/*
* Copyright (c) 2013, the Dart project authors.
*
* Licensed under the Eclipse Public License v1.0 (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.eclipse.org/legal/epl-v10.html
*
* 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.dart.engine.internal.element.member;
import com.google.dart.engine.element.ClassElement;
import com.google.dart.engine.element.ElementVisitor;
import com.google.dart.engine.element.FieldElement;
import com.google.dart.engine.element.PropertyAccessorElement;
import com.google.dart.engine.type.InterfaceType;
import com.google.dart.engine.type.Type;
/**
* Instances of the class {@code FieldMember} represent a field element defined in a parameterized
* type where the values of the type parameters are known.
*/
public class FieldMember extends VariableMember implements FieldElement {
/**
* If the given field's type is different when any type parameters from the defining type's
* declaration are replaced with the actual type arguments from the defining type, create a field
* member representing the given field. Return the member that was created, or the base field if
* no member was created.
*
* @param baseField the base field for which a member might be created
* @param definingType the type defining the parameters and arguments to be used in the
* substitution
* @return the field element that will return the correctly substituted types
*/
public static FieldElement from(FieldElement baseField, InterfaceType definingType) {
if (!isChangedByTypeSubstitution(baseField, definingType)) {
return baseField;
}
// TODO(brianwilkerson) Consider caching the substituted type in the instance. It would use more
// memory but speed up some operations. We need to see how often the type is being re-computed.
return new FieldMember(baseField, definingType);
}
/**
* Determine whether the given field's type is changed when type parameters from the defining
* type's declaration are replaced with the actual type arguments from the defining type.
*
* @param baseField the base field
* @param definingType the type defining the parameters and arguments to be used in the
* substitution
* @return true if the type is changed by type substitution.
*/
private static boolean isChangedByTypeSubstitution(FieldElement baseField,
InterfaceType definingType) {
Type[] argumentTypes = definingType.getTypeArguments();
if (baseField != null && argumentTypes.length != 0) {
Type baseType = baseField.getType();
Type[] parameterTypes = definingType.getElement().getType().getTypeArguments();
if (baseType != null) {
Type substitutedType = baseType.substitute(argumentTypes, parameterTypes);
if (!baseType.equals(substitutedType)) {
return true;
}
}
// If the field has a propagated type, then we need to check whether the propagated type
// needs substitution.
Type basePropagatedType = baseField.getPropagatedType();
if (basePropagatedType != null) {
Type substitutedPropagatedType = basePropagatedType.substitute(
argumentTypes,
parameterTypes);
if (!basePropagatedType.equals(substitutedPropagatedType)) {
return true;
}
}
}
return false;
}
/**
* Initialize a newly created element to represent a field of the given parameterized type.
*
* @param baseElement the element on which the parameterized element was created
* @param definingType the type in which the element is defined
*/
public FieldMember(FieldElement baseElement, InterfaceType definingType) {
super(baseElement, definingType);
}
@Override
public <R> R accept(ElementVisitor<R> visitor) {
return visitor.visitFieldElement(this);
}
@Override
public FieldElement getBaseElement() {
return (FieldElement) super.getBaseElement();
}
@Override
public ClassElement getEnclosingElement() {
return getBaseElement().getEnclosingElement();
}
@Override
public PropertyAccessorElement getGetter() {
return PropertyAccessorMember.from(getBaseElement().getGetter(), getDefiningType());
}
@Override
public Type getPropagatedType() {
return substituteFor(getBaseElement().getPropagatedType());
}
@Override
public PropertyAccessorElement getSetter() {
return PropertyAccessorMember.from(getBaseElement().getSetter(), getDefiningType());
}
@Override
public boolean isStatic() {
return getBaseElement().isStatic();
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(getType());
builder.append(" ");
builder.append(getDisplayName());
return builder.toString();
}
@Override
protected InterfaceType getDefiningType() {
return (InterfaceType) super.getDefiningType();
}
}