feign.ReflectiveFeign Maven / Gradle / Ivy
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/**
* Copyright 2012-2019 The Feign Authors
*
* 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 feign.template.UriUtils;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.*;
import java.util.Map.Entry;
import feign.InvocationHandlerFactory.MethodHandler;
import feign.Param.Expander;
import feign.Request.Options;
import feign.codec.Decoder;
import feign.codec.EncodeException;
import feign.codec.Encoder;
import feign.codec.ErrorDecoder;
import static feign.Util.checkArgument;
import static feign.Util.checkNotNull;
public class ReflectiveFeign extends Feign {
private final ParseHandlersByName targetToHandlersByName;
private final InvocationHandlerFactory factory;
private final QueryMapEncoder queryMapEncoder;
ReflectiveFeign(ParseHandlersByName targetToHandlersByName, InvocationHandlerFactory factory,
QueryMapEncoder queryMapEncoder) {
this.targetToHandlersByName = targetToHandlersByName;
this.factory = factory;
this.queryMapEncoder = queryMapEncoder;
}
/**
* 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 newInstance(Target target) {
Map nameToHandler = targetToHandlersByName.apply(target);
Map methodToHandler = new LinkedHashMap();
List defaultMethodHandlers = new LinkedList();
for (Method method : target.type().getMethods()) {
if (method.getDeclaringClass() == Object.class) {
continue;
} else if (Util.isDefault(method)) {
DefaultMethodHandler handler = new DefaultMethodHandler(method);
defaultMethodHandlers.add(handler);
methodToHandler.put(method, handler);
} else {
methodToHandler.put(method, nameToHandler.get(Feign.configKey(target.type(), method)));
}
}
InvocationHandler handler = factory.create(target, methodToHandler);
T proxy = (T) Proxy.newProxyInstance(target.type().getClassLoader(), new Class[]{target.type()}, handler);
for (DefaultMethodHandler defaultMethodHandler : defaultMethodHandlers) {
defaultMethodHandler.bindTo(proxy);
}
return proxy;
}
static class FeignInvocationHandler implements InvocationHandler {
private final Target target;
private final Map dispatch;
FeignInvocationHandler(Target target, Map dispatch) {
this.target = checkNotNull(target, "target");
this.dispatch = checkNotNull(dispatch, "dispatch for %s", target);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if ("equals".equals(method.getName())) {
try {
Object otherHandler = args.length > 0 && args[0] != null
? Proxy.getInvocationHandler(args[0])
: null;
return equals(otherHandler);
} catch (IllegalArgumentException e) {
return false;
}
} else if ("hashCode".equals(method.getName())) {
return hashCode();
} else if ("toString".equals(method.getName())) {
return toString();
}
return dispatch.get(method).invoke(args);
}
@Override
public boolean equals(Object obj) {
if (obj instanceof FeignInvocationHandler) {
FeignInvocationHandler other = (FeignInvocationHandler) obj;
return target.equals(other.target);
}
return false;
}
@Override
public int hashCode() {
return target.hashCode();
}
@Override
public String toString() {
return target.toString();
}
}
static final class ParseHandlersByName {
private final Contract contract;
private final Options options;
private final Encoder encoder;
private final Decoder decoder;
private final ErrorDecoder errorDecoder;
private final QueryMapEncoder queryMapEncoder;
private final SynchronousMethodHandler.Factory factory;
ParseHandlersByName(Contract contract, Options options, Encoder encoder, Decoder decoder,
QueryMapEncoder queryMapEncoder, ErrorDecoder errorDecoder, SynchronousMethodHandler.Factory factory) {
this.contract = contract;
this.options = options;
this.factory = factory;
this.errorDecoder = errorDecoder;
this.queryMapEncoder = queryMapEncoder;
this.encoder = checkNotNull(encoder, "encoder");
this.decoder = checkNotNull(decoder, "decoder");
}
public Map apply(Target key) {
List metadata = contract.parseAndValidatateMetadata(key.type());
Map result = new LinkedHashMap();
for (MethodMetadata md : metadata) {
BuildTemplateByResolvingArgs buildTemplate;
if (!md.formParams().isEmpty() && md.template().bodyTemplate() == null) {
buildTemplate = new BuildFormEncodedTemplateFromArgs(md, encoder, queryMapEncoder);
} else if (md.bodyIndex() != null) {
buildTemplate = new BuildEncodedTemplateFromArgs(md, encoder, queryMapEncoder);
} else {
buildTemplate = new BuildTemplateByResolvingArgs(md, queryMapEncoder);
}
result.put(md.configKey(), factory.create(key, md, buildTemplate, options, decoder, errorDecoder));
}
return result;
}
}
private static class BuildTemplateByResolvingArgs implements RequestTemplate.Factory {
private final QueryMapEncoder queryMapEncoder;
protected final MethodMetadata metadata;
private final Map indexToExpander = new LinkedHashMap();
private BuildTemplateByResolvingArgs(MethodMetadata metadata, QueryMapEncoder queryMapEncoder) {
this.metadata = metadata;
this.queryMapEncoder = queryMapEncoder;
if (metadata.indexToExpander() != null) {
indexToExpander.putAll(metadata.indexToExpander());
return;
}
if (metadata.indexToExpanderClass().isEmpty()) {
return;
}
for (Entry> indexToExpanderClass : metadata.indexToExpanderClass()
.entrySet()) {
try {
indexToExpander.put(indexToExpanderClass.getKey(), indexToExpanderClass.getValue().newInstance());
} catch (InstantiationException e) {
throw new IllegalStateException(e);
} catch (IllegalAccessException e) {
throw new IllegalStateException(e);
}
}
}
@Override
public RequestTemplate create(Object[] argv) {
RequestTemplate mutable = RequestTemplate.from(metadata.template());
if (metadata.urlIndex() != null) {
int urlIndex = metadata.urlIndex();
checkArgument(argv[urlIndex] != null, "URI parameter %s was null", urlIndex);
mutable.target(String.valueOf(argv[urlIndex]));
}
Map varBuilder = new LinkedHashMap();
for (Entry> entry : metadata.indexToName().entrySet()) {
int i = entry.getKey();
Object value = argv[entry.getKey()];
if (value != null) { // Null values are skipped.
Object expandValue = value;
for (String name : entry.getValue()) {
if (indexToExpander.containsKey(i)) {
expandValue = expandElementsWithName(indexToExpander.get(i), value, name);
}
varBuilder.put(name, expandValue);
}
}
}
RequestTemplate template = resolve(argv, mutable, varBuilder);
if (metadata.queryMapIndex() != null) {
// add query map parameters after initial resolve so that they take
// precedence over any predefined values
Object value = argv[metadata.queryMapIndex()];
Map queryMap = toQueryMap(value);
template = addQueryMapQueryParameters(queryMap, template);
}
if (metadata.headerMapIndex() != null) {
template = addHeaderMapHeaders((Map) argv[metadata.headerMapIndex()], template);
}
return template;
}
private Map toQueryMap(Object value) {
if (value instanceof Map) {
return (Map) value;
}
try {
return queryMapEncoder.encode(value);
} catch (EncodeException e) {
throw new IllegalStateException(e);
}
}
private Object expandElements(Expander expander, Object value) {
if (value instanceof Iterable) {
return expandIterable(expander, (Iterable) value);
}
return expander.expand(value);
}
private Object expandElementsWithName(Expander expander, Object value, String name) {
if (value instanceof Iterable) {
return expandIterable(expander, (Iterable) value);
}
return expander.expandWithName(value, name);
}
private List expandIterable(Expander expander, Iterable value) {
List values = new ArrayList();
for (Object element : value) {
if (element != null) {
values.add(expander.expand(element));
}
}
return values;
}
@SuppressWarnings("unchecked")
private RequestTemplate addHeaderMapHeaders(Map headerMap, RequestTemplate mutable) {
for (Entry currEntry : headerMap.entrySet()) {
Collection values = new ArrayList();
Object currValue = currEntry.getValue();
if (currValue instanceof Iterable) {
Iterator iter = ((Iterable) currValue).iterator();
while (iter.hasNext()) {
Object nextObject = iter.next();
values.add(nextObject == null ? null : nextObject.toString());
}
} else {
values.add(currValue == null ? null : currValue.toString());
}
mutable.header(currEntry.getKey(), values);
}
return mutable;
}
@SuppressWarnings("unchecked")
private RequestTemplate addQueryMapQueryParameters(Map queryMap, RequestTemplate mutable) {
for (Entry currEntry : queryMap.entrySet()) {
Collection values = new ArrayList();
boolean encoded = metadata.queryMapEncoded();
Object currValue = currEntry.getValue();
if (currValue instanceof Iterable) {
Iterator iter = ((Iterable) currValue).iterator();
while (iter.hasNext()) {
Object nextObject = iter.next();
values.add(nextObject == null
? null
: encoded ? nextObject.toString() : UriUtils.encode(nextObject.toString()));
}
} else {
values.add(currValue == null
? null
: encoded ? currValue.toString() : UriUtils.encode(currValue.toString()));
}
mutable.query(encoded ? currEntry.getKey() : UriUtils.encode(currEntry.getKey()), values);
}
return mutable;
}
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map variables) {
return mutable.resolve(variables);
}
}
private static class BuildFormEncodedTemplateFromArgs extends BuildTemplateByResolvingArgs {
private final Encoder encoder;
private BuildFormEncodedTemplateFromArgs(MethodMetadata metadata, Encoder encoder,
QueryMapEncoder queryMapEncoder) {
super(metadata, queryMapEncoder);
this.encoder = encoder;
}
@Override
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map variables) {
Map formVariables = new LinkedHashMap();
for (Entry entry : variables.entrySet()) {
if (metadata.formParams().contains(entry.getKey())) {
formVariables.put(entry.getKey(), entry.getValue());
}
}
try {
encoder.encode(formVariables, Encoder.MAP_STRING_WILDCARD, mutable);
} 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 encoder;
private BuildEncodedTemplateFromArgs(MethodMetadata metadata, Encoder encoder,
QueryMapEncoder queryMapEncoder) {
super(metadata, queryMapEncoder);
this.encoder = encoder;
}
@Override
protected RequestTemplate resolve(Object[] argv, RequestTemplate mutable, Map variables) {
Object body = argv[metadata.bodyIndex()];
checkArgument(body != null, "Body parameter %s was null", metadata.bodyIndex());
try {
encoder.encode(body, metadata.bodyType(), mutable);
} catch (EncodeException e) {
throw e;
} catch (RuntimeException e) {
throw new EncodeException(e.getMessage(), e);
}
return super.resolve(argv, mutable, variables);
}
}
}