refactor: adhere to Error Prone rules

src/main/java/com/fxminer/Quote.java

@@ -1,7 +1,7 @@
 package com.fxminer;
 
 import java.io.Serializable;
-import java.util.Date;
+import java.time.ZonedDateTime;
 
 /**
  * Container for basic asset data (FX currency pair, Stock and etc.).
@@ -20,7 +20,7 @@ public class Quote implements QuoteValidator, Serializable {
   protected double close;
   protected double adjClose;
   protected long volume;
-  protected Date timestamp;
+  protected ZonedDateTime timestamp;
 
   /** Trend. */
   protected String classifiedTrend;
@@ -32,14 +32,14 @@ public Quote(
       double close,
       double adjClose,
       long volume,
-      Date timestamp) {
+      ZonedDateTime timestamp) {
     this.open = open;
     this.high = high;
     this.low = low;
     this.close = close;
     this.adjClose = adjClose;
     this.volume = volume;
-    this.timestamp = new Date(timestamp.getTime());
+    this.timestamp = timestamp;
   }
 
   public double getAdjClose() {
@@ -66,12 +66,12 @@ public void setClassifiedTrend(String classifiedTrend) {
     this.classifiedTrend = classifiedTrend;
   }
 
-  public Date getTimestamp() {
-    return new Date(timestamp.getTime());
+  public ZonedDateTime getTimestamp() {
+    return timestamp;
   }
 
-  public void setTimestamp(Date timestamp) {
-    this.timestamp = new Date(timestamp.getTime());
+  public void setTimestamp(ZonedDateTime timestamp) {
+    this.timestamp = timestamp;
   }
 
   public double getOpen() {
@@ -107,11 +107,13 @@ public void setClose(double close) {
   }
 
   /** Checks if the data is clean and ready for calculations. */
+  @Override
   public boolean isCleanAttribute() {
     return open != 0 && high != 0 && low != 0 && close != 0;
   }
 
   /** Checks if the data is clean and ready for calculations. */
+  @Override
   public boolean isCleanClass() {
     return !classifiedTrend.equals(Trend.UNCERTAINTY.name())
         && !classifiedTrend.equals(Trend.RANGING.name());
@@ -121,7 +123,7 @@ public boolean isCleanClass() {
   public String toString() {
     var sb = new StringBuilder();
 
-    sb.append(timestamp.getTime()).append(",");
+    sb.append(timestamp.toEpochSecond()).append(",");
 
     // OHLC
     sb.append(open)

src/main/java/com/fxminer/Symbol.java

@@ -81,7 +81,7 @@ public long calculateAvgVol() {
 
     // calc mean
     for (var i = 0; i < 63; i++) {
-      stats.addValue(history.get(i).getVolume());
+      stats.addValue((double) history.get(i).getVolume());
     }
 
     return (long) stats.getMean();

src/main/java/com/fxminer/ZigZag.java

@@ -53,13 +53,7 @@ public ZigZag(int depth, int deviation, int backstep, double point) {
     deviationInPoints = deviation * point;
   }
 
-  /**
-   * Searches for index of the highest bar.
-   *
-   * @param array
-   * @param depth
-   * @param startPos
-   */
+  /** Searches for index of the highest bar. */
   private int iHighest(double[] array, int depth, int startPos) {
     var index = startPos;
 
@@ -85,16 +79,10 @@ private int iHighest(double[] array, int depth, int startPos) {
     }
 
     // --- return index of the highest bar
-    return (index);
+    return index;
   }
 
-  /**
-   * Searches for index of the lowest bar
-   *
-   * @param array
-   * @param depth
-   * @param startPos
-   */
+  /** Searches for index of the lowest bar */
   private int iLowest(double[] array, int depth, int startPos) {
     var index = startPos;
 
@@ -120,16 +108,10 @@ private int iLowest(double[] array, int depth, int startPos) {
     }
 
     // --- return index of the lowest bar
-    return (index);
+    return index;
   }
 
-  /**
-   * Performs custom calculation.
-   *
-   * @param ratesTotal
-   * @param high
-   * @param low
-   */
+  /** Performs custom calculation. */
   public void calculate(int ratesTotal, double[] high, double[] low) {
     init(ratesTotal);
 
@@ -210,12 +192,7 @@ private void searchForPeak() {
     }
   }
 
-  /**
-   * Searches for peak or lawn.
-   *
-   * @param high
-   * @param low
-   */
+  /** Searches for peak or lawn. */
   private void searchForPeakOrLawn(double[] high, double[] low) {
     if (lastlow == 0 && lasthigh == 0) {
       if (highMapBuffer[shift] != 0) {
@@ -234,13 +211,7 @@ private void searchForPeakOrLawn(double[] high, double[] low) {
     }
   }
 
-  /**
-   * Searches for high and low.
-   *
-   * @param ratesTotal
-   * @param high
-   * @param low
-   */
+  /** Searches for high and low. */
   private void searchForHighAndLow(int ratesTotal, double[] high, double[] low) {
     for (shift = limit; shift < ratesTotal; shift++) {
       handleLowFound(low);
@@ -250,11 +221,7 @@ private void searchForHighAndLow(int ratesTotal, double[] high, double[] low) {
     }
   }
 
-  /**
-   * Handles low found.
-   *
-   * @param low
-   */
+  /** Handles low found. */
   private void handleLowFound(double[] low) {
     val = low[iLowest(low, depth, shift)];
 
@@ -276,11 +243,7 @@ private void handleLowFound(double[] low) {
     else lowMapBuffer[shift] = 0.0;
   }
 
-  /**
-   * Handles found high.
-   *
-   * @param high
-   */
+  /** Handles found high. */
   private void handleHighFound(double[] high) {
     val = high[iHighest(high, depth, shift)];
 
@@ -302,11 +265,7 @@ private void handleHighFound(double[] high) {
     else highMapBuffer[shift] = 0.0;
   }
 
-  /**
-   * Performs calculations if previously done.
-   *
-   * @param ratesTotal
-   */
+  /** Performs calculations if previously done. */
   private void calculateIfAlreadyCountedBefore(int ratesTotal) {
     int i;
     if (prevCalculated > 0) {
@@ -342,11 +301,7 @@ private void calculateIfAlreadyCountedBefore(int ratesTotal) {
     }
   }
 
-  /**
-   * Initializes variables.
-   *
-   * @param ratesTotal
-   */
+  /** Initializes variables. */
   private void init(int ratesTotal) {
     limit = 0;
     counterZ = 0;