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The Checker Framework enhances Java's type system to
make it more powerful and useful. This lets software developers
detect and prevent errors in their Java programs.
The Checker Framework includes compiler plug-ins ("checkers")
that find bugs or verify their absence. It also permits you to
write your own compiler plug-ins.
package org.checkerframework.framework.util.element;
import com.sun.source.tree.LambdaExpressionTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Attribute.TypeCompound;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.TargetType;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.VariableElement;
import org.checkerframework.framework.type.AnnotatedTypeFactory;
import org.checkerframework.framework.type.AnnotatedTypeMirror;
import org.checkerframework.framework.type.ElementAnnotationApplier;
import org.checkerframework.framework.util.element.ElementAnnotationUtil.UnexpectedAnnotationLocationException;
import org.checkerframework.javacutil.BugInCF;
import org.checkerframework.javacutil.Pair;
/** Adds annotations to one formal parameter of a method or lambda within a method. */
public class ParamApplier extends IndexedElementAnnotationApplier {
/** Apply annotations from {@code element} to {@code type}. */
public static void apply(
AnnotatedTypeMirror type, Element element, AnnotatedTypeFactory typeFactory)
throws UnexpectedAnnotationLocationException {
new ParamApplier(type, element, typeFactory).extractAndApply();
}
public static final int RECEIVER_PARAM_INDEX = Integer.MIN_VALUE;
public static boolean accepts(final AnnotatedTypeMirror type, final Element element) {
return element.getKind() == ElementKind.PARAMETER;
}
private final Symbol.MethodSymbol enclosingMethod;
private final boolean isLambdaParam;
private final Integer lambdaParamIndex;
private final LambdaExpressionTree lambdaTree;
ParamApplier(AnnotatedTypeMirror type, Element element, AnnotatedTypeFactory typeFactory) {
super(type, element);
enclosingMethod = getParentMethod(element);
if (enclosingMethod.getKind() != ElementKind.INSTANCE_INIT
&& enclosingMethod.getKind() != ElementKind.STATIC_INIT
&& enclosingMethod.getParameters().contains(element)) {
lambdaTree = null;
isLambdaParam = false;
lambdaParamIndex = null;
} else {
Pair paramToEnclosingLambda =
ElementAnnotationApplier.getParamAndLambdaTree((VariableElement) element, typeFactory);
if (paramToEnclosingLambda != null) {
VariableTree paramDecl = paramToEnclosingLambda.first;
lambdaTree = paramToEnclosingLambda.second;
isLambdaParam = true;
lambdaParamIndex = lambdaTree.getParameters().indexOf(paramDecl);
} else {
lambdaTree = null;
isLambdaParam = false;
lambdaParamIndex = null;
}
}
}
/**
* Returns the index of element its parent method's parameter list. Integer.MIN_VALUE if the
* element is the receiver parameter.
*
* @return the index of element its parent method's parameter list. Integer.MIN_VALUE if the
* element is the receiver parameter
*/
@Override
public int getElementIndex() {
if (isLambdaParam) {
return lambdaParamIndex;
}
if (isReceiver(element)) {
return RECEIVER_PARAM_INDEX;
}
final int paramIndex = enclosingMethod.getParameters().indexOf(element);
if (paramIndex == -1) {
throw new BugInCF(
"Could not find parameter Element in parameter list. "
+ "Parameter( "
+ element
+ " ) Parent ( "
+ enclosingMethod
+ " ) ");
}
return paramIndex;
}
/**
* Returns the parameter index of anno's TypeAnnotationPosition.
*
* @return the parameter index of anno's TypeAnnotationPosition
*/
@Override
public int getTypeCompoundIndex(Attribute.TypeCompound anno) {
return anno.getPosition().parameter_index;
}
/**
* Returns {TargetType.METHOD_FORMAL_PARAMETER, TargetType.METHOD_RECEIVER}.
*
* @return {TargetType.METHOD_FORMAL_PARAMETER, TargetType.METHOD_RECEIVER}
*/
@Override
protected TargetType[] annotatedTargets() {
return new TargetType[] {TargetType.METHOD_FORMAL_PARAMETER, TargetType.METHOD_RECEIVER};
}
/**
* Returns any annotation TargetType that can be found on a method.
*
* @return any annotation TargetType that can be found on a method
*/
@Override
protected TargetType[] validTargets() {
return new TargetType[] {
TargetType.METHOD_FORMAL_PARAMETER,
TargetType.METHOD_RETURN,
TargetType.THROWS,
TargetType.METHOD_TYPE_PARAMETER,
TargetType.METHOD_TYPE_PARAMETER_BOUND,
TargetType.LOCAL_VARIABLE,
TargetType.RESOURCE_VARIABLE,
TargetType.EXCEPTION_PARAMETER,
TargetType.NEW,
TargetType.CAST,
TargetType.INSTANCEOF,
TargetType.METHOD_INVOCATION_TYPE_ARGUMENT,
TargetType.CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT,
TargetType.METHOD_REFERENCE,
TargetType.CONSTRUCTOR_REFERENCE,
TargetType.METHOD_REFERENCE_TYPE_ARGUMENT,
TargetType.CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT,
// TODO: from generic anonymous classes; remove when
// we can depend on only seeing classfiles that were
// generated by a javac that contains a fix for:
// https://bugs.openjdk.java.net/browse/JDK-8198945
TargetType.CLASS_EXTENDS
};
}
/**
* Returns the TypeCompounds (annotations) of the enclosing method for this parameter.
*
* @return the TypeCompounds (annotations) of the enclosing method for this parameter
*/
@Override
protected Iterable getRawTypeAttributes() {
return enclosingMethod.getRawTypeAttributes();
}
@Override
protected Map> sift(
Iterable typeCompounds) {
// this will sift out the annotations that do not have the right position index
final Map> targetClassToAnnos =
super.sift(typeCompounds);
final List targeted = targetClassToAnnos.get(TargetClass.TARGETED);
final List valid = targetClassToAnnos.get(TargetClass.VALID);
// if this is a lambdaParam, filter out from targeted those annos that apply to method
// formal parameters if this is a method formal param, filter out from targeted those annos
// that apply to lambdas
int i = 0;
while (i < targeted.size()) {
final Tree onLambda = targeted.get(i).position.onLambda;
if (onLambda == null) {
if (!isLambdaParam) {
++i;
} else {
valid.add(targeted.remove(i));
}
} else {
if (onLambda.equals(this.lambdaTree)) {
++i;
} else {
valid.add(targeted.remove(i));
}
}
}
return targetClassToAnnos;
}
/**
* @param targeted type compounds with formal method parameter target types with parameter_index
* == getIndex
*/
@Override
protected void handleTargeted(final List targeted)
throws UnexpectedAnnotationLocationException {
final List formalParams = new ArrayList<>();
Map> targetToAnnos =
ElementAnnotationUtil.partitionByTargetType(
targeted, formalParams, TargetType.METHOD_RECEIVER);
if (isReceiver(element)) {
ElementAnnotationUtil.annotateViaTypeAnnoPosition(
type, targetToAnnos.get(TargetType.METHOD_RECEIVER));
} else {
ElementAnnotationUtil.annotateViaTypeAnnoPosition(type, formalParams);
}
}
/**
* Returns true if element represents the receiver parameter of a method.
*
* @param element an element
* @return true if element represents the receiver parameter of a method
*/
private boolean isReceiver(final Element element) {
return element.getKind() == ElementKind.PARAMETER
&& element.getSimpleName().contentEquals("this");
}
@Override
protected boolean isAccepted() {
return accepts(type, element);
}
/**
* Return the enclosing MethodSymbol of the given element, throwing an exception of the symbol's
* enclosing element is not a MethodSymbol.
*
* @param methodChildElem some element that is a child of a method typeDeclaration (e.g. a
* parameter or return type)
* @return the MethodSymbol of the method containing methodChildElem
*/
public static Symbol.MethodSymbol getParentMethod(final Element methodChildElem) {
if (!(methodChildElem.getEnclosingElement() instanceof Symbol.MethodSymbol)) {
throw new BugInCF(
"Element is not a direct child of a MethodSymbol. Element ( "
+ methodChildElem
+ " parent ( "
+ methodChildElem.getEnclosingElement()
+ " ) ");
}
return (Symbol.MethodSymbol) methodChildElem.getEnclosingElement();
}
@Override
public void extractAndApply() throws UnexpectedAnnotationLocationException {
ElementAnnotationUtil.addDeclarationAnnotationsFromElement(
type, element.getAnnotationMirrors());
super.extractAndApply();
}
}