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backend/app/dataset/rules/java/logic_operator.py

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+"""AST-level logical operator misuse injection for Java using javalang."""
+
+from typing import Optional
+
+import javalang
+
+from app.dataset.rules.base import Mutation, MutationRule
+
+
+class JavaLogicOperatorRule(MutationRule):
+    """Swap `&&` with `||` in a boolean expression.
+
+    Uses `javalang` to locate a binary operation with `&&` and replaces the
+    operator with `||`.
+    """
+
+    name = "java_logic_operator"
+    language = "java"
+    defect_type = "logic_operator_misuse"
+
+    def detect_and_mutate(self, source: str, filename: str = "") -> Optional[Mutation]:
+        try:
+            tree = javalang.parse.parse(source)
+        except Exception:
+            return None
+
+        for path, node in tree:
+            if not isinstance(node, javalang.tree.BinaryOperation):
+                continue
+            if node.operator != "&&":
+                continue
+            return_statement = next((n for n in path if isinstance(n, javalang.tree.ReturnStatement)), None)
+            pos = return_statement.position if return_statement else node.position
+            if not pos:
+                continue
+            lines = source.splitlines(keepends=True)
+            line_no = pos.line
+            line = lines[line_no - 1]
+            mutated_line = line.replace("&&", "||", 1)
+            if mutated_line == line:
+                continue
+            mutated = "".join(lines[:line_no - 1] + [mutated_line] + lines[line_no:])
+            return Mutation(
+                defect_type=self.defect_type,
+                language=self.language,
+                line_start=line_no,
+                line_end=line_no,
+                mutated_source=mutated,
+                reference_fix="Restore `&&` for correct conjunction semantics.",
+                description="Replaced boolean `&&` with `||`.",
+            )
+        return None