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Use explicit this.field and this.method()

org.openrewrite.staticanalysis.ExplicitThis

Add explicit 'this.' prefix to field and method access.

Recipe source​

GitHub: ExplicitThis.java, Issue Tracker, Maven Central

This recipe is available under the Moderne Source Available License.

Example​

Before​
import java.util.function.Consumer;

class Parent {
    private String parentField;

    Parent(String value) {
        parentField = value;
    }
}

class Test extends Parent {
    private String value;
    private String field;
    private String field1;
    private String field2;
    private static String staticField;
    private String alreadyPrefixed;

    private String fieldInit1 = "initial";
    private String fieldInit2 = field1;
    private String fieldInit3 = field1 + field2;

    private static String staticFieldInit = staticField;

    static {
        staticField = "static initializer";
        staticHelper();
    }

    {
        field = "instance initializer";
        field1 = field2;
    }

    Test(String value) {
        super(value);
        // Shadowed parameter: looks like a bug but replacing would change semantics
        value = value;
        field = "constructor";
        field1 = field2;
    }

    Test() {
        this("default");
    }

    void instanceMethod(String parameter) {
        field = "value";
        field1 = field2;
        helper();
        staticField = "static context";
        staticMethod();

        String localVariable = parameter;
        String result = parameter + localVariable;

        this.alreadyPrefixed = "already has this";
        this.alreadyPrefixedMethod();
        super.toString();

        Consumer<String> lambda = s -> {
            field = s;
            field1 = field2;
        };

        Runnable runnable = () -> field = "lambda";
    }

    static void staticMethod() {
        staticField = "static context";
        staticHelper();
    }

    // Shadowed parameter: looks like a bug but replacing would change semantics
    void setField(String field) {
        field = field;
    }

    void helper() {}
    void alreadyPrefixedMethod() {}
    static void staticHelper() {}

    class Inner {
        private String innerField;

        void method() {
            innerField = "inner";
            field = "outer";
            Consumer<String> lambda = s -> {
                innerField = s;
                field = s;
            };
        }

        class Nested {
            private String nestedField;

            void method() {
                nestedField = "nested";
                innerField = "inner";
                field = "outer";
            }
        }
    }

    static class StaticNested {
        private String nestedField;
        private static String nestedStaticField;

        void method() {
            nestedField = "nested";
            nestedStaticField = "static";
            staticField = "outer static";
        }

        static void staticMethod() {
            nestedStaticField = "static";
            staticField = "outer static";
        }
    }

    void anonymousClassExample() {
        Runnable r = new Runnable() {
            private String anonymousField = "anonymous";

            @Override
            public void run() {
                field = "outer";
                String local = anonymousField;
            }
        };
    }
}
After​
import java.util.function.Consumer;

class Parent {
    private String parentField;

    Parent(String value) {
        this.parentField = value;
    }
}

class Test extends Parent {
    private String value;
    private String field;
    private String field1;
    private String field2;
    private static String staticField;
    private String alreadyPrefixed;

    private String fieldInit1 = "initial";
    private String fieldInit2 = this.field1;
    private String fieldInit3 = this.field1 + this.field2;

    private static String staticFieldInit = staticField;

    static {
        staticField = "static initializer";
        staticHelper();
    }

    {
        this.field = "instance initializer";
        this.field1 = this.field2;
    }

    Test(String value) {
        super(value);
        // Shadowed parameter: looks like a bug but replacing would change semantics
        value = value;
        this.field = "constructor";
        this.field1 = this.field2;
    }

    Test() {
        this("default");
    }

    void instanceMethod(String parameter) {
        this.field = "value";
        this.field1 = this.field2;
        this.helper();
        staticField = "static context";
        staticMethod();

        String localVariable = parameter;
        String result = parameter + localVariable;

        this.alreadyPrefixed = "already has this";
        this.alreadyPrefixedMethod();
        super.toString();

        Consumer<String> lambda = s -> {
            this.field = s;
            this.field1 = this.field2;
        };

        Runnable runnable = () -> this.field = "lambda";
    }

    static void staticMethod() {
        staticField = "static context";
        staticHelper();
    }

    // Shadowed parameter: looks like a bug but replacing would change semantics
    void setField(String field) {
        field = field;
    }

    void helper() {}
    void alreadyPrefixedMethod() {}
    static void staticHelper() {}

    class Inner {
        private String innerField;

        void method() {
            this.innerField = "inner";
            Test.this.field = "outer";
            Consumer<String> lambda = s -> {
                this.innerField = s;
                Test.this.field = s;
            };
        }

        class Nested {
            private String nestedField;

            void method() {
                this.nestedField = "nested";
                Inner.this.innerField = "inner";
                Test.this.field = "outer";
            }
        }
    }

    static class StaticNested {
        private String nestedField;
        private static String nestedStaticField;

        void method() {
            this.nestedField = "nested";
            nestedStaticField = "static";
            staticField = "outer static";
        }

        static void staticMethod() {
            nestedStaticField = "static";
            staticField = "outer static";
        }
    }

    void anonymousClassExample() {
        Runnable r = new Runnable() {
            private String anonymousField = "anonymous";

            @Override
            public void run() {
                Test.this.field = "outer";
                String local = this.anonymousField;
            }
        };
    }
}

Usage​

This recipe has no required configuration options. It can be activated by adding a dependency on `org.openrewrite.recipe:rewrite-static-analysis` in your build file or by running a shell command (in which case no build changes are needed):

  1. Add the following to your build.gradle file:
    build.gradle
    plugins {
        id("org.openrewrite.rewrite") version("latest.release")
    }

    rewrite {
        activeRecipe("org.openrewrite.staticanalysis.ExplicitThis")
        setExportDatatables(true)
    }

    repositories {
        mavenCentral()
    }

    dependencies {
        rewrite("org.openrewrite.recipe:rewrite-static-analysis:2.31.0")
    }
  2. Run gradle rewriteRun to run the recipe.

See how this recipe works across multiple open-source repositories​

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Data Tables​

Source files that had results​

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column NameDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changesIn a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.