FinalLocalVariableCheck.java
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2021 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.coding;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Deque;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Optional;
import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
/**
* <p>
* Checks that local variables that never have their values changed are declared final.
* The check can be configured to also check that unchanged parameters are declared final.
* </p>
* <p>
* When configured to check parameters, the check ignores parameters of interface
* methods and abstract methods.
* </p>
* <ul>
* <li>
* Property {@code validateEnhancedForLoopVariable} - Control whether to check
* <a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-14.html#jls-14.14.2">
* enhanced for-loop</a> variable.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* <li>
* Property {@code tokens} - tokens to check
* Type is {@code java.lang.String[]}.
* Validation type is {@code tokenSet}.
* Default value is:
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
* VARIABLE_DEF</a>.
* </li>
* </ul>
* <p>
* To configure the check:
* </p>
* <pre>
* <module name="FinalLocalVariable"/>
* </pre>
* <p>
* To configure the check so that it checks local variables and parameters:
* </p>
* <pre>
* <module name="FinalLocalVariable">
* <property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
* </module>
* </pre>
* <p>
* By default, this Check skip final validation on
* <a href = "https://docs.oracle.com/javase/specs/jls/se11/html/jls-14.html#jls-14.14.2">
* Enhanced For-Loop</a>.
* </p>
* <p>
* Option 'validateEnhancedForLoopVariable' could be used to make Check to validate even variable
* from Enhanced For Loop.
* </p>
* <p>
* An example of how to configure the check so that it also validates enhanced For Loop Variable is:
* </p>
* <pre>
* <module name="FinalLocalVariable">
* <property name="tokens" value="VARIABLE_DEF"/>
* <property name="validateEnhancedForLoopVariable" value="true"/>
* </module>
* </pre>
* <p>Example:</p>
* <pre>
* for (int number : myNumbers) { // violation
* System.out.println(number);
* }
* </pre>
* <p>
* An example of how to configure check on local variables and parameters
* but do not validate loop variables:
* </p>
* <pre>
* <module name="FinalLocalVariable">
* <property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
* <property name="validateEnhancedForLoopVariable" value="false"/>
* </module>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* public class MyClass {
* static int foo(int x, int y) { //violations, parameters should be final
* return x+y;
* }
* public static void main (String []args) { //violation, parameters should be final
* for (String i : args) {
* System.out.println(i);
* }
* int result=foo(1,2); // violation
* }
* }
* </pre>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code final.variable}
* </li>
* </ul>
*
* @since 3.2
*/
@FileStatefulCheck
public class FinalLocalVariableCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "final.variable";
/**
* Assign operator types.
*/
private static final int[] ASSIGN_OPERATOR_TYPES = {
TokenTypes.POST_INC,
TokenTypes.POST_DEC,
TokenTypes.ASSIGN,
TokenTypes.PLUS_ASSIGN,
TokenTypes.MINUS_ASSIGN,
TokenTypes.STAR_ASSIGN,
TokenTypes.DIV_ASSIGN,
TokenTypes.MOD_ASSIGN,
TokenTypes.SR_ASSIGN,
TokenTypes.BSR_ASSIGN,
TokenTypes.SL_ASSIGN,
TokenTypes.BAND_ASSIGN,
TokenTypes.BXOR_ASSIGN,
TokenTypes.BOR_ASSIGN,
TokenTypes.INC,
TokenTypes.DEC,
};
/**
* Loop types.
*/
private static final int[] LOOP_TYPES = {
TokenTypes.LITERAL_FOR,
TokenTypes.LITERAL_WHILE,
TokenTypes.LITERAL_DO,
};
/** Scope Deque. */
private final Deque<ScopeData> scopeStack = new ArrayDeque<>();
/** Uninitialized variables of previous scope. */
private final Deque<Deque<DetailAST>> prevScopeUninitializedVariables =
new ArrayDeque<>();
/** Assigned variables of current scope. */
private final Deque<Deque<DetailAST>> currentScopeAssignedVariables =
new ArrayDeque<>();
/**
* Control whether to check
* <a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-14.html#jls-14.14.2">
* enhanced for-loop</a> variable.
*/
private boolean validateEnhancedForLoopVariable;
static {
// Array sorting for binary search
Arrays.sort(ASSIGN_OPERATOR_TYPES);
Arrays.sort(LOOP_TYPES);
}
/**
* Setter to control whether to check
* <a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-14.html#jls-14.14.2">
* enhanced for-loop</a> variable.
*
* @param validateEnhancedForLoopVariable whether to check for-loop variable
*/
public final void setValidateEnhancedForLoopVariable(boolean validateEnhancedForLoopVariable) {
this.validateEnhancedForLoopVariable = validateEnhancedForLoopVariable;
}
@Override
public int[] getRequiredTokens() {
return new int[] {
TokenTypes.IDENT,
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.SLIST,
TokenTypes.OBJBLOCK,
TokenTypes.LITERAL_BREAK,
TokenTypes.LITERAL_FOR,
TokenTypes.EXPR,
};
}
@Override
public int[] getDefaultTokens() {
return new int[] {
TokenTypes.IDENT,
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.SLIST,
TokenTypes.OBJBLOCK,
TokenTypes.LITERAL_BREAK,
TokenTypes.LITERAL_FOR,
TokenTypes.VARIABLE_DEF,
TokenTypes.EXPR,
};
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.IDENT,
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.SLIST,
TokenTypes.OBJBLOCK,
TokenTypes.LITERAL_BREAK,
TokenTypes.LITERAL_FOR,
TokenTypes.VARIABLE_DEF,
TokenTypes.PARAMETER_DEF,
TokenTypes.EXPR,
};
}
// -@cs[CyclomaticComplexity] The only optimization which can be done here is moving CASE-block
// expressions to separate methods, but that will not increase readability.
@Override
public void visitToken(DetailAST ast) {
switch (ast.getType()) {
case TokenTypes.OBJBLOCK:
case TokenTypes.METHOD_DEF:
case TokenTypes.CTOR_DEF:
case TokenTypes.LITERAL_FOR:
scopeStack.push(new ScopeData());
break;
case TokenTypes.SLIST:
currentScopeAssignedVariables.push(new ArrayDeque<>());
if (ast.getParent().getType() != TokenTypes.CASE_GROUP
|| ast.getParent().getParent().findFirstToken(TokenTypes.CASE_GROUP)
== ast.getParent()) {
storePrevScopeUninitializedVariableData();
scopeStack.push(new ScopeData());
}
break;
case TokenTypes.PARAMETER_DEF:
if (!isInLambda(ast)
&& ast.findFirstToken(TokenTypes.MODIFIERS)
.findFirstToken(TokenTypes.FINAL) == null
&& !isInAbstractOrNativeMethod(ast)
&& !ScopeUtil.isInInterfaceBlock(ast)
&& !isMultipleTypeCatch(ast)
&& !CheckUtil.isReceiverParameter(ast)) {
insertParameter(ast);
}
break;
case TokenTypes.VARIABLE_DEF:
if (ast.getParent().getType() != TokenTypes.OBJBLOCK
&& ast.findFirstToken(TokenTypes.MODIFIERS)
.findFirstToken(TokenTypes.FINAL) == null
&& !isVariableInForInit(ast)
&& shouldCheckEnhancedForLoopVariable(ast)) {
insertVariable(ast);
}
break;
case TokenTypes.IDENT:
final int parentType = ast.getParent().getType();
if (isAssignOperator(parentType) && isFirstChild(ast)) {
final Optional<FinalVariableCandidate> candidate = getFinalCandidate(ast);
if (candidate.isPresent()) {
determineAssignmentConditions(ast, candidate.get());
currentScopeAssignedVariables.peek().add(ast);
}
removeFinalVariableCandidateFromStack(ast);
}
break;
case TokenTypes.LITERAL_BREAK:
scopeStack.peek().containsBreak = true;
break;
case TokenTypes.EXPR:
// Switch labeled expression has no slist
if (ast.getParent().getType() == TokenTypes.SWITCH_RULE
&& ast.getParent().getParent().findFirstToken(TokenTypes.SWITCH_RULE)
== ast.getParent()) {
storePrevScopeUninitializedVariableData();
}
break;
default:
throw new IllegalStateException("Incorrect token type");
}
}
@Override
public void leaveToken(DetailAST ast) {
Map<String, FinalVariableCandidate> scope = null;
final Deque<DetailAST> prevScopeUninitializedVariableData;
switch (ast.getType()) {
case TokenTypes.OBJBLOCK:
case TokenTypes.CTOR_DEF:
case TokenTypes.METHOD_DEF:
case TokenTypes.LITERAL_FOR:
scope = scopeStack.pop().scope;
break;
case TokenTypes.EXPR:
// Switch labeled expression has no slist
if (ast.getParent().getType() == TokenTypes.SWITCH_RULE) {
prevScopeUninitializedVariableData = prevScopeUninitializedVariables.peek();
if (shouldUpdateUninitializedVariables(ast.getParent())) {
updateAllUninitializedVariables(prevScopeUninitializedVariableData);
}
}
break;
case TokenTypes.SLIST:
prevScopeUninitializedVariableData = prevScopeUninitializedVariables.peek();
boolean containsBreak = false;
if (ast.getParent().getType() != TokenTypes.CASE_GROUP
|| findLastChildWhichContainsSpecifiedToken(ast.getParent().getParent(),
TokenTypes.CASE_GROUP, TokenTypes.SLIST) == ast.getParent()) {
containsBreak = scopeStack.peek().containsBreak;
scope = scopeStack.pop().scope;
prevScopeUninitializedVariables.pop();
}
final DetailAST parent = ast.getParent();
if (containsBreak || shouldUpdateUninitializedVariables(parent)) {
updateAllUninitializedVariables(prevScopeUninitializedVariableData);
}
updateCurrentScopeAssignedVariables();
break;
default:
// do nothing
}
if (scope != null) {
for (FinalVariableCandidate candidate : scope.values()) {
final DetailAST ident = candidate.variableIdent;
log(ident, MSG_KEY, ident.getText());
}
}
}
/**
* Update assigned variables in a temporary stack.
*/
private void updateCurrentScopeAssignedVariables() {
// -@cs[MoveVariableInsideIf] assignment value is a modification call so it can't be moved
final Deque<DetailAST> poppedScopeAssignedVariableData =
currentScopeAssignedVariables.pop();
final Deque<DetailAST> currentScopeAssignedVariableData =
currentScopeAssignedVariables.peek();
if (currentScopeAssignedVariableData != null) {
currentScopeAssignedVariableData.addAll(poppedScopeAssignedVariableData);
}
}
/**
* Determines identifier assignment conditions (assigned or already assigned).
*
* @param ident identifier.
* @param candidate final local variable candidate.
*/
private static void determineAssignmentConditions(DetailAST ident,
FinalVariableCandidate candidate) {
if (candidate.assigned) {
final int[] blockTypes = {
TokenTypes.LITERAL_ELSE,
TokenTypes.CASE_GROUP,
TokenTypes.SWITCH_RULE,
};
if (!isInSpecificCodeBlocks(ident, blockTypes)) {
candidate.alreadyAssigned = true;
}
}
else {
candidate.assigned = true;
}
}
/**
* Checks whether the scope of a node is restricted to a specific code blocks.
*
* @param node node.
* @param blockTypes int array of all block types to check.
* @return true if the scope of a node is restricted to specific code block types.
*/
private static boolean isInSpecificCodeBlocks(DetailAST node, int... blockTypes) {
boolean returnValue = false;
for (int blockType : blockTypes) {
for (DetailAST token = node.getParent(); token != null; token = token.getParent()) {
final int type = token.getType();
if (type == blockType) {
returnValue = true;
break;
}
}
}
return returnValue;
}
/**
* Gets final variable candidate for ast.
*
* @param ast ast.
* @return Optional of {@link FinalVariableCandidate} for ast from scopeStack.
*/
private Optional<FinalVariableCandidate> getFinalCandidate(DetailAST ast) {
Optional<FinalVariableCandidate> result = Optional.empty();
final Iterator<ScopeData> iterator = scopeStack.descendingIterator();
while (iterator.hasNext() && !result.isPresent()) {
final ScopeData scopeData = iterator.next();
result = scopeData.findFinalVariableCandidateForAst(ast);
}
return result;
}
/**
* Store un-initialized variables in a temporary stack for future use.
*/
private void storePrevScopeUninitializedVariableData() {
final ScopeData scopeData = scopeStack.peek();
final Deque<DetailAST> prevScopeUninitializedVariableData =
new ArrayDeque<>();
scopeData.uninitializedVariables.forEach(prevScopeUninitializedVariableData::push);
prevScopeUninitializedVariables.push(prevScopeUninitializedVariableData);
}
/**
* Update current scope data uninitialized variable according to the whole scope data.
*
* @param prevScopeUninitializedVariableData variable for previous stack of uninitialized
* variables
* @noinspection MethodParameterNamingConvention
*/
private void updateAllUninitializedVariables(
Deque<DetailAST> prevScopeUninitializedVariableData) {
final boolean hasSomeScopes = !currentScopeAssignedVariables.isEmpty();
if (hasSomeScopes) {
// Check for only previous scope
updateUninitializedVariables(prevScopeUninitializedVariableData);
// Check for rest of the scope
prevScopeUninitializedVariables.forEach(this::updateUninitializedVariables);
}
}
/**
* Update current scope data uninitialized variable according to the specific scope data.
*
* @param scopeUninitializedVariableData variable for specific stack of uninitialized variables
*/
private void updateUninitializedVariables(Deque<DetailAST> scopeUninitializedVariableData) {
final Iterator<DetailAST> iterator = currentScopeAssignedVariables.peek().iterator();
while (iterator.hasNext()) {
final DetailAST assignedVariable = iterator.next();
boolean shouldRemove = false;
for (DetailAST variable : scopeUninitializedVariableData) {
for (ScopeData scopeData : scopeStack) {
final FinalVariableCandidate candidate =
scopeData.scope.get(variable.getText());
DetailAST storedVariable = null;
if (candidate != null) {
storedVariable = candidate.variableIdent;
}
if (storedVariable != null
&& isSameVariables(storedVariable, variable)
&& isSameVariables(assignedVariable, variable)) {
scopeData.uninitializedVariables.push(variable);
shouldRemove = true;
}
}
}
if (shouldRemove) {
iterator.remove();
}
}
}
/**
* If token is LITERAL_IF and there is an {@code else} following or token is CASE_GROUP or
* SWITCH_RULE and there is another {@code case} following, then update the
* uninitialized variables.
*
* @param ast token to be checked
* @return true if should be updated, else false
*/
private static boolean shouldUpdateUninitializedVariables(DetailAST ast) {
return isIfTokenWithAnElseFollowing(ast) || isCaseTokenWithAnotherCaseFollowing(ast);
}
/**
* If token is LITERAL_IF and there is an {@code else} following.
*
* @param ast token to be checked
* @return true if token is LITERAL_IF and there is an {@code else} following, else false
*/
private static boolean isIfTokenWithAnElseFollowing(DetailAST ast) {
return ast.getType() == TokenTypes.LITERAL_IF
&& ast.getLastChild().getType() == TokenTypes.LITERAL_ELSE;
}
/**
* If token is CASE_GROUP or SWITCH_RULE and there is another {@code case} following.
*
* @param ast token to be checked
* @return true if token is CASE_GROUP or SWITCH_RULE and there is another {@code case}
* following, else false
*/
private static boolean isCaseTokenWithAnotherCaseFollowing(DetailAST ast) {
boolean result = false;
if (ast.getType() == TokenTypes.CASE_GROUP) {
result = findLastChildWhichContainsSpecifiedToken(
ast.getParent(), TokenTypes.CASE_GROUP, TokenTypes.SLIST) != ast;
}
else if (ast.getType() == TokenTypes.SWITCH_RULE) {
result = ast.getNextSibling().getType() == TokenTypes.SWITCH_RULE;
}
return result;
}
/**
* Returns the last child token that makes a specified type and contains containType in
* its branch.
*
* @param ast token to be tested
* @param childType the token type to match
* @param containType the token type which has to be present in the branch
* @return the matching token, or null if no match
*/
private static DetailAST findLastChildWhichContainsSpecifiedToken(DetailAST ast, int childType,
int containType) {
DetailAST returnValue = null;
for (DetailAST astIterator = ast.getFirstChild(); astIterator != null;
astIterator = astIterator.getNextSibling()) {
if (astIterator.getType() == childType
&& astIterator.findFirstToken(containType) != null) {
returnValue = astIterator;
}
}
return returnValue;
}
/**
* Determines whether enhanced for-loop variable should be checked or not.
*
* @param ast The ast to compare.
* @return true if enhanced for-loop variable should be checked.
*/
private boolean shouldCheckEnhancedForLoopVariable(DetailAST ast) {
return validateEnhancedForLoopVariable
|| ast.getParent().getType() != TokenTypes.FOR_EACH_CLAUSE;
}
/**
* Insert a parameter at the topmost scope stack.
*
* @param ast the variable to insert.
*/
private void insertParameter(DetailAST ast) {
final Map<String, FinalVariableCandidate> scope = scopeStack.peek().scope;
final DetailAST astNode = ast.findFirstToken(TokenTypes.IDENT);
scope.put(astNode.getText(), new FinalVariableCandidate(astNode));
}
/**
* Insert a variable at the topmost scope stack.
*
* @param ast the variable to insert.
*/
private void insertVariable(DetailAST ast) {
final Map<String, FinalVariableCandidate> scope = scopeStack.peek().scope;
final DetailAST astNode = ast.findFirstToken(TokenTypes.IDENT);
final FinalVariableCandidate candidate = new FinalVariableCandidate(astNode);
// for-each variables are implicitly assigned
candidate.assigned = ast.getParent().getType() == TokenTypes.FOR_EACH_CLAUSE;
scope.put(astNode.getText(), candidate);
if (!isInitialized(astNode)) {
scopeStack.peek().uninitializedVariables.add(astNode);
}
}
/**
* Check if VARIABLE_DEF is initialized or not.
*
* @param ast VARIABLE_DEF to be checked
* @return true if initialized
*/
private static boolean isInitialized(DetailAST ast) {
return ast.getParent().getLastChild().getType() == TokenTypes.ASSIGN;
}
/**
* Whether the ast is the first child of its parent.
*
* @param ast the ast to check.
* @return true if the ast is the first child of its parent.
*/
private static boolean isFirstChild(DetailAST ast) {
return ast.getPreviousSibling() == null;
}
/**
* Removes the final variable candidate from the Stack.
*
* @param ast variable to remove.
*/
private void removeFinalVariableCandidateFromStack(DetailAST ast) {
final Iterator<ScopeData> iterator = scopeStack.descendingIterator();
while (iterator.hasNext()) {
final ScopeData scopeData = iterator.next();
final Map<String, FinalVariableCandidate> scope = scopeData.scope;
final FinalVariableCandidate candidate = scope.get(ast.getText());
DetailAST storedVariable = null;
if (candidate != null) {
storedVariable = candidate.variableIdent;
}
if (storedVariable != null && isSameVariables(storedVariable, ast)) {
if (shouldRemoveFinalVariableCandidate(scopeData, ast)) {
scope.remove(ast.getText());
}
break;
}
}
}
/**
* Check if given parameter definition is a multiple type catch.
*
* @param parameterDefAst parameter definition
* @return true if it is a multiple type catch, false otherwise
*/
private static boolean isMultipleTypeCatch(DetailAST parameterDefAst) {
final DetailAST typeAst = parameterDefAst.findFirstToken(TokenTypes.TYPE);
return typeAst.getFirstChild().getType() == TokenTypes.BOR;
}
/**
* Whether the final variable candidate should be removed from the list of final local variable
* candidates.
*
* @param scopeData the scope data of the variable.
* @param ast the variable ast.
* @return true, if the variable should be removed.
*/
private static boolean shouldRemoveFinalVariableCandidate(ScopeData scopeData, DetailAST ast) {
boolean shouldRemove = true;
for (DetailAST variable : scopeData.uninitializedVariables) {
if (variable.getText().equals(ast.getText())) {
// if the variable is declared outside the loop and initialized inside
// the loop, then it cannot be declared final, as it can be initialized
// more than once in this case
if (isInTheSameLoop(variable, ast) || !isUseOfExternalVariableInsideLoop(ast)) {
final FinalVariableCandidate candidate = scopeData.scope.get(ast.getText());
shouldRemove = candidate.alreadyAssigned;
}
scopeData.uninitializedVariables.remove(variable);
break;
}
}
return shouldRemove;
}
/**
* Checks whether a variable which is declared outside loop is used inside loop.
* For example:
* <p>
* {@code
* int x;
* for (int i = 0, j = 0; i < j; i++) {
* x = 5;
* }
* }
* </p>
*
* @param variable variable.
* @return true if a variable which is declared outside loop is used inside loop.
*/
private static boolean isUseOfExternalVariableInsideLoop(DetailAST variable) {
DetailAST loop2 = variable.getParent();
while (loop2 != null
&& !isLoopAst(loop2.getType())) {
loop2 = loop2.getParent();
}
return loop2 != null;
}
/**
* Is Arithmetic operator.
*
* @param parentType token AST
* @return true is token type is in arithmetic operator
*/
private static boolean isAssignOperator(int parentType) {
return Arrays.binarySearch(ASSIGN_OPERATOR_TYPES, parentType) >= 0;
}
/**
* Checks if current variable is defined in
* {@link TokenTypes#FOR_INIT for-loop init}, e.g.:
* <p>
* {@code
* for (int i = 0, j = 0; i < j; i++) { . . . }
* }
* </p>
* {@code i, j} are defined in {@link TokenTypes#FOR_INIT for-loop init}
*
* @param variableDef variable definition node.
* @return true if variable is defined in {@link TokenTypes#FOR_INIT for-loop init}
*/
private static boolean isVariableInForInit(DetailAST variableDef) {
return variableDef.getParent().getType() == TokenTypes.FOR_INIT;
}
/**
* Determines whether an AST is a descendant of an abstract or native method.
*
* @param ast the AST to check.
* @return true if ast is a descendant of an abstract or native method.
*/
private static boolean isInAbstractOrNativeMethod(DetailAST ast) {
boolean abstractOrNative = false;
DetailAST parent = ast.getParent();
while (parent != null && !abstractOrNative) {
if (parent.getType() == TokenTypes.METHOD_DEF) {
final DetailAST modifiers =
parent.findFirstToken(TokenTypes.MODIFIERS);
abstractOrNative = modifiers.findFirstToken(TokenTypes.ABSTRACT) != null
|| modifiers.findFirstToken(TokenTypes.LITERAL_NATIVE) != null;
}
parent = parent.getParent();
}
return abstractOrNative;
}
/**
* Check if current param is lambda's param.
*
* @param paramDef {@link TokenTypes#PARAMETER_DEF parameter def}.
* @return true if current param is lambda's param.
*/
private static boolean isInLambda(DetailAST paramDef) {
return paramDef.getParent().getParent().getType() == TokenTypes.LAMBDA;
}
/**
* Find the Class, Constructor, Enum, Method, or Field in which it is defined.
*
* @param ast Variable for which we want to find the scope in which it is defined
* @return ast The Class or Constructor or Method in which it is defined.
*/
private static DetailAST findFirstUpperNamedBlock(DetailAST ast) {
DetailAST astTraverse = ast;
while (!TokenUtil.isOfType(astTraverse, TokenTypes.METHOD_DEF, TokenTypes.CLASS_DEF,
TokenTypes.ENUM_DEF, TokenTypes.CTOR_DEF, TokenTypes.COMPACT_CTOR_DEF)
&& !ScopeUtil.isClassFieldDef(astTraverse)) {
astTraverse = astTraverse.getParent();
}
return astTraverse;
}
/**
* Check if both the Variables are same.
*
* @param ast1 Variable to compare
* @param ast2 Variable to compare
* @return true if both the variables are same, otherwise false
*/
private static boolean isSameVariables(DetailAST ast1, DetailAST ast2) {
final DetailAST classOrMethodOfAst1 =
findFirstUpperNamedBlock(ast1);
final DetailAST classOrMethodOfAst2 =
findFirstUpperNamedBlock(ast2);
return classOrMethodOfAst1 == classOrMethodOfAst2 && ast1.getText().equals(ast2.getText());
}
/**
* Check if both the variables are in the same loop.
*
* @param ast1 variable to compare.
* @param ast2 variable to compare.
* @return true if both the variables are in the same loop.
*/
private static boolean isInTheSameLoop(DetailAST ast1, DetailAST ast2) {
DetailAST loop1 = ast1.getParent();
while (loop1 != null && !isLoopAst(loop1.getType())) {
loop1 = loop1.getParent();
}
DetailAST loop2 = ast2.getParent();
while (loop2 != null && !isLoopAst(loop2.getType())) {
loop2 = loop2.getParent();
}
return loop1 != null && loop1 == loop2;
}
/**
* Checks whether the ast is a loop.
*
* @param ast the ast to check.
* @return true if the ast is a loop.
*/
private static boolean isLoopAst(int ast) {
return Arrays.binarySearch(LOOP_TYPES, ast) >= 0;
}
/**
* Holder for the scope data.
*/
private static class ScopeData {
/** Contains variable definitions. */
private final Map<String, FinalVariableCandidate> scope = new HashMap<>();
/** Contains definitions of uninitialized variables. */
private final Deque<DetailAST> uninitializedVariables = new ArrayDeque<>();
/** Whether there is a {@code break} in the scope. */
private boolean containsBreak;
/**
* Searches for final local variable candidate for ast in the scope.
*
* @param ast ast.
* @return Optional of {@link FinalVariableCandidate}.
*/
public Optional<FinalVariableCandidate> findFinalVariableCandidateForAst(DetailAST ast) {
Optional<FinalVariableCandidate> result = Optional.empty();
DetailAST storedVariable = null;
final Optional<FinalVariableCandidate> candidate =
Optional.ofNullable(scope.get(ast.getText()));
if (candidate.isPresent()) {
storedVariable = candidate.get().variableIdent;
}
if (storedVariable != null && isSameVariables(storedVariable, ast)) {
result = candidate;
}
return result;
}
}
/** Represents information about final local variable candidate. */
private static class FinalVariableCandidate {
/** Identifier token. */
private final DetailAST variableIdent;
/** Whether the variable is assigned. */
private boolean assigned;
/** Whether the variable is already assigned. */
private boolean alreadyAssigned;
/**
* Creates new instance.
*
* @param variableIdent variable identifier.
*/
/* package */ FinalVariableCandidate(DetailAST variableIdent) {
this.variableIdent = variableIdent;
}
}
}