chore(java): add a method to copy a java method and rename it

.gitignore

@@ -110,6 +110,7 @@ venv.bak/
 .vscode/
 .settings/
 .project
+.idea/
 
 # synthtool artifacts
 working_repo/

synthtool/languages/java.py

@@ -572,3 +572,143 @@ class Example {
         for line in lines:
             # print(line)
             fp.write(line)
+
+
+def copy_and_rename_method(filename: str, signature: str, before: str, after: str):
+    """Helper to make a copy an entire method and rename it.
+
+    Goes line-by-line to detect the start of the block. Determines
+    the end of the block by a closing brace at the same indentation
+    level. This requires the file to be correctly formatted.
+    The method is copied over and renamed in the method signature.
+    The calls to both methods are separate and unaffected.
+
+    Example: consider the following class:
+
+        class Example {
+            public void main(String[] args) {
+                System.out.println("Hello World");
+            }
+
+            public String foo() {
+                return "bar";
+            }
+        }
+
+    To copy and rename the `main` method above, use:
+
+    copy_and_rename_method('path/to/file', 'public void main(String[] args)',
+        'main', 'foo1')
+
+    Args:
+        filename (str): Path to source file
+        signature (str): Full signature of the method to remove. Example:
+            `public void main(String[] args)`.
+        before (str): name of the method to be copied
+        after (str): new name of the copied method
+    """
+    lines = []
+    method = []
+    leading_regex = None
+    with open(filename, "r") as fp:
+        line = fp.readline()
+        while line:
+            # for each line, try to find the matching
+            regex = re.compile("(\\s*)" + re.escape(signature) + ".*")
+            match = regex.match(line)
+            if match:
+                leading_regex = re.compile(match.group(1) + "}")
+                lines.append(line)
+                method.append(line.replace(before, after))
+                line = fp.readline()
+                continue
+
+            lines.append(line)
+            # not in a ignore block - preserve the line
+            if leading_regex:
+                method.append(line)
+            else:
+                line = fp.readline()
+                continue
+
+            # detect the closing tag based on the leading spaces
+            match = leading_regex.match(line)
+            if match:
+                # block is closed, resume capturing content
+                leading_regex = None
+                lines.append("\n")
+                lines.extend(method)
+
+            line = fp.readline()
+
+    with open(filename, "w") as fp:
+        for line in lines:
+            # print(line)
+            fp.write(line)
+
+
+def deprecate_method(filename: str, signature: str, alternative: str):
+    """Helper to deprecate a method.
+
+        Goes line-by-line to detect the start of the block.
+        Then adds the deprecation comment before the method signature.
+        The @Deprecation annotation is also added.
+
+        Example: consider the following class:
+
+            class Example {
+                public void main(String[] args) {
+                    System.out.println("Hello World");
+                }
+
+                public String foo() {
+                    return "bar";
+                }
+            }
+
+        To deprecate the `main` method 6above, use:
+
+        deprecate_method('path/to/file', 'public void main(String[] args)',
+            DEPRECATION_WARNING.format(new_method="foo"))
+
+    Args:
+        filename (str): Path to source file
+        signature (str): Full signature of the method to remove. Example:
+            `public void main(String[] args)`.
+        alternative: DEPRECATION WARNING: multiline javadoc comment with user
+            specified leading open/close comment tags
+    """
+    lines: List[str] = []
+    annotations: List[str] = []
+    with open(filename, "r") as fp:
+        line = fp.readline()
+        while line:
+            # for each line, try to find the matching
+            regex = re.compile("(\\s*)" + re.escape(signature) + ".*")
+            match = regex.match(line)
+            if match:
+                last_line = lines.pop()
+                if "*/" in last_line:
+                    alternative = "\n".join(alternative.splitlines()[1:])
+                    lines.extend(alternative)
+                elif "@" in last_line:
+                    while "@" in last_line:
+                        if "@Deprecated" not in last_line:
+                            annotations.insert(0, last_line)
+                        last_line = lines.pop()
+                    if "*/" in last_line:
+                        alternative = "\n".join(alternative.splitlines()[1:])
+                    lines.extend(alternative)
+                    lines.extend(annotations)
+                else:
+                    lines.extend(last_line)
+                    lines.extend(alternative)
+                lines.append("@Deprecated\n")
+            lines.append(line)
+            line = fp.readline()
+
+    with open(filename, "w") as fp:
+        for line in lines:
+            # print(line)
+            fp.write(line)
+    format_code("/".join(filename.split("/")[:-1]))

tests/test_language_java.py

@@ -120,6 +120,58 @@ def test_remove_method():
         )
 
 
+def test_copy_and_rename_method():
+    with tempfile.TemporaryDirectory() as tempdir:
+        shutil.copyfile(
+            "tests/testdata/SampleClass.java", tempdir + "/SampleClass.java"
+        )
+
+        java.copy_and_rename_method(
+            tempdir + "/SampleClass.java", "public static void foo()", "foo", "foobar"
+        )
+        java.copy_and_rename_method(
+            tempdir + "/SampleClass.java", "public void asdf()", "asdf", "xyz"
+        )
+        assert_matches_golden(
+            "tests/testdata/SampleCopyMethodGolden.java", tempdir + "/SampleClass.java"
+        )
+
+
+def test_deprecate_method():
+    with tempfile.TemporaryDirectory() as tempdir:
+        shutil.copyfile(
+            "tests/testdata/SampleClass.java", tempdir + "/SampleClass.java"
+        )
+        DEPRECATION_WARNING = """ /*
+   * @deprecated This method will be removed in the next major version.
+   * Use {{@link #{new_method}()}} instead
+   */
+    """
+        ADDITIONAL_COMMENT = """ /*
+   * {new_method} has the same functionality as foobar.
+   */
+   """
+        java.copy_and_rename_method(
+            tempdir + "/SampleClass.java", "public static void foo()", "foo", "foobar"
+        )
+        java.deprecate_method(
+            tempdir + "/SampleClass.java",
+            "public static void foobar()",
+            DEPRECATION_WARNING.format(new_method="foo"),
+        )
+        # adding a comment when a javadoc and annotation already exists
+        java.deprecate_method(
+            tempdir + "/SampleClass.java",
+            "public static void foobar()",
+            ADDITIONAL_COMMENT.format(new_method="foo"),
+        )
+
+        assert_matches_golden(
+            "tests/testdata/SampleDeprecateMethodGolden.java",
+            tempdir + "/SampleClass.java",
+        )
+
+
 def test_fix_proto_license():
     with tempfile.TemporaryDirectory() as tempdir:
         temppath = Path(tempdir).resolve()

tests/testdata/SampleCopyMethodGolden.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dlp;
+
+class ExampleClass {
+  public static void foo() {
+    System.out.println("bar");
+  }
+
+  public static void foobar() {
+    System.out.println("bar");
+  }
+
+  public static class InnerClass {
+    public void asdf() {
+      System.out.println("qwer");
+    }
+
+    public void xyz() {
+      System.out.println("qwer");
+    }
+  }
+}

tests/testdata/SampleDeprecateMethodGolden.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dlp;
+
+class ExampleClass {
+  public static void foo() {
+    System.out.println("bar");
+  }
+
+  /*
+   * @deprecated This method will be removed in the next major version.
+   * Use {@link #foo()} instead
+   * foo has the same functionality as foobar.
+   */
+  @Deprecated
+  public static void foobar() {
+    System.out.println("bar");
+  }
+
+  public static class InnerClass {
+    public void asdf() {
+      System.out.println("qwer");
+    }
+  }
+}