Added errorprone checks (#121)

Added errorprone plugin.
Fixed all errors and warnings that it reported.

Author: mfateev

build.gradle

@@ -7,6 +7,7 @@ buildscript {
 plugins {
     id 'net.minecrell.licenser' version '0.3'
     id "com.github.sherter.google-java-format" version "0.6"
+    id "net.ltgt.errorprone" version "0.0.13"
 }
 
 repositories {
@@ -52,7 +53,8 @@ license {
 
 compileJava {
     options.encoding = 'UTF-8'
-    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation"
+    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation" << "-XepExcludedPaths:" +
+            ".*/generated-sources/.*"
 }
 
 license {
@@ -63,7 +65,8 @@ license {
 
 compileTestJava {
     options.encoding = 'UTF-8'
-    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation"
+    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation" << "-XepExcludedPaths:" +
+            ".*/generated-sources/.*"
 }
 
 if (JavaVersion.current().isJava8Compatible()) {

src/main/java/com/uber/cadence/converter/JsonDataConverter.java

@@ -237,6 +237,7 @@ private StackTraceElement[] parseStackTrace(JsonObject object) {
         return new StackTraceElement[0];
       }
       try {
+        @SuppressWarnings("StringSplitter")
         String[] lines = stackTrace.split("\n");
         StackTraceElement[] result = new StackTraceElement[lines.length];
         for (int i = 0; i < lines.length; i++) {

src/main/java/com/uber/cadence/internal/common/StartWorkflowExecutionParameters.java

@@ -21,6 +21,7 @@
 import com.uber.cadence.WorkflowIdReusePolicy;
 import com.uber.cadence.WorkflowType;
 import com.uber.cadence.client.WorkflowOptions;
+import java.nio.charset.StandardCharsets;
 
 public class StartWorkflowExecutionParameters {
 
@@ -291,14 +292,14 @@ public String toString() {
     sb.append("WorkflowId: " + workflowId + ", ");
     sb.append("WorkflowType: " + workflowType + ", ");
     sb.append("TaskList: " + taskList + ", ");
-    sb.append("Input: " + input + ", ");
+    sb.append("Input: " + new String(input, 0, 512, StandardCharsets.UTF_8) + ", ");
     sb.append("StartToCloseTimeout: " + executionStartToCloseTimeoutSeconds + ", ");
     sb.append("ChildPolicy: " + childPolicy + ", ");
     sb.append("}");
     return sb.toString();
   }
 
-  public StartWorkflowExecutionParameters clone() {
+  public StartWorkflowExecutionParameters copy() {
     StartWorkflowExecutionParameters result = new StartWorkflowExecutionParameters();
     result.setInput(input);
     result.setExecutionStartToCloseTimeoutSeconds(executionStartToCloseTimeoutSeconds);

src/main/java/com/uber/cadence/internal/common/WorkflowExecutionUtils.java

@@ -174,12 +174,13 @@ public static HistoryEvent getInstanceCloseEvent(
   }
 
   public static boolean isWorkflowExecutionCompletedEvent(HistoryEvent event) {
-    return ((event != null) && event.getEventType() == EventType.WorkflowExecutionCompleted
-        || event.getEventType() == EventType.WorkflowExecutionCanceled
-        || event.getEventType() == EventType.WorkflowExecutionFailed
-        || event.getEventType() == EventType.WorkflowExecutionTimedOut
-        || event.getEventType() == EventType.WorkflowExecutionContinuedAsNew
-        || event.getEventType() == EventType.WorkflowExecutionTerminated);
+    return ((event != null)
+        && (event.getEventType() == EventType.WorkflowExecutionCompleted
+            || event.getEventType() == EventType.WorkflowExecutionCanceled
+            || event.getEventType() == EventType.WorkflowExecutionFailed
+            || event.getEventType() == EventType.WorkflowExecutionTimedOut
+            || event.getEventType() == EventType.WorkflowExecutionContinuedAsNew
+            || event.getEventType() == EventType.WorkflowExecutionTerminated));
   }
 
   public static boolean isActivityTaskClosedEvent(HistoryEvent event) {
@@ -479,7 +480,7 @@ public static String prettyPrintHistory(History history, boolean showWorkflowTas
 
   public static String prettyPrintHistory(
       Iterator<HistoryEvent> events, boolean showWorkflowTasks) {
-    StringBuffer result = new StringBuffer();
+    StringBuilder result = new StringBuilder();
     result.append("{");
     boolean first = true;
     while (events.hasNext()) {
@@ -500,7 +501,7 @@ public static String prettyPrintHistory(
   }
 
   public static String prettyPrintDecisions(Iterable<Decision> decisions) {
-    StringBuffer result = new StringBuffer();
+    StringBuilder result = new StringBuilder();
     result.append("{");
     boolean first = true;
     for (Decision decision : decisions) {
@@ -523,7 +524,7 @@ public static String prettyPrintDecisions(Iterable<Decision> decisions) {
    */
   public static String prettyPrintHistoryEvent(HistoryEvent event) {
     String eventType = event.getEventType().toString();
-    StringBuffer result = new StringBuffer();
+    StringBuilder result = new StringBuilder();
     result.append(event.getEventId());
     result.append(": ");
     result.append(eventType);
@@ -562,7 +563,7 @@ private static String prettyPrintObject(
       String indentation,
       boolean skipLevel,
       boolean printTypeName) {
-    StringBuffer result = new StringBuffer();
+    StringBuilder result = new StringBuilder();
     if (object == null) {
       return "null";
     }

src/main/java/com/uber/cadence/internal/external/GenericWorkflowClientExternalImpl.java

@@ -47,6 +47,7 @@ public GenericWorkflowClientExternalImpl(WorkflowService.Iface service, String d
     this.domain = domain;
   }
 
+  @Override
   public String getDomain() {
     return domain;
   }

src/main/java/com/uber/cadence/internal/replay/ChildWorkflowDecisionStateMachine.java

@@ -77,6 +77,7 @@ public void handleStartedEvent(HistoryEvent event) {
       case CANCELED_AFTER_INITIATED:
         state = DecisionState.CANCELED_AFTER_STARTED;
         break;
+      default:
     }
     stateHistory.add(state.toString());
   }

src/main/java/com/uber/cadence/internal/replay/CompleteWorkflowStateMachine.java

@@ -30,6 +30,7 @@ public CompleteWorkflowStateMachine(DecisionId id, Decision decision) {
     this.decision = decision;
   }
 
+  @Override
   public DecisionId getId() {
     return id;
   }

src/main/java/com/uber/cadence/internal/replay/ContinueAsNewWorkflowExecutionParameters.java

@@ -18,6 +18,7 @@
 package com.uber.cadence.internal.replay;
 
 import com.uber.cadence.ChildPolicy;
+import java.nio.charset.StandardCharsets;
 
 public final class ContinueAsNewWorkflowExecutionParameters {
 
@@ -100,15 +101,15 @@ public ContinueAsNewWorkflowExecutionParameters withTaskStartToCloseTimeoutSecon
   public String toString() {
     StringBuilder sb = new StringBuilder();
     sb.append("{");
-    sb.append("Input: " + input + ", ");
+    sb.append("Input: " + new String(input, 0, 512, StandardCharsets.UTF_8) + ", ");
     sb.append("ExecutionStartToCloseTimeout: " + executionStartToCloseTimeoutSeconds + ", ");
     sb.append("TaskStartToCloseTimeout: " + taskStartToCloseTimeoutSeconds + ", ");
     sb.append("TaskList: " + taskList + ", ");
     sb.append("}");
     return sb.toString();
   }
 
-  public ContinueAsNewWorkflowExecutionParameters clone() {
+  public ContinueAsNewWorkflowExecutionParameters copy() {
     ContinueAsNewWorkflowExecutionParameters result =
         new ContinueAsNewWorkflowExecutionParameters();
     result.setExecutionStartToCloseTimeoutSeconds(executionStartToCloseTimeoutSeconds);

src/main/java/com/uber/cadence/internal/replay/DecisionContextImpl.java

@@ -128,6 +128,7 @@ public Consumer<Exception> startChildWorkflow(
     return workflowClient.startChildWorkflow(parameters, executionCallback, callback);
   }
 
+  @Override
   public Consumer<Exception> signalWorkflowExecution(
       SignalExternalWorkflowParameters signalParameters, BiConsumer<Void, Exception> callback) {
     return workflowClient.signalWorkflowExecution(signalParameters, callback);

src/main/java/com/uber/cadence/internal/replay/DecisionStateMachineBase.java

@@ -41,10 +41,12 @@ protected DecisionStateMachineBase(DecisionId id, DecisionState state) {
     stateHistory.add(state.toString());
   }
 
+  @Override
   public DecisionState getState() {
     return state;
   }
 
+  @Override
   public DecisionId getId() {
     return id;
   }
@@ -63,6 +65,7 @@ public void handleDecisionTaskStartedEvent() {
         state = DecisionState.DECISION_SENT;
         stateHistory.add(state.toString());
         break;
+      default:
     }
   }