Added format and optimize imports entry point.

core/src/main/java/com/google/googlejavaformat/java/Formatter.java

@@ -32,6 +32,7 @@
 import com.google.googlejavaformat.Newlines;
 import com.google.googlejavaformat.Op;
 import com.google.googlejavaformat.OpsBuilder;
+import com.google.googlejavaformat.java.RemoveUnusedImports.JavadocOnlyImports;
 import com.sun.tools.javac.file.JavacFileManager;
 import com.sun.tools.javac.parser.JavacParser;
 import com.sun.tools.javac.parser.ParserFactory;
@@ -194,6 +195,8 @@ public void formatSource(CharSource input, CharSink output)
   /**
    * Format an input string (a Java compilation unit) into an output string.
    *
+   * <p>Leaves import statements untouched.
+   *
    * @param input the input string
    * @return the output string
    * @throws FormatterException if the input string cannot be parsed
@@ -202,6 +205,25 @@ public String formatSource(String input) throws FormatterException {
     return formatSource(input, Collections.singleton(Range.closedOpen(0, input.length())));
   }
 
+  /**
+   * Format an input string (a Java compilation unit) and optimize imports into an output string.
+   *
+   * <p>Optimizing imports includes ordering, spacing and removal of unused import statements. An
+   * import used only in a Javadoc comment is considered as unused and therefore removed from the
+   * import statements and its usage within the comment replaced by its fully qualified name.
+   *
+   * @param input the input string
+   * @return the output string
+   * @throws FormatterException if the input string cannot be parsed
+   * @see <a href="https://google.github.io/styleguide/javaguide.html#s3.3.3-import-ordering-and-spacing">
+   *   Google Java Style Guide - 3.3.3 Import ordering and spacing</a>
+   */
+  public String formatSourceAndOptimizeImports(String input) throws FormatterException {
+    input = ImportOrderer.reorderImports(input);
+    input = RemoveUnusedImports.removeUnusedImports(input, JavadocOnlyImports.REMOVE);
+    return formatSource(input);
+  }
+
   /**
    * Format an input string (a Java compilation unit), for only the specified character ranges.
    * These ranges are extended as necessary (e.g., to encompass whole lines).

core/src/test/java/com/google/googlejavaformat/java/FormatterTest.java

@@ -248,6 +248,15 @@ public void importsNotReorderedByDefault() throws FormatterException {
     assertThat(output).isEqualTo(expect);
   }
 
+  @Test
+  public void importsOptimizedIfRequested() throws FormatterException {
+    String input =
+      "package com.google.example;\n" + UNORDERED_IMPORTS + "\npublic class ExampleTest {}\n";
+    String output = new Formatter().formatSourceAndOptimizeImports(input);
+    String expect = "package com.google.example;\n\npublic class ExampleTest {}\n";
+    assertThat(output).isEqualTo(expect);
+  }
+
   @Test
   public void importOrderingWithoutFormatting() throws IOException, UsageException {
     importOrdering(

core/src/test/java/com/google/googlejavaformat/java/MainTest.java

@@ -30,6 +30,7 @@
 import java.nio.file.Paths;
 import java.nio.file.attribute.PosixFilePermission;
 import java.util.EnumSet;
+import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -204,6 +205,40 @@ public void imports() throws Exception {
     }
   }
 
+  @Test
+  @Ignore("FormatFileCallable.call() needs a second format run after fixing imports")
+  public void optimizeImportsDoesNotLeaveEmptyLines() throws Exception {
+    String[] input = {
+      "package abc;",
+      "",
+      "import java.util.LinkedList;",
+      "import java.util.List;",
+      "import java.util.ArrayList;",
+      "",
+      "import static java.nio.charset.StandardCharsets.UTF_8;",
+      "",
+      "import java.util.EnumSet;",
+      "",
+      "class Test ",
+      "extends ArrayList {",
+      "}"
+    };
+    {
+      String[] expected = {
+        "package abc;", "", "import java.util.ArrayList;", "", "class Test extends ArrayList {}", ""
+      };
+      // pre-check expectation with local formatter instance
+      String optimized = new Formatter().formatSourceAndOptimizeImports(joiner.join(input));
+      assertThat(optimized).isEqualTo(joiner.join(expected));
+
+      InputStream in = new ByteArrayInputStream(joiner.join(input).getBytes(UTF_8));
+      StringWriter out = new StringWriter();
+      Main main = new Main(new PrintWriter(out, true), new PrintWriter(System.err, true), in);
+      assertThat(main.format("-")).isEqualTo(0);
+      assertThat(out.toString()).isEqualTo(joiner.join(expected));
+    }
+  }
+
   // test that -lines handling works with import removal
   @Test
   public void importRemovalLines() throws Exception {