VariableDeclarationUsageDistanceCheck.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.AbstractMap.SimpleEntry;
import java.util.ArrayList;
import java.util.List;
import java.util.Map.Entry;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.puppycrawl.tools.checkstyle.StatelessCheck;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.FullIdent;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
/**
* <p>
* Checks the distance between declaration of variable and its first usage.
* Note : Variable declaration/initialization statements are not counted while calculating length.
* </p>
* <ul>
* <li>
* Property {@code allowedDistance} - Specify distance between declaration
* of variable and its first usage. Values should be greater than 0.
* Type is {@code int}.
* Default value is {@code 3}.
* </li>
* <li>
* Property {@code ignoreVariablePattern} - Define RegExp to ignore distance calculation
* for variables listed in this pattern.
* Type is {@code java.util.regex.Pattern}.
* Default value is {@code ""}.
* </li>
* <li>
* Property {@code validateBetweenScopes} - Allow to calculate the distance between
* declaration of variable and its first usage in the different scopes.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* <li>
* Property {@code ignoreFinal} - Allow to ignore variables with a 'final' modifier.
* Type is {@code boolean}.
* Default value is {@code true}.
* </li>
* </ul>
* <p>
* To configure the check with default config:
* </p>
* <pre>
* <module name="VariableDeclarationUsageDistance"/>
* </pre>
* <p>Example:</p>
* <pre>
* public class Test {
*
* public void foo1() {
* int num; // violation, distance = 4
* final int PI; // OK, final variables not checked
* System.out.println("Statement 1");
* System.out.println("Statement 2");
* System.out.println("Statement 3");
* num = 1;
* PI = 3.14;
* }
*
* public void foo2() {
* int a; // OK, used in different scope
* int b; // OK, used in different scope
* int count = 0; // OK, used in different scope
*
* {
* System.out.println("Inside inner scope");
* a = 1;
* b = 2;
* count++;
* }
* }
* }
* </pre>
* <p>
* Check can detect a block of initialization methods. If a variable is used in
* such a block and there are no other statements after variable declaration, then distance = 1.
* </p>
* <p>Case #1:</p>
* <pre>
* int minutes = 5;
* Calendar cal = Calendar.getInstance();
* cal.setTimeInMillis(timeNow);
* cal.set(Calendar.SECOND, 0);
* cal.set(Calendar.MILLISECOND, 0);
* cal.set(Calendar.HOUR_OF_DAY, hh);
* cal.set(Calendar.MINUTE, minutes);
* </pre>
* <p>
* The distance for the variable "minutes" is 1 even
* though this variable is used in the fifth method's call.
* </p>
* <p>Case #2:</p>
* <pre>
* int minutes = 5;
* Calendar cal = Calendar.getInstance();
* cal.setTimeInMillis(timeNow);
* cal.set(Calendar.SECOND, 0);
* cal.set(Calendar.MILLISECOND, 0);
* <i>System.out.println(cal);</i>
* cal.set(Calendar.HOUR_OF_DAY, hh);
* cal.set(Calendar.MINUTE, minutes);
* </pre>
* <p>
* The distance for the variable "minutes" is 6 because there is one more expression
* (except the initialization block) between the declaration of this variable and its usage.
* </p>
* <p>
* To configure the check to set allowed distance:
* </p>
* <pre>
* <module name="VariableDeclarationUsageDistance">
* <property name="allowedDistance" value="4"/>
* </module>
* </pre>
* <p>Example:</p>
* <pre>
* public class Test {
*
* public void foo1() {
* int num; // OK, distance = 4
* final int PI; // OK, final variables not checked
* System.out.println("Statement 1");
* System.out.println("Statement 2");
* System.out.println("Statement 3");
* num = 1;
* PI = 3.14;
* }
*
* public void foo2() {
* int a; // OK, used in different scope
* int b; // OK, used in different scope
* int count = 0; // OK, used in different scope
*
* {
* System.out.println("Inside inner scope");
* a = 1;
* b = 2;
* count++;
* }
* }
* }
* </pre>
* <p>
* To configure the check to ignore certain variables:
* </p>
* <pre>
* <module name="VariableDeclarationUsageDistance">
* <property name="ignoreVariablePattern" value="^num$"/>
* </module>
* </pre>
* <p>
* This configuration ignores variables named "num".
* </p>
* <p>Example:</p>
* <pre>
* public class Test {
*
* public void foo1() {
* int num; // OK, variable ignored
* final int PI; // OK, final variables not checked
* System.out.println("Statement 1");
* System.out.println("Statement 2");
* System.out.println("Statement 3");
* num = 1;
* PI = 3.14;
* }
*
* public void foo2() {
* int a; // OK, used in different scope
* int b; // OK, used in different scope
* int count = 0; // OK, used in different scope
*
* {
* System.out.println("Inside inner scope");
* a = 1;
* b = 2;
* count++;
* }
* }
* }
* </pre>
* <p>
* To configure the check to force validation between scopes:
* </p>
* <pre>
* <module name="VariableDeclarationUsageDistance">
* <property name="validateBetweenScopes" value="true"/>
* </module>
* </pre>
* <p>Example:</p>
* <pre>
* public class Test {
*
* public void foo1() {
* int num; // violation, distance = 4
* final int PI; // OK, final variables not checked
* System.out.println("Statement 1");
* System.out.println("Statement 2");
* System.out.println("Statement 3");
* num = 1;
* PI = 3.14;
* }
*
* public void foo2() {
* int a; // OK, distance = 2
* int b; // OK, distance = 3
* int count = 0; // violation, distance = 4
*
* {
* System.out.println("Inside inner scope");
* a = 1;
* b = 2;
* count++;
* }
* }
* }
* </pre>
* <p>
* To configure the check to check final variables:
* </p>
* <pre>
* <module name="VariableDeclarationUsageDistance">
* <property name="ignoreFinal" value="false"/>
* </module>
* </pre>
* <p>Example:</p>
* <pre>
* public class Test {
*
* public void foo1() {
* int num; // violation, distance = 4
* final int PI; // violation, distance = 5
* System.out.println("Statement 1");
* System.out.println("Statement 2");
* System.out.println("Statement 3");
* num = 1;
* PI = 3.14;
* }
*
* public void foo2() {
* int a; // OK, used in different scope
* int b; // OK, used in different scope
* int count = 0; // OK, used in different scope
*
* {
* System.out.println("Inside inner scope");
* a = 1;
* b = 2;
* count++;
* }
* }
* }
* </pre>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code variable.declaration.usage.distance}
* </li>
* <li>
* {@code variable.declaration.usage.distance.extend}
* </li>
* </ul>
*
* @since 5.8
*/
@StatelessCheck
public class VariableDeclarationUsageDistanceCheck extends AbstractCheck {
/**
* Warning message key.
*/
public static final String MSG_KEY = "variable.declaration.usage.distance";
/**
* Warning message key.
*/
public static final String MSG_KEY_EXT = "variable.declaration.usage.distance.extend";
/**
* Default value of distance between declaration of variable and its first
* usage.
*/
private static final int DEFAULT_DISTANCE = 3;
/**
* Specify distance between declaration of variable and its first usage.
* Values should be greater than 0.
*/
private int allowedDistance = DEFAULT_DISTANCE;
/**
* Define RegExp to ignore distance calculation for variables listed in
* this pattern.
*/
private Pattern ignoreVariablePattern = Pattern.compile("");
/**
* Allow to calculate the distance between declaration of variable and its
* first usage in the different scopes.
*/
private boolean validateBetweenScopes;
/** Allow to ignore variables with a 'final' modifier. */
private boolean ignoreFinal = true;
/**
* Setter to specify distance between declaration of variable and its first usage.
* Values should be greater than 0.
*
* @param allowedDistance
* Allowed distance between declaration of variable and its first
* usage.
*/
public void setAllowedDistance(int allowedDistance) {
this.allowedDistance = allowedDistance;
}
/**
* Setter to define RegExp to ignore distance calculation for variables listed in this pattern.
*
* @param pattern a pattern.
*/
public void setIgnoreVariablePattern(Pattern pattern) {
ignoreVariablePattern = pattern;
}
/**
* Setter to allow to calculate the distance between declaration of
* variable and its first usage in the different scopes.
*
* @param validateBetweenScopes
* Defines if allow to calculate distance between declaration of
* variable and its first usage in different scopes or not.
*/
public void setValidateBetweenScopes(boolean validateBetweenScopes) {
this.validateBetweenScopes = validateBetweenScopes;
}
/**
* Setter to allow to ignore variables with a 'final' modifier.
*
* @param ignoreFinal
* Defines if ignore variables with 'final' modifier or not.
*/
public void setIgnoreFinal(boolean ignoreFinal) {
this.ignoreFinal = ignoreFinal;
}
@Override
public int[] getDefaultTokens() {
return getRequiredTokens();
}
@Override
public int[] getAcceptableTokens() {
return getRequiredTokens();
}
@Override
public int[] getRequiredTokens() {
return new int[] {TokenTypes.VARIABLE_DEF};
}
@Override
public void visitToken(DetailAST ast) {
final int parentType = ast.getParent().getType();
final DetailAST modifiers = ast.getFirstChild();
if (parentType != TokenTypes.OBJBLOCK
&& (!ignoreFinal || modifiers.findFirstToken(TokenTypes.FINAL) == null)) {
final DetailAST variable = ast.findFirstToken(TokenTypes.IDENT);
if (!isVariableMatchesIgnorePattern(variable.getText())) {
final DetailAST semicolonAst = ast.getNextSibling();
final Entry<DetailAST, Integer> entry;
if (validateBetweenScopes) {
entry = calculateDistanceBetweenScopes(semicolonAst, variable);
}
else {
entry = calculateDistanceInSingleScope(semicolonAst, variable);
}
final DetailAST variableUsageAst = entry.getKey();
final int dist = entry.getValue();
if (dist > allowedDistance
&& !isInitializationSequence(variableUsageAst, variable.getText())) {
if (ignoreFinal) {
log(ast, MSG_KEY_EXT, variable.getText(), dist, allowedDistance);
}
else {
log(ast, MSG_KEY, variable.getText(), dist, allowedDistance);
}
}
}
}
}
/**
* Get name of instance whose method is called.
*
* @param methodCallAst
* DetailAST of METHOD_CALL.
* @return name of instance.
*/
private static String getInstanceName(DetailAST methodCallAst) {
final String methodCallName =
FullIdent.createFullIdentBelow(methodCallAst).getText();
final int lastDotIndex = methodCallName.lastIndexOf('.');
String instanceName = "";
if (lastDotIndex != -1) {
instanceName = methodCallName.substring(0, lastDotIndex);
}
return instanceName;
}
/**
* Processes statements until usage of variable to detect sequence of
* initialization methods.
*
* @param variableUsageAst
* DetailAST of expression that uses variable named variableName.
* @param variableName
* name of considered variable.
* @return true if statements between declaration and usage of variable are
* initialization methods.
*/
private static boolean isInitializationSequence(
DetailAST variableUsageAst, String variableName) {
boolean result = true;
boolean isUsedVariableDeclarationFound = false;
DetailAST currentSiblingAst = variableUsageAst;
String initInstanceName = "";
while (result
&& !isUsedVariableDeclarationFound
&& currentSiblingAst != null) {
switch (currentSiblingAst.getType()) {
case TokenTypes.EXPR:
final DetailAST methodCallAst = currentSiblingAst.getFirstChild();
if (methodCallAst.getType() == TokenTypes.METHOD_CALL) {
final String instanceName =
getInstanceName(methodCallAst);
// method is called without instance
if (instanceName.isEmpty()) {
result = false;
}
// differs from previous instance
else if (!instanceName.equals(initInstanceName)) {
if (initInstanceName.isEmpty()) {
initInstanceName = instanceName;
}
else {
result = false;
}
}
}
else {
// is not method call
result = false;
}
break;
case TokenTypes.VARIABLE_DEF:
final String currentVariableName = currentSiblingAst
.findFirstToken(TokenTypes.IDENT).getText();
isUsedVariableDeclarationFound = variableName.equals(currentVariableName);
break;
case TokenTypes.SEMI:
break;
default:
result = false;
}
currentSiblingAst = currentSiblingAst.getPreviousSibling();
}
return result;
}
/**
* Calculates distance between declaration of variable and its first usage
* in single scope.
*
* @param semicolonAst
* Regular node of Ast which is checked for content of checking
* variable.
* @param variableIdentAst
* Variable which distance is calculated for.
* @return entry which contains expression with variable usage and distance.
*/
private static Entry<DetailAST, Integer> calculateDistanceInSingleScope(
DetailAST semicolonAst, DetailAST variableIdentAst) {
int dist = 0;
boolean firstUsageFound = false;
DetailAST currentAst = semicolonAst;
DetailAST variableUsageAst = null;
while (!firstUsageFound && currentAst != null
&& currentAst.getType() != TokenTypes.RCURLY) {
if (currentAst.getFirstChild() != null) {
if (isChild(currentAst, variableIdentAst)) {
dist = getDistToVariableUsageInChildNode(currentAst, variableIdentAst, dist);
variableUsageAst = currentAst;
firstUsageFound = true;
}
else if (currentAst.getType() != TokenTypes.VARIABLE_DEF) {
dist++;
}
}
currentAst = currentAst.getNextSibling();
}
// If variable wasn't used after its declaration, distance is 0.
if (!firstUsageFound) {
dist = 0;
}
return new SimpleEntry<>(variableUsageAst, dist);
}
/**
* Returns the distance to variable usage for in the child node.
*
* @param childNode child node.
* @param varIdent variable variable identifier.
* @param currentDistToVarUsage current distance to the variable usage.
* @return the distance to variable usage for in the child node.
*/
private static int getDistToVariableUsageInChildNode(DetailAST childNode, DetailAST varIdent,
int currentDistToVarUsage) {
DetailAST examineNode = childNode;
if (examineNode.getType() == TokenTypes.LABELED_STAT) {
examineNode = examineNode.getFirstChild().getNextSibling();
}
int resultDist = currentDistToVarUsage;
switch (examineNode.getType()) {
case TokenTypes.VARIABLE_DEF:
resultDist++;
break;
case TokenTypes.SLIST:
resultDist = 0;
break;
case TokenTypes.LITERAL_FOR:
case TokenTypes.LITERAL_WHILE:
case TokenTypes.LITERAL_DO:
case TokenTypes.LITERAL_IF:
case TokenTypes.LITERAL_SWITCH:
if (isVariableInOperatorExpr(examineNode, varIdent)) {
resultDist++;
}
else {
// variable usage is in inner scope
// reset counters, because we can't determine distance
resultDist = 0;
}
break;
default:
if (examineNode.findFirstToken(TokenTypes.SLIST) == null) {
resultDist++;
}
else {
resultDist = 0;
}
}
return resultDist;
}
/**
* Calculates distance between declaration of variable and its first usage
* in multiple scopes.
*
* @param ast
* Regular node of Ast which is checked for content of checking
* variable.
* @param variable
* Variable which distance is calculated for.
* @return entry which contains expression with variable usage and distance.
*/
private static Entry<DetailAST, Integer> calculateDistanceBetweenScopes(
DetailAST ast, DetailAST variable) {
int dist = 0;
DetailAST currentScopeAst = ast;
DetailAST variableUsageAst = null;
while (currentScopeAst != null) {
final Entry<List<DetailAST>, Integer> searchResult =
searchVariableUsageExpressions(variable, currentScopeAst);
currentScopeAst = null;
final List<DetailAST> variableUsageExpressions = searchResult.getKey();
dist += searchResult.getValue();
// If variable usage exists in a single scope, then look into
// this scope and count distance until variable usage.
if (variableUsageExpressions.size() == 1) {
final DetailAST blockWithVariableUsage = variableUsageExpressions
.get(0);
DetailAST exprWithVariableUsage = null;
switch (blockWithVariableUsage.getType()) {
case TokenTypes.VARIABLE_DEF:
case TokenTypes.EXPR:
dist++;
break;
case TokenTypes.LITERAL_FOR:
case TokenTypes.LITERAL_WHILE:
case TokenTypes.LITERAL_DO:
exprWithVariableUsage = getFirstNodeInsideForWhileDoWhileBlocks(
blockWithVariableUsage, variable);
break;
case TokenTypes.LITERAL_IF:
exprWithVariableUsage = getFirstNodeInsideIfBlock(
blockWithVariableUsage, variable);
break;
case TokenTypes.LITERAL_SWITCH:
exprWithVariableUsage = getFirstNodeInsideSwitchBlock(
blockWithVariableUsage, variable);
break;
case TokenTypes.LITERAL_TRY:
exprWithVariableUsage =
getFirstNodeInsideTryCatchFinallyBlocks(blockWithVariableUsage,
variable);
break;
default:
exprWithVariableUsage = blockWithVariableUsage.getFirstChild();
}
currentScopeAst = exprWithVariableUsage;
if (exprWithVariableUsage == null) {
variableUsageAst = blockWithVariableUsage;
}
else {
variableUsageAst = exprWithVariableUsage;
}
}
// If there's no any variable usage, then distance = 0.
else if (variableUsageExpressions.isEmpty()) {
variableUsageAst = null;
}
// If variable usage exists in different scopes, then distance =
// distance until variable first usage.
else {
dist++;
variableUsageAst = variableUsageExpressions.get(0);
}
}
return new SimpleEntry<>(variableUsageAst, dist);
}
/**
* Searches variable usages starting from specified statement.
*
* @param variableAst Variable that is used.
* @param statementAst DetailAST to start searching from.
* @return entry which contains list with found expressions that use the variable
* and distance from specified statement to first found expression.
*/
private static Entry<List<DetailAST>, Integer>
searchVariableUsageExpressions(final DetailAST variableAst, final DetailAST statementAst) {
final List<DetailAST> variableUsageExpressions = new ArrayList<>();
int distance = 0;
DetailAST currentStatementAst = statementAst;
while (currentStatementAst != null
&& currentStatementAst.getType() != TokenTypes.RCURLY) {
if (currentStatementAst.getFirstChild() != null) {
if (isChild(currentStatementAst, variableAst)) {
variableUsageExpressions.add(currentStatementAst);
}
// If expression doesn't contain variable and this variable
// hasn't been met yet, then distance + 1.
else if (variableUsageExpressions.isEmpty()
&& currentStatementAst.getType() != TokenTypes.VARIABLE_DEF) {
distance++;
}
}
currentStatementAst = currentStatementAst.getNextSibling();
}
return new SimpleEntry<>(variableUsageExpressions, distance);
}
/**
* Gets first Ast node inside FOR, WHILE or DO-WHILE blocks if variable
* usage is met only inside the block (not in its declaration!).
*
* @param block
* Ast node represents FOR, WHILE or DO-WHILE block.
* @param variable
* Variable which is checked for content in block.
* @return If variable usage is met only inside the block
* (not in its declaration!) then return the first Ast node
* of this block, otherwise - null.
*/
private static DetailAST getFirstNodeInsideForWhileDoWhileBlocks(
DetailAST block, DetailAST variable) {
DetailAST firstNodeInsideBlock = null;
if (!isVariableInOperatorExpr(block, variable)) {
final DetailAST currentNode;
// Find currentNode for DO-WHILE block.
if (block.getType() == TokenTypes.LITERAL_DO) {
currentNode = block.getFirstChild();
}
// Find currentNode for FOR or WHILE block.
else {
// Looking for RPAREN ( ')' ) token to mark the end of operator
// expression.
currentNode = block.findFirstToken(TokenTypes.RPAREN).getNextSibling();
}
final int currentNodeType = currentNode.getType();
if (currentNodeType == TokenTypes.SLIST) {
firstNodeInsideBlock = currentNode.getFirstChild();
}
else if (currentNodeType != TokenTypes.EXPR) {
firstNodeInsideBlock = currentNode;
}
}
return firstNodeInsideBlock;
}
/**
* Gets first Ast node inside IF block if variable usage is met
* only inside the block (not in its declaration!).
*
* @param block
* Ast node represents IF block.
* @param variable
* Variable which is checked for content in block.
* @return If variable usage is met only inside the block
* (not in its declaration!) then return the first Ast node
* of this block, otherwise - null.
*/
private static DetailAST getFirstNodeInsideIfBlock(
DetailAST block, DetailAST variable) {
DetailAST firstNodeInsideBlock = null;
if (!isVariableInOperatorExpr(block, variable)) {
DetailAST currentNode = block.getLastChild();
final List<DetailAST> variableUsageExpressions =
new ArrayList<>();
while (currentNode != null
&& currentNode.getType() == TokenTypes.LITERAL_ELSE) {
final DetailAST previousNode =
currentNode.getPreviousSibling();
// Checking variable usage inside IF block.
if (isChild(previousNode, variable)) {
variableUsageExpressions.add(previousNode);
}
// Looking into ELSE block, get its first child and analyze it.
currentNode = currentNode.getFirstChild();
if (currentNode.getType() == TokenTypes.LITERAL_IF) {
currentNode = currentNode.getLastChild();
}
else if (isChild(currentNode, variable)) {
variableUsageExpressions.add(currentNode);
currentNode = null;
}
}
// If IF block doesn't include ELSE then analyze variable usage
// only inside IF block.
if (currentNode != null
&& isChild(currentNode, variable)) {
variableUsageExpressions.add(currentNode);
}
// If variable usage exists in several related blocks, then
// firstNodeInsideBlock = null, otherwise if variable usage exists
// only inside one block, then get node from
// variableUsageExpressions.
if (variableUsageExpressions.size() == 1) {
firstNodeInsideBlock = variableUsageExpressions.get(0);
}
}
return firstNodeInsideBlock;
}
/**
* Gets first Ast node inside SWITCH block if variable usage is met
* only inside the block (not in its declaration!).
*
* @param block
* Ast node represents SWITCH block.
* @param variable
* Variable which is checked for content in block.
* @return If variable usage is met only inside the block
* (not in its declaration!) then return the first Ast node
* of this block, otherwise - null.
*/
private static DetailAST getFirstNodeInsideSwitchBlock(
DetailAST block, DetailAST variable) {
final DetailAST currentNode = getFirstCaseGroupOrSwitchRule(block);
final List<DetailAST> variableUsageExpressions =
new ArrayList<>();
// Checking variable usage inside all CASE_GROUP and SWITCH_RULE ast's.
TokenUtil.forEachChild(block, currentNode.getType(), node -> {
final DetailAST lastNodeInCaseGroup =
node.getLastChild();
if (isChild(lastNodeInCaseGroup, variable)) {
variableUsageExpressions.add(lastNodeInCaseGroup);
}
});
// If variable usage exists in several related blocks, then
// firstNodeInsideBlock = null, otherwise if variable usage exists
// only inside one block, then get node from
// variableUsageExpressions.
DetailAST firstNodeInsideBlock = null;
if (variableUsageExpressions.size() == 1) {
firstNodeInsideBlock = variableUsageExpressions.get(0);
}
return firstNodeInsideBlock;
}
/**
* Helper method for getFirstNodeInsideSwitchBlock to return the first CASE_GROUP or
* SWITCH_RULE ast.
*
* @param block the switch block to check.
* @return DetailAST of the first CASE_GROUP or SWITCH_RULE.
*/
private static DetailAST getFirstCaseGroupOrSwitchRule(DetailAST block) {
return Optional.ofNullable(block.findFirstToken(TokenTypes.CASE_GROUP))
.orElse(block.findFirstToken(TokenTypes.SWITCH_RULE));
}
/**
* Gets first Ast node inside TRY-CATCH-FINALLY blocks if variable usage is
* met only inside the block (not in its declaration!).
*
* @param block
* Ast node represents TRY-CATCH-FINALLY block.
* @param variable
* Variable which is checked for content in block.
* @return If variable usage is met only inside the block
* (not in its declaration!) then return the first Ast node
* of this block, otherwise - null.
*/
private static DetailAST getFirstNodeInsideTryCatchFinallyBlocks(
DetailAST block, DetailAST variable) {
DetailAST currentNode = block.getFirstChild();
final List<DetailAST> variableUsageExpressions =
new ArrayList<>();
// Checking variable usage inside TRY block.
if (isChild(currentNode, variable)) {
variableUsageExpressions.add(currentNode);
}
// Switch on CATCH block.
currentNode = currentNode.getNextSibling();
// Checking variable usage inside all CATCH blocks.
while (currentNode != null
&& currentNode.getType() == TokenTypes.LITERAL_CATCH) {
final DetailAST catchBlock = currentNode.getLastChild();
if (isChild(catchBlock, variable)) {
variableUsageExpressions.add(catchBlock);
}
currentNode = currentNode.getNextSibling();
}
// Checking variable usage inside FINALLY block.
if (currentNode != null) {
final DetailAST finalBlock = currentNode.getLastChild();
if (isChild(finalBlock, variable)) {
variableUsageExpressions.add(finalBlock);
}
}
DetailAST variableUsageNode = null;
// If variable usage exists in several related blocks, then
// firstNodeInsideBlock = null, otherwise if variable usage exists
// only inside one block, then get node from
// variableUsageExpressions.
if (variableUsageExpressions.size() == 1) {
variableUsageNode = variableUsageExpressions.get(0).getFirstChild();
}
return variableUsageNode;
}
/**
* Checks if variable is in operator declaration. For instance:
* <pre>
* boolean b = true;
* if (b) {...}
* </pre>
* Variable 'b' is in declaration of operator IF.
*
* @param operator
* Ast node which represents operator.
* @param variable
* Variable which is checked for content in operator.
* @return true if operator contains variable in its declaration, otherwise
* - false.
*/
private static boolean isVariableInOperatorExpr(
DetailAST operator, DetailAST variable) {
boolean isVarInOperatorDeclaration = false;
final DetailAST openingBracket =
operator.findFirstToken(TokenTypes.LPAREN);
// Get EXPR between brackets
DetailAST exprBetweenBrackets = openingBracket.getNextSibling();
// Look if variable is in operator expression
while (exprBetweenBrackets.getType() != TokenTypes.RPAREN) {
if (isChild(exprBetweenBrackets, variable)) {
isVarInOperatorDeclaration = true;
break;
}
exprBetweenBrackets = exprBetweenBrackets.getNextSibling();
}
// Variable may be met in ELSE declaration
// So, check variable usage in these declarations.
if (!isVarInOperatorDeclaration && operator.getType() == TokenTypes.LITERAL_IF) {
final DetailAST elseBlock = operator.getLastChild();
if (elseBlock.getType() == TokenTypes.LITERAL_ELSE) {
// Get IF followed by ELSE
final DetailAST firstNodeInsideElseBlock = elseBlock.getFirstChild();
if (firstNodeInsideElseBlock.getType() == TokenTypes.LITERAL_IF) {
isVarInOperatorDeclaration =
isVariableInOperatorExpr(firstNodeInsideElseBlock, variable);
}
}
}
return isVarInOperatorDeclaration;
}
/**
* Checks if Ast node contains given element.
*
* @param parent
* Node of AST.
* @param ast
* Ast element which is checked for content in Ast node.
* @return true if Ast element was found in Ast node, otherwise - false.
*/
private static boolean isChild(DetailAST parent, DetailAST ast) {
boolean isChild = false;
DetailAST curNode = parent.getFirstChild();
while (curNode != null) {
if (curNode.getType() == ast.getType() && curNode.getText().equals(ast.getText())) {
isChild = true;
break;
}
DetailAST toVisit = curNode.getFirstChild();
while (toVisit == null) {
toVisit = curNode.getNextSibling();
curNode = curNode.getParent();
if (curNode == parent) {
break;
}
}
curNode = toVisit;
}
return isChild;
}
/**
* Checks if entrance variable is contained in ignored pattern.
*
* @param variable
* Variable which is checked for content in ignored pattern.
* @return true if variable was found, otherwise - false.
*/
private boolean isVariableMatchesIgnorePattern(String variable) {
final Matcher matcher = ignoreVariablePattern.matcher(variable);
return matcher.matches();
}
}