Enforce Google Java Format for PiranhaJava (#34)

This patch:

1. Runs GJF on all existing Java files under `java/`
2. Updates the sample app original and expected output under 
    `sample/src/main/resources/com/uber/mylib/`
3. Sets up the build so that GJF is added as a git pre-commit hook
    whenever `./gradlew` is run under `java/`
4. Adds `verGJF` to the travis build for PiranhaJava, which will 
    fail the build on any non-GJF formatted java files.

.travis.yml

@@ -11,7 +11,7 @@ matrix:
       before_script:
         - cd java/
       script:
-        - ./gradlew build
+        - ./gradlew verGJF build
       after_success:
         - ./gradlew jacocoTestReport coveralls
       cache:

java/build.gradle

@@ -35,6 +35,7 @@ subprojects { project ->
         errorproneJavac deps.build.errorProneJavac
     }
     project.tasks.withType(JavaCompile) {
+        dependsOn(installGitHooks)
         options.compilerArgs += [
             "-Xlint:unchecked",
             "-Xlint:rawtypes"
@@ -57,3 +58,16 @@ subprojects { project ->
 googleJavaFormat {
   toolVersion = "1.6"
 }
+
+////////////////////////////////////////////////////////////////////////
+//
+//  Google Java Format pre-commit hook installation
+//
+
+tasks.register('installGitHooks', Copy) {
+	from(file('config/hooks/pre-commit-stub')) {
+		rename 'pre-commit-stub', 'pre-commit'
+	}
+	into file('../.git/hooks')
+	fileMode 0777
+}

java/config/hooks/pre-commit

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -e
+
+REPO_ROOT_DIR="$(git rev-parse --show-toplevel)"
+
+pushd "${REPO_ROOT_DIR}/java" > /dev/null
+files=$((git diff --cached --name-only --diff-filter=ACMR | grep -Ei "\.java$" | sed -e 's/^java\///') || true)
+if [ ! -z "${files}" ]; then
+    comma_files=$(echo "$files" | paste -s -d "," -)
+    "${REPO_ROOT_DIR}/java/gradlew" goJF -DgoogleJavaFormat.include="$comma_files" &>/dev/null
+    git add $(echo "$files" | paste -s -d " " -)
+fi
+popd > /dev/null

java/config/hooks/pre-commit-stub

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# stub pre-commit hook
+# just a runner for the real pre-commit script
+# if script cannot be found, exit without error
+# (to not block local commits)
+
+set -e
+
+REPO_ROOT_DIR="$(git rev-parse --show-toplevel)"
+PRE_COMMIT_SCRIPT="${REPO_ROOT_DIR}/java/config/hooks/pre-commit"
+
+if [ -f $PRE_COMMIT_SCRIPT ]; then
+    source $PRE_COMMIT_SCRIPT
+fi

java/piranha/src/main/java/com/uber/piranha/PiranhaUtils.java

@@ -1,17 +1,15 @@
 /**
- *    Copyright (c) 2019 Uber Technologies, Inc.
+ * Copyright (c) 2019 Uber Technologies, Inc.
  *
- *    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
+ * <p>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
  *
- *        http://www.apache.org/licenses/LICENSE-2.0
+ * <p>http://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.
+ * <p>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 com.uber.piranha;
 
@@ -20,5 +18,4 @@ public class PiranhaUtils {
       "//[PIRANHA_DELETE_FILE_SEQ] Delete this class.\n";
 
   public static final String HELPER_CLASS = "// [PIRANHA_STALE_PLUGIN_HELPER_CLASS]";
-
 }

java/piranha/src/main/java/com/uber/piranha/UsageCounter.java

@@ -1,17 +1,15 @@
 /**
- *    Copyright (c) 2019 Uber Technologies, Inc.
+ * Copyright (c) 2019 Uber Technologies, Inc.
  *
- *    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
+ * <p>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
  *
- *        http://www.apache.org/licenses/LICENSE-2.0
+ * <p>http://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.
+ * <p>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 com.uber.piranha;
 
@@ -34,147 +32,145 @@
 import java.util.Map;
 import java.util.Set;
 
-/**
- * Originally from com.uber.errorprone.checker.dagger.UsageCounter
- */
+/** Originally from com.uber.errorprone.checker.dagger.UsageCounter */
 public final class UsageCounter {
 
-    private UsageCounter() {
-        /* Helper class only, not instantiable */
+  private UsageCounter() {
+    /* Helper class only, not instantiable */
+  }
+
+  private static boolean symbolHasSuppressUnusedCheckerWarningsAnnotation(
+      Symbol symbol, String checkerName) {
+    SuppressWarnings annotation = symbol.getAnnotation(SuppressWarnings.class);
+    if (annotation != null) {
+      for (String s : annotation.value()) {
+        if (s.equals(checkerName)) return true;
+      }
     }
-
-    private static boolean symbolHasSuppressUnusedCheckerWarningsAnnotation(
-            Symbol symbol, String checkerName) {
-        SuppressWarnings annotation = symbol.getAnnotation(SuppressWarnings.class);
-        if (annotation != null) {
-            for (String s : annotation.value()) {
-                if (s.equals(checkerName)) return true;
-            }
-        }
-        return false;
+    return false;
+  }
+
+  public static ImmutableMap<Symbol, CounterData> getUsageCounts(VisitorState state) {
+    return getUsageCounts(state, state.getPath());
+  }
+
+  public static ImmutableMap<Symbol, CounterData> getUsageCounts(
+      VisitorState state, TreePath path) {
+    UsageCounter.CallScanner callScanner = new UsageCounter.CallScanner(state);
+    callScanner.scan(path, null);
+    ImmutableMap.Builder<Symbol, CounterData> builder = ImmutableMap.builder();
+    for (VariableTree decl : callScanner.declaredInjectVars) {
+      Symbol s = ASTHelpers.getSymbol(decl);
+      CounterData counterData =
+          new CounterData(
+              DeclType.FIELD,
+              decl,
+              (callScanner.usedVars.containsKey(s) ? callScanner.usedVars.get(s) : 0));
+      builder.put(s, counterData);
     }
 
-    public static ImmutableMap<Symbol, CounterData> getUsageCounts(VisitorState state) {
-        return getUsageCounts(state, state.getPath());
+    for (VariableTree decl : callScanner.declaredParamVars.keySet()) {
+      Symbol s = ASTHelpers.getSymbol(decl);
+      Symbol.MethodSymbol mSym = callScanner.declaredParamVars.get(decl);
+      CounterData counterData =
+          new CounterData(
+              DeclType.PARAM,
+              decl,
+              (callScanner.usedVars.containsKey(s) ? callScanner.usedVars.get(s) : 0));
+      builder.put(s, counterData);
+    }
+    return builder.build();
+  }
+
+  public static ImmutableMap<Symbol, Integer> getRawUsageCounts(Tree tree) {
+    RawUsageCountsScanner scanner = new RawUsageCountsScanner();
+    scanner.scan(tree, null);
+    return ImmutableMap.copyOf(scanner.usedVars);
+  }
+
+  private static void addUse(Map<Symbol, Integer> usedVars, Symbol symbol) {
+    if (usedVars.containsKey(symbol)) {
+      usedVars.put(symbol, usedVars.get(symbol) + 1);
+    } else {
+      usedVars.put(symbol, 1);
     }
+  }
 
-    public static ImmutableMap<Symbol, CounterData> getUsageCounts(
-            VisitorState state, TreePath path) {
-        UsageCounter.CallScanner callScanner = new UsageCounter.CallScanner(state);
-        callScanner.scan(path, null);
-        ImmutableMap.Builder<Symbol, CounterData> builder = ImmutableMap.builder();
-        for (VariableTree decl : callScanner.declaredInjectVars) {
-            Symbol s = ASTHelpers.getSymbol(decl);
-            CounterData counterData =
-                    new CounterData(
-                            DeclType.FIELD,
-                            decl,
-                            (callScanner.usedVars.containsKey(s) ? callScanner.usedVars.get(s) : 0));
-            builder.put(s, counterData);
-        }
+  static class CallScanner extends TreePathScanner<Void, Void> {
+    final Set<VariableTree> declaredInjectVars = new LinkedHashSet<>();
+    final HashMap<VariableTree, Symbol.MethodSymbol> declaredParamVars =
+        new HashMap<VariableTree, Symbol.MethodSymbol>();
+    final Map<Symbol, Integer> usedVars = new LinkedHashMap<>();
+    final VisitorState state;
 
-        for (VariableTree decl : callScanner.declaredParamVars.keySet()) {
-            Symbol s = ASTHelpers.getSymbol(decl);
-            Symbol.MethodSymbol mSym = callScanner.declaredParamVars.get(decl);
-            CounterData counterData =
-                    new CounterData(
-                            DeclType.PARAM,
-                            decl,
-                            (callScanner.usedVars.containsKey(s) ? callScanner.usedVars.get(s) : 0));
-            builder.put(s, counterData);
-        }
-        return builder.build();
+    CallScanner(VisitorState state) {
+      this.state = state;
     }
 
-    public static ImmutableMap<Symbol, Integer> getRawUsageCounts(Tree tree) {
-        RawUsageCountsScanner scanner = new RawUsageCountsScanner();
-        scanner.scan(tree, null);
-        return ImmutableMap.copyOf(scanner.usedVars);
+    @Override
+    public Void visitMemberSelect(MemberSelectTree tree, Void unused) {
+      addUse(usedVars, ASTHelpers.getSymbol(tree));
+      return super.visitMemberSelect(tree, null);
     }
 
-    private static void addUse(Map<Symbol, Integer> usedVars, Symbol symbol) {
-        if (usedVars.containsKey(symbol)) {
-            usedVars.put(symbol, usedVars.get(symbol) + 1);
-        } else {
-            usedVars.put(symbol, 1);
-        }
+    @Override
+    public Void visitIdentifier(IdentifierTree tree, Void unused) {
+      addUse(usedVars, ASTHelpers.getSymbol(tree));
+      return super.visitIdentifier(tree, null);
     }
 
-    static class CallScanner extends TreePathScanner<Void, Void> {
-        final Set<VariableTree> declaredInjectVars = new LinkedHashSet<>();
-        final HashMap<VariableTree, Symbol.MethodSymbol> declaredParamVars =
-                new HashMap<VariableTree, Symbol.MethodSymbol>();
-        final Map<Symbol, Integer> usedVars = new LinkedHashMap<>();
-        final VisitorState state;
-
-        CallScanner(VisitorState state) {
-            this.state = state;
-        }
-
-        @Override
-        public Void visitMemberSelect(MemberSelectTree tree, Void unused) {
-            addUse(usedVars, ASTHelpers.getSymbol(tree));
-            return super.visitMemberSelect(tree, null);
-        }
-
-        @Override
-        public Void visitIdentifier(IdentifierTree tree, Void unused) {
-            addUse(usedVars, ASTHelpers.getSymbol(tree));
-            return super.visitIdentifier(tree, null);
-        }
-
-        @Override
-        public Void visitMethod(MethodTree tree, Void unused) {
-            Symbol.MethodSymbol mSym = ASTHelpers.getSymbol(tree);
-            if (ASTHelpers.hasAnnotation(mSym, "dagger.Provides", state)) {
-                for (VariableTree vt : tree.getParameters()) {
-                    declaredParamVars.put(vt, mSym);
-                }
-            }
-            return super.visitMethod(tree, null);
+    @Override
+    public Void visitMethod(MethodTree tree, Void unused) {
+      Symbol.MethodSymbol mSym = ASTHelpers.getSymbol(tree);
+      if (ASTHelpers.hasAnnotation(mSym, "dagger.Provides", state)) {
+        for (VariableTree vt : tree.getParameters()) {
+          declaredParamVars.put(vt, mSym);
         }
+      }
+      return super.visitMethod(tree, null);
+    }
 
-        @Override
-        public Void visitVariable(VariableTree tree, Void unused) {
-            Symbol.VarSymbol vSym = ASTHelpers.getSymbol(tree);
-            if (ASTHelpers.hasAnnotation(vSym, "javax.inject.Inject", state)) {
-                declaredInjectVars.add(tree);
-            }
-            return super.visitVariable(tree, null);
-        }
+    @Override
+    public Void visitVariable(VariableTree tree, Void unused) {
+      Symbol.VarSymbol vSym = ASTHelpers.getSymbol(tree);
+      if (ASTHelpers.hasAnnotation(vSym, "javax.inject.Inject", state)) {
+        declaredInjectVars.add(tree);
+      }
+      return super.visitVariable(tree, null);
     }
+  }
 
-    static class RawUsageCountsScanner extends TreeScanner<Void, Void> {
-        final Map<Symbol, Integer> usedVars = new LinkedHashMap<>();
+  static class RawUsageCountsScanner extends TreeScanner<Void, Void> {
+    final Map<Symbol, Integer> usedVars = new LinkedHashMap<>();
 
-        @Override
-        public Void visitMemberSelect(MemberSelectTree tree, Void unused) {
-            addUse(usedVars, ASTHelpers.getSymbol(tree));
-            return super.visitMemberSelect(tree, null);
-        }
-
-        @Override
-        public Void visitIdentifier(IdentifierTree tree, Void unused) {
-            addUse(usedVars, ASTHelpers.getSymbol(tree));
-            return super.visitIdentifier(tree, null);
-        }
+    @Override
+    public Void visitMemberSelect(MemberSelectTree tree, Void unused) {
+      addUse(usedVars, ASTHelpers.getSymbol(tree));
+      return super.visitMemberSelect(tree, null);
     }
 
-    public enum DeclType {
-        FIELD,
-        PARAM,
+    @Override
+    public Void visitIdentifier(IdentifierTree tree, Void unused) {
+      addUse(usedVars, ASTHelpers.getSymbol(tree));
+      return super.visitIdentifier(tree, null);
     }
-
-    public static class CounterData {
-        public final DeclType declType;
-        public final VariableTree declaration;
-        public final int count;
-
-        public CounterData(DeclType declType, VariableTree declaration, int count) {
-            Preconditions.checkArgument(count >= 0, "Count must be positive.");
-            this.declType = declType;
-            this.declaration = declaration;
-            this.count = count;
-        }
+  }
+
+  public enum DeclType {
+    FIELD,
+    PARAM,
+  }
+
+  public static class CounterData {
+    public final DeclType declType;
+    public final VariableTree declaration;
+    public final int count;
+
+    public CounterData(DeclType declType, VariableTree declaration, int count) {
+      Preconditions.checkArgument(count >= 0, "Count must be positive.");
+      this.declType = declType;
+      this.declaration = declaration;
+      this.count = count;
     }
+  }
 }