/*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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 org.inferred.freebuilder.processor.util;
import static com.google.common.collect.Iterables.any;
import com.google.common.base.Predicate;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.lang.model.element.TypeParameterElement;
import javax.lang.model.type.ArrayType;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.ErrorType;
import javax.lang.model.type.ExecutableType;
import javax.lang.model.type.NoType;
import javax.lang.model.type.NullType;
import javax.lang.model.type.PrimitiveType;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.type.TypeVariable;
import javax.lang.model.type.WildcardType;
import javax.lang.model.util.AbstractTypeVisitor6;
/** A type visitor that returns true if the type will be invalid if we write it out. */
public class IsInvalidTypeVisitor
extends AbstractTypeVisitor6<Boolean, Void> implements Predicate<TypeMirror> {
/** Handles self-referential types like {@code Comparable<E extends Comparable<E>>}. */
private final Map<DeclaredType, Boolean> invalidity = new LinkedHashMap<DeclaredType, Boolean>();
/** Returns true if input is neither null nor invalid. */
@Override
public boolean apply(TypeMirror input) {
return input != null && input.accept(this, null);
}
@Override
public Boolean visitPrimitive(PrimitiveType t, Void p) {
return false;
}
@Override
public Boolean visitNull(NullType t, Void p) {
return false;
}
@Override
public Boolean visitArray(ArrayType t, Void p) {
return apply(t.getComponentType());
}
@Override
public Boolean visitDeclared(DeclaredType t, Void p) {
if (invalidity.containsKey(t)) {
return invalidity.get(t);
}
invalidity.put(t, false);
boolean isInvalid = any(t.getTypeArguments(), this);
invalidity.put(t, isInvalid);
return isInvalid;
}
@Override
public Boolean visitError(ErrorType t, Void p) {
return true;
}
@Override
public Boolean visitTypeVariable(TypeVariable t, Void p) {
TypeParameterElement element = (TypeParameterElement) t.asElement();
return any(element.getBounds(), this);
}
@Override
public Boolean visitWildcard(WildcardType t, Void p) {
return apply(t.getExtendsBound()) || apply(t.getSuperBound());
}
@Override
public Boolean visitExecutable(ExecutableType t, Void p) {
return any(t.getParameterTypes(), this)
|| apply(t.getReturnType())
|| any(t.getThrownTypes(), this)
|| any(t.getTypeVariables(), this);
}
@Override
public Boolean visitNoType(NoType t, Void p) {
return false;
}
}