/*
* Copyright 2000-2017 JetBrains s.r.o.
*
* 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.jetbrains.plugins.groovy.lang.typing;
import com.intellij.openapi.util.ClassExtension;
import com.intellij.psi.PsiType;
import org.jetbrains.annotations.ApiStatus.Experimental;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrExpression;
/**
* This API provides ability to plug into expression type calculation in Groovy.
* Each expression has its default implementation which is executed last.
* <p>
* The API is experimental at least until 2017.3.
*
* @param <T> expression class
* @see DefaultListOrMapTypeCalculator
* @see DefaultIndexAccessTypeCalculator
*/
@Experimental
public interface GrTypeCalculator<T extends GrExpression> {
ClassExtension<GrTypeCalculator> EP = new ClassExtension<>("org.intellij.groovy.typeCalculator");
/**
* @return {@code expression} type if some implementation can calculate it, otherwise {@code null}. <br/>
* The result type is the first non-{@code null} value returned.
*/
@Nullable
static PsiType getTypeFromCalculators(@NotNull GrExpression expression) {
for (GrTypeCalculator calculator : EP.forKey(expression.getClass())) {
//noinspection unchecked
PsiType type = calculator.getType(expression);
if (type != null) return type;
}
return null;
}
/**
* @return {@code null} if expression type cannot be calculated.
*/
@Nullable
PsiType getType(@NotNull T expression);
}