/*
* Copyright 2011 Google 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.google.web.bindery.requestfactory.apt;
import com.google.web.bindery.requestfactory.apt.ClientToDomainMapper.UnmappedTypeException;
import com.google.web.bindery.requestfactory.shared.ProxyFor;
import com.google.web.bindery.requestfactory.shared.ProxyForName;
import com.google.web.bindery.requestfactory.shared.Service;
import com.google.web.bindery.requestfactory.shared.ServiceName;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.Name;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.ExecutableType;
import javax.lang.model.type.MirroredTypeException;
import javax.lang.model.type.TypeKind;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.ElementFilter;
/**
* Checks client to domain mappings.
*/
class DomainChecker extends ScannerBase<Void> {
/**
* Attempt to find the most specific method that conforms to a given
* signature.
*/
static class MethodFinder extends ScannerBase<ExecutableElement> {
private TypeElement domainType;
private ExecutableElement found;
private final boolean boxReturnType;
private final CharSequence name;
private final TypeMirror returnType;
private final List<TypeMirror> params;
public MethodFinder(CharSequence name, TypeMirror returnType, List<TypeMirror> params,
boolean boxReturnType, State state) {
this.boxReturnType = boxReturnType;
this.name = name;
this.returnType = TypeSimplifier.simplify(returnType, boxReturnType, state);
List<TypeMirror> temp = new ArrayList<TypeMirror>(params.size());
for (TypeMirror param : params) {
temp.add(TypeSimplifier.simplify(param, false, state));
}
this.params = Collections.unmodifiableList(temp);
}
@Override
public ExecutableElement visitExecutable(ExecutableElement domainMethodElement, State state) {
// Quick check for name, paramer count, and return type assignability
if (domainMethodElement.getSimpleName().contentEquals(name)
&& domainMethodElement.getParameters().size() == params.size()) {
// Pick up parameterizations in domain type
ExecutableType domainMethod = viewIn(domainType, domainMethodElement, state);
boolean returnTypeMatches;
if (returnType == null) {
/*
* This condition is for methods that we don't really care about the
* domain return types (for getId(), getVersion()).
*/
returnTypeMatches = true;
} else {
TypeMirror domainReturn =
TypeSimplifier.simplify(domainMethod.getReturnType(), boxReturnType, state);
// The isSameType handles the NONE case.
returnTypeMatches = state.types.isSubtype(domainReturn, returnType);
}
if (returnTypeMatches) {
boolean paramsMatch = true;
Iterator<TypeMirror> lookFor = params.iterator();
Iterator<? extends TypeMirror> domainParam = domainMethod.getParameterTypes().iterator();
while (lookFor.hasNext()) {
assert domainParam.hasNext();
TypeMirror requestedType = lookFor.next();
TypeMirror paramType = TypeSimplifier.simplify(domainParam.next(), false, state);
if (!state.types.isSubtype(requestedType, paramType)) {
paramsMatch = false;
}
}
if (paramsMatch) {
// Keep most-specific method signature
if (found == null
|| state.types.isSubsignature(domainMethod, (ExecutableType) found.asType())) {
found = domainMethodElement;
}
}
}
}
return found;
}
@Override
public ExecutableElement visitType(TypeElement domainType, State state) {
this.domainType = domainType;
return scanAllInheritedMethods(domainType, state);
}
}
/**
* This is used as the target for errors since generic methods show up as
* synthetic elements that don't correspond to any source.
*/
private TypeElement checkedElement;
private boolean currentTypeIsProxy;
private TypeElement domainElement;
private boolean requireInstanceDomainMethods;
private boolean requireStaticDomainMethods;
@Override
public Void visitExecutable(ExecutableElement clientMethodElement, State state) {
if (shouldIgnore(clientMethodElement, state)) {
return null;
}
// Ignore overrides of stableId() in proxies
Name name = clientMethodElement.getSimpleName();
if (currentTypeIsProxy && name.contentEquals("stableId")
&& clientMethodElement.getParameters().isEmpty()) {
return null;
}
ExecutableType clientMethod = viewIn(checkedElement, clientMethodElement, state);
List<TypeMirror> lookFor = new ArrayList<TypeMirror>();
// Convert client method signature to domain types
TypeMirror returnType;
try {
returnType = convertToDomainTypes(clientMethod, lookFor, clientMethodElement, state);
} catch (UnmappedTypeException e) {
/*
* Unusual: this would happen if a RequestContext for which we have a
* resolved domain service method uses unresolved proxy types. For
* example, the RequestContext uses a @Service annotation, while one or
* more proxy types use @ProxyForName("") and specify a domain type not
* available to the compiler.
*/
return null;
}
ExecutableElement domainMethod;
if (currentTypeIsProxy && isSetter(clientMethodElement, state)) {
// Look for void setFoo(...)
domainMethod =
new MethodFinder(name, state.types.getNoType(TypeKind.VOID), lookFor, false, state).scan(
domainElement, state);
if (domainMethod == null) {
// Try a builder style
domainMethod =
new MethodFinder(name, domainElement.asType(), lookFor, false, state).scan(
domainElement, state);
}
} else {
/*
* The usual case for getters and all service methods. Only box return
* types when matching context methods since there's a significant
* semantic difference between a null Integer and 0.
*/
domainMethod =
new MethodFinder(name, returnType, lookFor, !currentTypeIsProxy, state).scan(
domainElement, state);
}
if (domainMethod == null) {
// Did not find a service method
StringBuilder sb = new StringBuilder();
sb.append(returnType).append(" ").append(name).append("(");
for (TypeMirror param : lookFor) {
sb.append(param);
}
sb.append(")");
state.poison(clientMethodElement, Messages.domainMissingMethod(sb));
return null;
}
/*
* Check the domain method for any requirements for it to be static.
* InstanceRequests assume instance methods on the domain type.
*/
boolean isInstanceRequest =
state.types.isSubtype(clientMethod.getReturnType(), state.instanceRequestType);
if ((isInstanceRequest || requireInstanceDomainMethods)
&& domainMethod.getModifiers().contains(Modifier.STATIC)) {
state.poison(checkedElement, Messages.domainMethodWrongModifier(false, domainMethod
.getSimpleName()));
}
if (!isInstanceRequest && requireStaticDomainMethods
&& !domainMethod.getModifiers().contains(Modifier.STATIC)) {
state.poison(checkedElement, Messages.domainMethodWrongModifier(true, domainMethod
.getSimpleName()));
}
// Record the mapping
state.addMapping(clientMethodElement, domainMethod);
return null;
}
@Override
public Void visitType(TypeElement clientTypeElement, State state) {
TypeMirror clientType = clientTypeElement.asType();
checkedElement = clientTypeElement;
boolean isEntityProxy = state.types.isSubtype(clientType, state.entityProxyType);
currentTypeIsProxy = isEntityProxy || state.types.isSubtype(clientType, state.valueProxyType);
domainElement = (TypeElement) state.getClientToDomainMap().get(clientTypeElement);
if (domainElement == null) {
// A proxy with an unresolved domain type (e.g. ProxyForName(""))
return null;
}
requireInstanceDomainMethods = false;
requireStaticDomainMethods = false;
if (currentTypeIsProxy) {
// Require domain property methods to be instance methods
requireInstanceDomainMethods = true;
if (!hasProxyLocator(clientTypeElement, state)) {
// Domain types without a Locator should have a no-arg constructor
if (!hasNoArgConstructor(domainElement)) {
state.warn(clientTypeElement, Messages.domainNoDefaultConstructor(domainElement
.getSimpleName(), clientTypeElement.getSimpleName(), state.requestContextType
.asElement().getSimpleName()));
}
/*
* Check for getId(), getVersion(), and findFoo() for any type that
* extends EntityProxy, but not on EntityProxy itself, since EntityProxy
* is mapped to java.lang.Object.
*/
if (isEntityProxy && !state.types.isSameType(clientType, state.entityProxyType)) {
checkDomainEntityMethods(state);
}
}
} else if (!hasServiceLocator(clientTypeElement, state)) {
/*
* Otherwise, we're looking at a RequestContext. If it doesn't have a
* ServiceLocator, all methods must be static.
*/
requireStaticDomainMethods = true;
}
scanAllInheritedMethods(clientTypeElement, state);
return null;
}
/**
* Check that {@code getId()} and {@code getVersion()} exist and that they are
* non-static. Check that {@code findFoo()} exists, is static, returns an
* appropriate type, and its parameter is assignable from the return value
* from {@code getId()}.
*/
private void checkDomainEntityMethods(State state) {
ExecutableElement getId =
new MethodFinder("getId", null, Collections.<TypeMirror> emptyList(), false, state).scan(
domainElement, state);
if (getId == null) {
state.poison(checkedElement, Messages.domainNoGetId(domainElement.asType()));
} else {
if (getId.getModifiers().contains(Modifier.STATIC)) {
state.poison(checkedElement, Messages.domainGetIdStatic());
}
// Can only check findFoo() if we have a getId
ExecutableElement find =
new MethodFinder("find" + domainElement.getSimpleName(), domainElement.asType(),
Collections.singletonList(getId.getReturnType()), false, state).scan(domainElement,
state);
if (find == null) {
state.warn(checkedElement, Messages.domainMissingFind(domainElement.asType(), domainElement
.getSimpleName(), getId.getReturnType(), checkedElement.getSimpleName()));
} else if (!find.getModifiers().contains(Modifier.STATIC)) {
state.poison(checkedElement, Messages.domainFindNotStatic(domainElement.getSimpleName()));
}
}
ExecutableElement getVersion =
new MethodFinder("getVersion", null, Collections.<TypeMirror> emptyList(), false, state)
.scan(domainElement, state);
if (getVersion == null) {
state.poison(checkedElement, Messages.domainNoGetVersion(domainElement.asType()));
} else if (getVersion.getModifiers().contains(Modifier.STATIC)) {
state.poison(checkedElement, Messages.domainGetVersionStatic());
}
}
/**
* Converts a client method's types to their domain counterparts.
*
* @param clientMethod the RequestContext method to validate
* @param parameterAccumulator an out parameter that will be populated with
* the converted paramater types
* @param warnTo The element to which warnings should be posted if one or more
* client types cannot be converted to domain types for validation
* @param state the State object
* @throws UnmappedTypeException if one or more types used in
* {@code clientMethod} cannot be resolved to domain types
*/
private TypeMirror convertToDomainTypes(ExecutableType clientMethod,
List<TypeMirror> parameterAccumulator, ExecutableElement warnTo, State state)
throws UnmappedTypeException {
boolean error = false;
TypeMirror returnType;
try {
returnType = clientMethod.getReturnType().accept(new ClientToDomainMapper(), state);
} catch (UnmappedTypeException e) {
error = true;
returnType = null;
state.warn(warnTo, Messages.methodNoDomainPeer(e.getClientType(), false));
}
for (TypeMirror param : clientMethod.getParameterTypes()) {
try {
parameterAccumulator.add(param.accept(new ClientToDomainMapper(), state));
} catch (UnmappedTypeException e) {
parameterAccumulator.add(null);
error = true;
state.warn(warnTo, Messages.methodNoDomainPeer(e.getClientType(), true));
}
}
if (error) {
throw new UnmappedTypeException();
}
return returnType;
}
/**
* Looks for a no-arg constructor or no constructors at all. Instance
* initializers are ignored.
*/
private boolean hasNoArgConstructor(TypeElement x) {
List<ExecutableElement> constructors = ElementFilter.constructorsIn(x.getEnclosedElements());
if (constructors.isEmpty()) {
return true;
}
for (ExecutableElement constructor : constructors) {
if (constructor.getParameters().isEmpty()) {
return true;
}
}
return false;
}
private boolean hasProxyLocator(TypeElement x, State state) {
ProxyFor proxyFor = x.getAnnotation(ProxyFor.class);
if (proxyFor != null) {
// See javadoc on getAnnotation
try {
proxyFor.locator();
throw new RuntimeException("Should not reach here");
} catch (MirroredTypeException expected) {
TypeMirror locatorType = expected.getTypeMirror();
return !state.types.asElement(locatorType).equals(state.locatorType.asElement());
}
}
ProxyForName proxyForName = x.getAnnotation(ProxyForName.class);
return proxyForName != null && !proxyForName.locator().isEmpty();
}
private boolean hasServiceLocator(TypeElement x, State state) {
Service service = x.getAnnotation(Service.class);
if (service != null) {
// See javadoc on getAnnotation
try {
service.locator();
throw new RuntimeException("Should not reach here");
} catch (MirroredTypeException expected) {
TypeMirror locatorType = expected.getTypeMirror();
return !state.types.asElement(locatorType).equals(state.serviceLocatorType.asElement());
}
}
ServiceName serviceName = x.getAnnotation(ServiceName.class);
return serviceName != null && !serviceName.locator().isEmpty();
}
}