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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 feign;
import dagger.Lazy;
import dagger.Provides;
import feign.Request.Options;
import feign.codec.Decoder;
import feign.codec.EncodeException;
import feign.codec.Encoder;
import feign.codec.ErrorDecoder;
import feign.codec.IncrementalDecoder;
import feign.codec.StringDecoder;
import feign.codec.StringIncrementalDecoder;
import javax.inject.Inject;
import javax.inject.Named;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.Executor;
import static feign.Util.checkArgument;
import static feign.Util.checkNotNull;
import static feign.Util.checkState;
import static feign.Util.resolveLastTypeParameter;
import static java.lang.String.format;
@SuppressWarnings("rawtypes")
public class ReflectiveFeign extends Feign {
private final ParseHandlersByName targetToHandlersByName;
@Inject ReflectiveFeign(@Named("http") Lazy<Executor> httpExecutor, ParseHandlersByName targetToHandlersByName) {
super(httpExecutor);
this.targetToHandlersByName = targetToHandlersByName;
}
/**
* creates an api binding to the {@code target}. As this invokes reflection,
* care should be taken to cache the result.
*/
@SuppressWarnings("unchecked") @Override public <T> T newInstance(Target<T> target) {
Map<String, MethodHandler> nameToHandler = targetToHandlersByName.apply(target);
Map<Method, MethodHandler> methodToHandler = new LinkedHashMap<Method, MethodHandler>();
for (Method method : target.type().getDeclaredMethods()) {
if (method.getDeclaringClass() == Object.class)
continue;
methodToHandler.put(method, nameToHandler.get(Feign.configKey(method)));
}
FeignInvocationHandler handler = new FeignInvocationHandler(target, methodToHandler);
return (T) Proxy.newProxyInstance(target.type().getClassLoader(), new Class<?>[]{target.type()}, handler);
}
static class FeignInvocationHandler implements InvocationHandler {
private final Target target;
private final Map<Method, MethodHandler> methodToHandler;
FeignInvocationHandler(Target target, Map<Method, MethodHandler> methodToHandler) {
this.target = checkNotNull(target, "target");
this.methodToHandler = checkNotNull(methodToHandler, "methodToHandler for %s", target);
}
@Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
return methodToHandler.get(method).invoke(args);
}
@Override public int hashCode() {
return target.hashCode();
}
@Override public boolean equals(Object obj) {
if (this == obj)
return true;
if (FeignInvocationHandler.class != obj.getClass())
return false;
FeignInvocationHandler that = FeignInvocationHandler.class.cast(obj);
return this.target.equals(that.target);
}
@Override public String toString() {
return "target(" + target + ")";
}
}
@dagger.Module(complete = false, injects = Feign.class, library = true)
public static class Module {
@Provides Feign provideFeign(ReflectiveFeign in) {
return in;
}
}
private static IllegalStateException noConfig(String configKey, Class<?> type) {
return new IllegalStateException(format("no configuration for %s present for %s!", configKey,
type.getSimpleName()));
}
static final class ParseHandlersByName {
private final Contract contract;
private final Options options;
private final Map<Type, Encoder.Text<? super Object>> encoders = new HashMap<Type, Encoder.Text
F0C6
<? super Object>>();
private final Encoder.Text<Map<String, ?>> formEncoder;
private final Map<Type, Decoder.TextStream<?>> decoders = new HashMap<Type, Decoder.TextStream<?>>();
private final Map<Type, IncrementalDecoder.TextStream<?>> incrementalDecoders =
new HashMap<Type, IncrementalDecoder.TextStream<?>>();
private final ErrorDecoder errorDecoder;
private final MethodHandler.Factory factory;
@SuppressWarnings("unchecked")
@Inject ParseHandlersByName(Contract contract, Options options, Set<Encoder> encoders, Set<Decoder> decoders,
Set<IncrementalDecoder> incrementalDecoders, ErrorDecoder errorDecoder,
MethodHandler.Factory factory) {
this.contract = contract;
this.options = options;
this.factory = factory;
this.errorDecoder = errorDecoder;
for (Encoder encoder : encoders) {
checkState(encoder instanceof Encoder.Text,
"Currently, only Encoder.Text is supported. Found: ", encoder);
Type type = resolveLastTypeParameter(encoder.getClass(), Encoder.class);
this.encoders.put(type, Encoder.Text.class.cast(encoder));
}
try {
Type formEncoderType = getClass().getDeclaredField("formEncoder").getGenericType();
Type formType = resolveLastTypeParameter(formEncoderType, Encoder.class);
Encoder.Text<? super Object> formEncoder = this.encoders.get(formType);
if (formEncoder == null) {
formEncoder = this.encoders.get(Object.class);
}
this.formEncoder = (Encoder.Text) formEncoder;
} catch (NoSuchFieldException e) {
throw new AssertionError(e);
}
StringDecoder stringDecoder = new StringDecoder();
this.decoders.put(void.class, stringDecoder);
this.decoders.put(Response.class, stringDecoder);
this.decoders.put(String.class, stringDecoder);
for (Decoder decoder : decoders) {
checkState(decoder instanceof Decoder.TextStream,
"Currently, only Decoder.TextStream is supported. Found: ", decoder);
Type type = resolveLastTypeParameter(decoder.getClass(), Decoder.class);
this.decoders.put(type, Decoder.TextStream.class.cast(decoder));
}
StringIncrementalDecoder stringIncrementalDecoder = new StringIncrementalDecoder();
this.incrementalDecoders.put(Void.class, stringIncrementalDecoder);
this.incrementalDecoders.put(Response.class, stringIncrementalDecoder);
this.incrementalDecoders.put(String.class, stringIncrementalDecoder);
for (IncrementalDecoder incrementalDecoder : incrementalDecoders) {
checkState(incrementalDecoder instanceof IncrementalDecoder.TextStream,
"Currently, only IncrementalDecoder.TextStream is supported. Found: ", incrementalDecoder);
Type type = resolveLastTypeParameter(incrementalDecoder.getClass(), IncrementalDecoder.class);
this.incrementalDecoders.put(type, IncrementalDecoder.TextStream.class.cast(incrementalDecoder));
}
}
public Map<String, MethodHandler> apply(Target key) {
List<MethodMetadata> metadata = contract.parseAndValidatateMetadata(key.type());
Map<String, MethodHandler> result = new LinkedHashMap<String, MethodHandler>();
for (MethodMetadata md : metadata) {
BuildTemplateByResolvingArgs buildTemplate;
if (!md.formParams().isEmpty() && md.template().bodyTemplate() == null) {
if (formEncoder == null) {
throw new IllegalStateException(format("%s needs @Provides(type = Set) Encoder encoder()" +
"{ // Encoder.Text<Map<String, ?>> or Encoder.Text<Object>}", md.configKey()));
}
buildTemplate = new BuildFormEncodedTemplateFromArgs(md, formEncoder);
} else if (md.bodyIndex() != null) {
Encoder.Text<? super Object> encoder = encoders.get(md.bodyType());
if (encoder == null) {
encoder = encoders.get(Object.class);
}
if (encoder == null) {
throw new IllegalStateException(format("%s needs @Provides(type = Set) Encoder encoder()" +
"{ // Encoder.Text<%s> or Encoder.Text<Object>}", md.bodyType(), md.decodeInto()));
}
buildTemplate = new BuildEncodedTemplateFromArgs(md, encoder);
} else {
buildTemplate = new BuildTemplateByResolvingArgs(md);
}
if (md.incrementalCallbackIndex() != null) {
IncrementalDecoder.TextStream incrementalDecoder = incrementalDecoders.get(md.decodeInto());
if (incrementalDecoder == null) {
incrementalDecoder = incrementalDecoders.get(Object.class);
}
if (incrementalDecoder == null) {
throw new IllegalStateException(format("%s needs @Provides(type = Set) IncrementalDecoder incrementalDecoder()" +
"{ // IncrementalDecoder.TextStream<%s> or IncrementalDecoder.TextStream<Object>}", md.configKey(), md.decodeInto()));
}
result.put(md.configKey(), factory.create(key, md, buildTemplate, options, incrementalDecoder, errorDecoder));
} else {
Decoder.TextStream decoder = decoders.get(md.decodeInto());
if (decoder == null) {
decoder = decoders.get(Object.class);
}
if (decoder == null) {
throw new IllegalStateException(format("%s needs @Provides(type = Set) Decoder decoder()" +
"{ // Decoder.TextStream<%s> or Decoder.TextStream<Object>}", md.configKey(), md.decodeInto()));
}
result.put(md.configKey(), factory.create(key, md, buildTemplate, options, decoder, errorDecoder));
}
}
return result;
}
}
private static class BuildTemplateByResolvingArgs implements MethodHandler.BuildTemplateFromArgs {
protected final MethodMetadata metadata;
private BuildTemplateByResolvingArgs(MethodMetadata metadata) {
this.metadata = metadata;
}
public RequestTemplate apply(Object[] argv) {
RequestTemplate mutable = new RequestTemplate(metadata.template());
if (metadata.urlIndex() != null) {
int urlIndex = metadata.urlIndex();
checkArgument(argv[urlIndex] != null, "URI parameter %s was null", urlIndex);
mutable.insert(0, String.valueOf(argv[urlIndex]));
}
Map<String, Object> varBuilder = new LinkedHashMap<String, Object>();
for (Entry<Integer, Collection<String>> entry : metadata.indexToName().entrySet()) {
Object value = argv[entry.getKey()];
if (value != null) { // Null values are skipped.
for (String name : entry.getValue())
varBuilder.put(name, value);
}
}
return resolve(argv, mutable, varBuilder);
}
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map<String, Object> variables) {
return mutable.resolve(variables);
}
}
private static class BuildFormEncodedTemplateFromArgs extends BuildTemplateByResolvingArgs {
private final Encoder.Text<Map<String, ?>> formEncoder;
private BuildFormEncodedTemplateFromArgs(MethodMetadata metadata, Encoder.Text<Map<String, ?>> formEncoder) {
super(metadata);
this.formEncoder = formEncoder;
}
@Override
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map<String, Object> variables) {
Map<String, Object> formVariables = new LinkedHashMap<String, Object>();
for (Entry<String, Object> entry : variables.entrySet()) {
if (metadata.formParams().contains(entry.getKey()))
formVariables.put(entry.getKey(), entry.getValue());
}
try {
mutable.body(formEncoder.encode(formVariables));
} catch (EncodeException e) {
throw e;
} catch (RuntimeException e) {
throw new EncodeException(e.getMessage(), e);
}
return super.resolve(argv, mutable, variables);
}
}
private static class BuildEncodedTemplateFromArgs extends BuildTemplateByResolvingArgs {
private final Encoder.Text<? super Object> encoder;
private BuildEncodedTemplateFromArgs(MethodMetadata metadata, Encoder.Text<? super Object> encoder) {
super(metadata);
this.encoder = encoder;
}
@Override
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map<String, Object> variables) {
Object body = argv[metadata.bodyIndex()];
checkArgument(body != null, "Body parameter %s was null", metadata.bodyIndex());
try {
mutable.body(encoder.encode(body));
} catch (EncodeException e) {
throw e;
} catch (RuntimeException e) {
throw new EncodeException(e.getMessage(), e);
}
return super.resolve(argv, mutable, variables);
}
}
}