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Anmol202005Anmol202005
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Issue #33: FinalLocalVariable recipe created
1 parent d247386 commit 3da3b1e

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12 files changed

+731
-90
lines changed

12 files changed

+731
-90
lines changed

‎src/main/java/org/checkstyle/autofix/PositionHelper.java‎

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///////////////////////////////////////////////////////////////////////////////////////////////
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// checkstyle-openrewrite-recipes: Automatically fix Checkstyle violations with OpenRewrite.
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// Copyright (C) 2025 The Checkstyle OpenRewrite Recipes Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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///////////////////////////////////////////////////////////////////////////////////////////////
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package org.checkstyle.autofix;
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import java.util.concurrent.CancellationException;
21+
import java.util.function.Function;
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23+
import org.openrewrite.Cursor;
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import org.openrewrite.PrintOutputCapture;
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import org.openrewrite.TreeVisitor;
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import org.openrewrite.internal.RecipeRunException;
27+
import org.openrewrite.java.tree.J;
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public final class PositionHelper {
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private PositionHelper() {
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// Utility class
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}
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public static int computeLinePosition(J tree, J targetElement, Cursor cursor) {
36+
return computePosition(tree, targetElement, cursor,
37+
out -> 1 + Math.toIntExact(out.chars().filter(chr -> chr == '\n').count()));
38+
}
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40+
public static int computeColumnPosition(J tree, J targetElement, Cursor cursor) {
41+
return computePosition(tree, targetElement, cursor, out -> {
42+
int column = calculateColumnOffset(out);
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if (targetElement instanceof J.Literal literal
44+
&& literal.getValue() instanceof Number
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&& literal.getValueSource() != null
46+
&& literal.getValueSource().matches("^[+-].*")) {
47+
column++;
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}
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return column;
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});
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}
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private static int computePosition(
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J tree,
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J targetElement,
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Cursor cursor,
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Function<String, Integer> positionCalculator
58+
) {
59+
final TreeVisitor<?, PrintOutputCapture<TreeVisitor<?, ?>>> printer =
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tree.printer(cursor);
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final PrintOutputCapture<TreeVisitor<?, ?>> capture =
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new PrintOutputCapture<>(printer) {
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@Override
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public PrintOutputCapture<TreeVisitor<?, ?>> append(String text) {
66+
if (targetElement.isScope(getContext().getCursor().getValue())) {
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super.append(targetElement.getPrefix().getWhitespace());
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throw new CancellationException();
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}
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return super.append(text);
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}
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};
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final int result;
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try {
76+
printer.visit(tree, capture, cursor.getParentOrThrow());
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throw new IllegalStateException("Target element: " + targetElement
78+
+ ", not found in the syntax tree.");
79+
}
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catch (CancellationException exception) {
81+
result = positionCalculator.apply(capture.getOut());
82+
}
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catch (RecipeRunException exception) {
84+
if (exception.getCause() instanceof CancellationException) {
85+
result = positionCalculator.apply(capture.getOut());
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}
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else {
88+
throw exception;
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}
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}
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return result;
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}
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private static int calculateColumnOffset(String out) {
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final int lineBreakIndex = out.lastIndexOf('\n');
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final int result;
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if (lineBreakIndex == -1) {
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result = out.length();
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}
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else {
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result = out.length() - lineBreakIndex;
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}
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return result;
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}
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}

‎src/main/java/org/checkstyle/autofix/recipe/FinalLocalVariable.java‎

Lines changed: 111 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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1+
///////////////////////////////////////////////////////////////////////////////////////////////
2+
// checkstyle-openrewrite-recipes: Automatically fix Checkstyle violations with OpenRewrite.
3+
// Copyright (C) 2025 The Checkstyle OpenRewrite Recipes Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
9+
// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
12+
// distributed under the License is distributed on an "AS IS" BASIS,
13+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14+
// See the License for the specific language governing permissions and
15+
// limitations under the License.
16+
///////////////////////////////////////////////////////////////////////////////////////////////
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package org.checkstyle.autofix.recipe;
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import java.nio.file.Path;
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import java.util.ArrayList;
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import java.util.List;
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24+
import org.checkstyle.autofix.PositionHelper;
25+
import org.checkstyle.autofix.parser.CheckstyleViolation;
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import org.openrewrite.ExecutionContext;
27+
import org.openrewrite.Recipe;
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import org.openrewrite.Tree;
29+
import org.openrewrite.TreeVisitor;
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import org.openrewrite.java.JavaIsoVisitor;
31+
import org.openrewrite.java.tree.J;
32+
import org.openrewrite.java.tree.Space;
33+
import org.openrewrite.marker.Markers;
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/**
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* Fixes Checkstyle FinalLocalVariable violations by adding 'final' modifier to local variables
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* that are never reassigned.
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*/
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public class FinalLocalVariable extends Recipe {
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private final List<CheckstyleViolation> violations;
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public FinalLocalVariable(List<CheckstyleViolation> violations) {
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this.violations = violations;
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}
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@Override
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public String getDisplayName() {
49+
return "FinalLocalVariable recipe";
50+
}
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@Override
53+
public String getDescription() {
54+
return "Adds 'final' modifier to local variables that never have their values changed.";
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}
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57+
@Override
58+
public TreeVisitor<?, ExecutionContext> getVisitor() {
59+
return new LocalVariableVisitor();
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}
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private final class LocalVariableVisitor extends JavaIsoVisitor<ExecutionContext> {
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private Path sourcePath;
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@Override
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public J.CompilationUnit visitCompilationUnit(J.CompilationUnit cu, ExecutionContext ctx) {
68+
this.sourcePath = cu.getSourcePath();
69+
return super.visitCompilationUnit(cu, ctx);
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}
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@Override
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public J.VariableDeclarations visitVariableDeclarations(
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J.VariableDeclarations multiVariable, ExecutionContext ctx) {
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J.VariableDeclarations declarations = super.visitVariableDeclarations(multiVariable,
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ctx);
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if (!(getCursor().getParentTreeCursor().getValue() instanceof J.ClassDeclaration)
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&& declarations.getVariables().size() == 1
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&& declarations.getTypeExpression() != null
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&& !declarations.hasModifier(J.Modifier.Type.Final)) {
83+
final J.VariableDeclarations.NamedVariable variable = declarations
84+
.getVariables().get(0);
85+
if (isAtViolationLocation(variable)) {
86+
final List<J.Modifier> modifiers = new ArrayList<>();
87+
modifiers.add(new J.Modifier(Tree.randomId(), Space.EMPTY,
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Markers.EMPTY, null, J.Modifier.Type.Final, new ArrayList<>()));
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modifiers.addAll(declarations.getModifiers());
90+
declarations = declarations.withModifiers(modifiers)
91+
.withTypeExpression(declarations.getTypeExpression()
92+
.withPrefix(Space.SINGLE_SPACE));
93+
}
94+
}
95+
return declarations;
96+
}
97+
98+
private boolean isAtViolationLocation(J.VariableDeclarations.NamedVariable literal) {
99+
final J.CompilationUnit cursor = getCursor().firstEnclosing(J.CompilationUnit.class);
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final int line = PositionHelper.computeLinePosition(cursor, literal, getCursor());
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final int column = PositionHelper.computeColumnPosition(cursor, literal, getCursor());
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return violations.stream().anyMatch(violation -> {
105+
return violation.getLine() == line
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&& violation.getColumn() == column
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&& Path.of(violation.getFileName()).equals(sourcePath);
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});
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}
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}
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}

‎src/main/java/org/checkstyle/autofix/recipe/UpperEll.java‎

Lines changed: 3 additions & 90 deletions
Original file line numberDiff line numberDiff line change
@@ -19,16 +19,12 @@
1919

2020
import java.nio.file.Path;
2121
import java.util.List;
22-
import java.util.concurrent.CancellationException;
23-
import java.util.function.Function;
2422

23+
import org.checkstyle.autofix.PositionHelper;
2524
import org.checkstyle.autofix.parser.CheckstyleViolation;
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import org.openrewrite.Cursor;
2725
import org.openrewrite.ExecutionContext;
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import org.openrewrite.PrintOutputCapture;
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import org.openrewrite.Recipe;
3027
import org.openrewrite.TreeVisitor;
31-
import org.openrewrite.internal.RecipeRunException;
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import org.openrewrite.java.JavaIsoVisitor;
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import org.openrewrite.java.tree.J;
3430
import org.openrewrite.java.tree.JavaType;
@@ -93,8 +89,8 @@ && isAtViolationLocation(result)) {
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private boolean isAtViolationLocation(J.Literal literal) {
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final J.CompilationUnit cursor = getCursor().firstEnclosing(J.CompilationUnit.class);
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96-
final int line = computeLinePosition(cursor, literal, getCursor());
97-
final int column = computeColumnPosition(cursor, literal, getCursor());
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final int line = PositionHelper.computeLinePosition(cursor, literal, getCursor());
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final int column = PositionHelper.computeColumnPosition(cursor, literal, getCursor());
9894

9995
return violations.stream().anyMatch(violation -> {
10096
final Path absolutePath = Path.of(violation.getFileName()).toAbsolutePath();
@@ -103,88 +99,5 @@ private boolean isAtViolationLocation(J.Literal literal) {
10399
&& absolutePath.equals(sourcePath);
104100
});
105101
}
106-
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/**
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* Computes the position of a target element within a syntax tree using position calculator.
109-
* This method traverses the given syntax tree and captures the printed output until the
110-
* target element is encountered. When the target is found, a CancellationException
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* is thrown to interrupt traversal, and the captured output is passed to the provided
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* positionCalculator to compute the position.
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*
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* @param tree the root of the syntax tree to traverse
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* @param targetElement the element whose position is to be computed
116-
* @param cursor the current cursor in the tree traversal
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* @param positionCalculator a function to compute the position from the printed output
118-
* @return the computed position of the target element
119-
* @throws IllegalStateException if the target element is not found in the tree
120-
* @throws RecipeRunException if an error occurs during traversal
121-
*/
122-
private int computePosition(
123-
J tree,
124-
J targetElement,
125-
Cursor cursor,
126-
Function<String, Integer> positionCalculator
127-
) {
128-
final TreeVisitor<?, PrintOutputCapture<TreeVisitor<?, ?>>> printer =
129-
tree.printer(cursor);
130-
131-
final PrintOutputCapture<TreeVisitor<?, ?>> capture =
132-
new PrintOutputCapture<>(printer) {
133-
@Override
134-
public PrintOutputCapture<TreeVisitor<?, ?>> append(String text) {
135-
if (targetElement.isScope(getContext().getCursor().getValue())) {
136-
super.append(targetElement.getPrefix().getWhitespace());
137-
throw new CancellationException();
138-
}
139-
return super.append(text);
140-
}
141-
};
142-
143-
final int result;
144-
try {
145-
printer.visit(tree, capture, cursor.getParentOrThrow());
146-
throw new IllegalStateException("Target element: " + targetElement
147-
+ ", not found in the syntax tree.");
148-
}
149-
catch (CancellationException exception) {
150-
result = positionCalculator.apply(capture.getOut());
151-
}
152-
catch (RecipeRunException exception) {
153-
if (exception.getCause() instanceof CancellationException) {
154-
result = positionCalculator.apply(capture.getOut());
155-
}
156-
else {
157-
throw exception;
158-
}
159-
}
160-
return result;
161-
}
162-
163-
private int computeLinePosition(J tree, J targetElement, Cursor cursor) {
164-
return computePosition(tree, targetElement, cursor,
165-
out -> 1 + Math.toIntExact(out.chars().filter(chr -> chr == '\n').count()));
166-
}
167-
168-
private int computeColumnPosition(J tree, J targetElement, Cursor cursor) {
169-
return computePosition(tree, targetElement, cursor, out -> {
170-
int column = calculateColumnOffset(out);
171-
if (((J.Literal) targetElement).getValueSource().matches("^[+-].*")) {
172-
column++;
173-
}
174-
return column;
175-
});
176-
}
177-
178-
private int calculateColumnOffset(String out) {
179-
final int lineBreakIndex = out.lastIndexOf('\n');
180-
final int result;
181-
if (lineBreakIndex == -1) {
182-
result = out.length();
183-
}
184-
else {
185-
result = out.length() - lineBreakIndex;
186-
}
187-
return result;
188-
}
189102
}
190103
}

‎src/test/java/org/checkstyle/autofix/recipe/FinalLocalVariableTest.java‎

Lines changed: 60 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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///////////////////////////////////////////////////////////////////////////////////////////////
2+
// checkstyle-openrewrite-recipes: Automatically fix Checkstyle violations with OpenRewrite.
3+
// Copyright (C) 2025 The Checkstyle OpenRewrite Recipes Authors
4+
//
5+
// Licensed under the Apache License, Version 2.0 (the "License");
6+
// you may not use this file except in compliance with the License.
7+
// You may obtain a copy of the License at
8+
//
9+
// http://www.apache.org/licenses/LICENSE-2.0
10+
//
11+
// Unless required by applicable law or agreed to in writing, software
12+
// distributed under the License is distributed on an "AS IS" BASIS,
13+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14+
// See the License for the specific language governing permissions and
15+
// limitations under the License.
16+
///////////////////////////////////////////////////////////////////////////////////////////////
17+
18+
package org.checkstyle.autofix.recipe;
19+
20+
import java.util.List;
21+
22+
import org.checkstyle.autofix.parser.CheckConfiguration;
23+
import org.checkstyle.autofix.parser.CheckstyleViolation;
24+
import org.junit.jupiter.api.Test;
25+
import org.openrewrite.Recipe;
26+
27+
public class FinalLocalVariableTest extends AbstractRecipeTestSupport {
28+
29+
@Override
30+
protected String getSubpackage() {
31+
return "finallocalvariable";
32+
}
33+
34+
@Override
35+
protected Recipe createRecipe(List<CheckstyleViolation> violations, CheckConfiguration config) {
36+
37+
return new FinalLocalVariable(violations);
38+
}
39+
40+
@Test
41+
void singleLocalTest() throws Exception {
42+
verify("SingleLocalTest");
43+
}
44+
45+
@Test
46+
void classFieldTest() throws Exception {
47+
verify("ClassFieldTest");
48+
}
49+
50+
@Test
51+
void edgeCaseTest() throws Exception {
52+
verify("EdgeCaseTest");
53+
}
54+
55+
@Test
56+
void enhancedForLoop() throws Exception {
57+
verify("EnhancedForLoop");
58+
}
59+
60+
}

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