com.google.web.bindery.requestfactory.apt.TransportableTypeVisitor Maven / Gradle / Ivy
/*
* 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 java.util.Collection;
import java.util.List;
import java.util.Set;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.PrimitiveType;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.type.TypeVariable;
import javax.lang.model.type.WildcardType;
/**
* Scans a TypeMirror to determine if it can be transported by RequestFactory.
*/
class TransportableTypeVisitor extends TypeVisitorBase {
/**
* AutoBeans supports arbitrary parameterizations, but there's work that needs
* to be done on the Request serialization code to support arbitrarily-complex
* parameterizations. For the moment, we'll disallow anything other than a
* one-level parameterization.
*/
private boolean allowNestedParameterization = true;
@Override
public Boolean visitDeclared(DeclaredType t, State state) {
if (t.asElement().getKind().equals(ElementKind.ENUM)) {
return true;
}
if (state.types.isAssignable(t, state.entityProxyType)
|| state.types.isAssignable(t, state.valueProxyType)) {
TypeElement proxyElement = (TypeElement) t.asElement();
state.maybeScanProxy(proxyElement);
state.requireMapping(proxyElement);
return true;
}
if (state.types.isAssignable(t, state.entityProxyIdType)) {
DeclaredType asId = (DeclaredType) State.viewAs(state.entityProxyIdType, t, state);
if (asId.getTypeArguments().isEmpty()) {
return false;
}
return asId.getTypeArguments().get(0).accept(this, state);
}
for (DeclaredType valueType : getValueTypes(state)) {
if (state.types.isAssignable(t, valueType)) {
return true;
}
}
if (state.types.isAssignable(t, state.findType(List.class))
|| state.types.isAssignable(t, state.findType(Set.class))) {
if (!allowNestedParameterization) {
return false;
}
allowNestedParameterization = false;
DeclaredType asCollection =
(DeclaredType) State.viewAs(state.findType(Collection.class), t, state);
if (asCollection.getTypeArguments().isEmpty()) {
return false;
}
return t.getTypeArguments().get(0).accept(this, state);
}
return false;
}
@Override
public Boolean visitPrimitive(PrimitiveType x, State state) {
return true;
}
@Override
public Boolean visitTypeVariable(TypeVariable t, State state) {
if (t.equals(t.getUpperBound())) {
/*
* Weird case seen in Eclipse with self-parameterized type variables such
* as >.
*
* TODO(bobv): Should intersection types be allowed at all? They don't
* seem to make much sense in the most-derived interface types, since the
* RF Generator won't know how to implement them.
*/
return state.types.erasure(t).accept(this, state);
}
// Allow
return t.getUpperBound().accept(this, state);
}
@Override
public Boolean visitWildcard(WildcardType t, State state) {
// Allow List
return state.types.erasure(t).accept(this, state);
}
@Override
protected Boolean defaultAction(TypeMirror arg0, State arg1) {
return false;
}
}