/*
* Copyright 2015 Lukas Krejci
*
* 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.revapi.java.spi;
import java.util.EnumSet;
import java.util.List;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import org.revapi.Difference;
import org.revapi.configuration.Configurable;
/**
* An interface that java API checkers need to implement.
*
* <p>The methods on this interface are called in the following order:
* <pre><code>
* initialize
* setOldTypeEnvironment
* setNewTypeEnvironment
* (visitClass
* (visitClass ... visitEnd)* //inner classes
* (visitField
* visitAnnotation*
* visitEnd)*
* (visitMethod
* (visitMethodParameter
* visitAnnotation*
* visitEnd)*
* visitAnnotation*
* visitEnd)*
* visitAnnotation*
* visitEnd)*
* </code></pre>
*
* <p>Consider inheriting from the {@link org.revapi.java.spi.CheckBase} instead of directly implementing this
* interface because it takes care of matching the corresponding {@code visit*()} and {@code visitEnd()} calls.
*
* @author Lukas Krejci
* @since 0.1
*/
public interface Check extends Configurable {
/**
* The environment containing the old version of the classes. This can be used to reason about the
* classes when doing the checks.
*
* <p>Called once after the check has been instantiated.
*
* @param env the environment to obtain the helper objects using which one can navigate and examine types
*/
void setOldTypeEnvironment(@Nonnull TypeEnvironment env);
/**
* The environment containing the new version of the classes. This can be used to reason about the
* classes when doing the checks.
*
* <p>Called once after the check has been instantiated.
*
* @param env the environment to obtain the helper objects using which one can navigate and examine types
*/
void setNewTypeEnvironment(@Nonnull TypeEnvironment env);
/**
* Each check typically checks only a single type of java element - a method or an annotation - but may be
* interested in more.
*
* <p>This method must be used by the implementations to advertise what type of checks they are interested in.
* Only the appropriate {@code visit*} calls will then be made on the check instances.
*
* @return the set of check types this instance is interested in performing
*/
EnumSet<Type> getInterest();
/**
* Each of the other visit* calls is followed by a corresponding call to this method in a stack-like
* manner.
*
* <p>I.e. a series of calls might look like this:<br>
* <pre><code>
* visitClass();
* visitMethod();
* visitEnd();
* visitMethod();
* visitEnd();
* visitEnd(); //"ends" the visitClass()
* </code></pre>
*
* @return the list of found differences between corresponding elements or null if no differences found (null is
* considered equivalent to returning an empty collection).
*/
@Nullable
List<Difference> visitEnd();
void visitClass(@Nullable JavaTypeElement oldType, @Nullable JavaTypeElement newType);
void visitMethod(@Nullable JavaMethodElement oldMethod, @Nullable JavaMethodElement newMethod);
void visitMethodParameter(@Nullable JavaMethodParameterElement oldParameter, @Nullable JavaMethodParameterElement newParameter);
void visitField(@Nullable JavaFieldElement oldField, @Nullable JavaFieldElement newField);
/**
* Visiting annotation is slightly different, because it is not followed by the standard {@link #visitEnd()} call.
* Instead, because visiting annotation is always "terminal" in a sense that an annotation doesn't have any child
* elements, the list of differences is returned straight away.
*
* @param oldAnnotation the annotation in the old API
* @param newAnnotation the annotation in the new API
*
* @return the list of differences between the two annotations
*/
@Nullable
List<Difference> visitAnnotation(@Nullable JavaAnnotationElement oldAnnotation,
@Nullable JavaAnnotationElement newAnnotation);
enum Type {
CLASS, METHOD, METHOD_PARAMETER, FIELD, ANNOTATION
}
}