DefaultDataContextPlugin.java
/* Contributed in the public domain.
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You 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.orekit.compiler.plugin;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.tools.Diagnostic;
import java.util.EnumSet;
import java.util.Set;
import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.JavacTask;
import com.sun.source.util.Plugin;
import com.sun.source.util.TaskEvent;
import com.sun.source.util.TaskEvent.Kind;
import com.sun.source.util.TaskListener;
import com.sun.source.util.TreePath;
import com.sun.source.util.TreeScanner;
import com.sun.source.util.Trees;
import org.orekit.annotation.DefaultDataContext;
/**
* Processes {@link DefaultDataContext} to issue warnings at compile time.
*
* <p>To use this plugin add {@code -Xplugin:dataContextPlugin} to the javac command line.
* Tested with OpenJDK 8 and 11.
*
* <p>Do not reference this class unless executing within {@code javac} or you have added
* {@code tools.jar} to the class path. {@code tools.jar} is part of the JDK, not JRE, and
* is typically located at {@code JAVA_HOME/../lib/tools.jar}.
*
* @author Evan Ward
* @since 10.1
*/
@SupportedAnnotationTypes("org.orekit.annotation.DefaultDataContext")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class DefaultDataContextPlugin implements Plugin, TaskListener {
/** Warning message. */
static final String MESSAGE = "Use of the default data context from a scope not " +
"annotated with @DefaultDataContext. This code may be unintentionally " +
"using the default data context.";
/** Annotation to search for. */
private static final Class<DefaultDataContext> ANNOTATION = DefaultDataContext.class;
/** Compiler Trees. */
private Trees trees;
@Override
public String getName() {
return "dataContextPlugin";
}
@Override
public synchronized void init(final JavacTask javacTask, final String... args) {
javacTask.addTaskListener(this);
trees = Trees.instance(javacTask);
}
@Override
public void started(final TaskEvent taskEvent) {
}
@Override
public void finished(final TaskEvent taskEvent) {
if (taskEvent.getKind() == Kind.ANALYZE) {
final CompilationUnitTree root = taskEvent.getCompilationUnit();
root.accept(new AnnotationTreeScanner(root), null);
}
}
/** Finds when an annotation is used and checks the scope has the same annotation. */
private class AnnotationTreeScanner extends TreeScanner<Void, Void> {
/** Compilation root. */
private final CompilationUnitTree root;
/**
* Create a scanner.
*
* @param root of the compilation.
*/
AnnotationTreeScanner(final CompilationUnitTree root) {
this.root = root;
}
@Override
public Void visitIdentifier(final IdentifierTree identifierTree,
final Void aVoid) {
check(identifierTree);
return super.visitIdentifier(identifierTree, aVoid);
}
@Override
public Void visitMemberSelect(final MemberSelectTree memberSelectTree,
final Void aVoid) {
check(memberSelectTree);
return super.visitMemberSelect(memberSelectTree, aVoid);
}
@Override
public Void visitNewClass(final NewClassTree newClassTree, final Void aVoid) {
check(newClassTree);
return super.visitNewClass(newClassTree, aVoid);
}
/**
* Check if this bit of code calls into the default data context from outside the
* default data context.
*
* @param tree to check.
*/
private void check(final Tree tree) {
final Element element = trees.getElement(trees.getPath(root, tree));
check(tree, element);
}
/**
* Check tricky bits of code.
*
* @param tree used to check the containing scope and for logging.
* @param element to check for {@link #ANNOTATION}.
*/
private void check(final Tree tree, final Element element) {
// element and its containing scopes.
if (isAnyElementAnnotated(element)) {
// using code annotated with @DefaultDataContext
// check if current scope is also annotated
if (!isAnyElementAnnotated(trees.getPath(root, tree))) {
// calling the default data context from a method without an annotation
final String message = MESSAGE + " Used: " + element.getKind() + " " + element;
trees.printMessage(Diagnostic.Kind.WARNING, message, tree, root);
}
}
}
/**
* Determine if any enclosing element has {@link #ANNOTATION}. Walks towards the
* tree root checking each node for the annotation.
*
* @param element to start the search from. May be {@code null}.
* @return {@code true} if {@code element} or any of its parents are annotated,
* {@code false} otherwise.
*/
private boolean isAnyElementAnnotated(final Element element) {
Element e = element;
while (e != null) {
if (e.getAnnotation(ANNOTATION) != null) {
return true;
}
e = e.getEnclosingElement();
}
return false;
}
/**
* Determine if any enclosing tree has {@link #ANNOTATION}. Walks towards the tree
* root checking each node for the annotation.
*
* @param path to start the search from. May be {@code null}.
* @return {@code true} if {@code path} or any of its parents are annotated,
* {@code false} otherwise.
*/
private boolean isAnyElementAnnotated(final TreePath path) {
// Kinds of declarations which can be annotated
final Set<Tree.Kind> toCheck = EnumSet.of(
Tree.Kind.METHOD, Tree.Kind.CLASS, Tree.Kind.VARIABLE,
Tree.Kind.INTERFACE, Tree.Kind.ENUM);
TreePath next = path;
while (next != null) {
if (toCheck.contains(next.getLeaf().getKind())) {
if (trees.getElement(next).getAnnotation(ANNOTATION) != null) {
return true;
}
}
next = next.getParentPath();
}
return false;
}
}
}