instance, parametersValues);
}
catch (InvocationTargetException e) {
if (e.getTargetException() != null) {
Throwables.propagateIfInstanceOf(e.getTargetException(), Exception.class);
}
throw e;
}
}
}
}
if (data != null) {
// inject id value
for (ThriftInjection injection : idField.getKey().getInjections()) {
if (injection instanceof ThriftFieldInjection) {
ThriftFieldInjection fieldInjection = (ThriftFieldInjection) injection;
fieldInjection.getField().set(instance, data.getKey());
}
}
// builder method
if (metadata.getBuilderMethod().isPresent()) {
ThriftMethodInjection builderMethod = metadata.getBuilderMethod().get();
Object[] parametersValues = new Object[] { data.getValue() };
try {
instance = builderMethod.getMethod().invoke(instance, parametersValues);
checkState(instance != null, "Builder method returned a null instance");
checkState(metadata.getStructClass().isInstance(instance),
"Builder method returned instance of type %s, but an instance of %s is required",
instance.getClass().getName(),
metadata.getStructClass().getName());
}
catch (InvocationTargetException e) {
if (e.getTargetException() != null) {
Throwables.propagateIfInstanceOf(e.getTargetException(), Exception.class);
}
throw e;
}
}
}
return (T) instance;
}
}