Clean code a bit

Author: andrei-punko

sound-recorder-n-spectrum-analyzer/src/main/java/by/andd3dfx/capturesound/AudioCaptureApp.java

@@ -88,7 +88,7 @@ public AudioCaptureApp() {
 
 
             double frequency = frequencyScanner.detectFrequency(audioData, (int) audioFormat.getSampleRate())
-                    .getMaxFrequency();
+                    .maxFrequency();
             System.out.println("Freq=" + frequency);
 
             AudioInputStream audioInputStream = new AudioInputStream(

sound-recorder-n-spectrum-analyzer/src/main/java/by/andd3dfx/capturesound/ShowRealTimeSpectrumApp.java

@@ -42,8 +42,8 @@ public static void main(String[] args) throws LineUnavailableException {
             byteArrayOutputStream.reset();
 
             FrequencyInfoContainer frequencyInfoContainer = frequencyScanner.detectFrequency(audioData, (int) audioFormat.getSampleRate());
-            double[] frequencies = frequencyInfoContainer.getFrequencies();
-            double[] magnitudes = frequencyInfoContainer.getMagnitudes();
+            double[] frequencies = frequencyInfoContainer.frequencies();
+            double[] magnitudes = frequencyInfoContainer.magnitudes();
 
             int N = 1_000;
             double[] xData = new double[N];
@@ -55,9 +55,9 @@ public static void main(String[] args) throws LineUnavailableException {
                     yData[bucketIndex] += magnitudes[bucketIndex * magnitudes.length / N + i];
                 }
             }
-            int maxFrequency = (int) frequencyInfoContainer.getMaxFrequency();
+            var maxFrequency = frequencyInfoContainer.maxFrequency();
 
-            String title = String.format("%d Hz", maxFrequency);
+            String title = String.format("%1$.0f Hz", maxFrequency);
             chartContainer.update(xData, yData, title);
         }
     }

sound-recorder-n-spectrum-analyzer/src/main/java/by/andd3dfx/capturesound/dto/FrequencyInfoContainer.java

@@ -1,26 +1,7 @@
 package by.andd3dfx.capturesound.dto;
 
-public class FrequencyInfoContainer {
-
-    private final double[] frequencies;
-    private final double[] magnitudes;
-    private final double maxFrequency;
-
-    public FrequencyInfoContainer(double[] frequencies, double[] magnitudes, double maxFrequency) {
-        this.frequencies = frequencies;
-        this.magnitudes = magnitudes;
-        this.maxFrequency = maxFrequency;
-    }
-
-    public double[] getFrequencies() {
-        return frequencies;
-    }
-
-    public double[] getMagnitudes() {
-        return magnitudes;
-    }
-
-    public double getMaxFrequency() {
-        return maxFrequency;
-    }
+public record FrequencyInfoContainer(
+        double[] frequencies,
+        double[] magnitudes,
+        double maxFrequency) {
 }

sound-recorder-n-spectrum-analyzer/src/main/java/by/andd3dfx/capturesound/fft/FrequencyScanner.java

@@ -30,32 +30,34 @@ public FrequencyInfoContainer detectFrequency(byte[] audioData, int sampleRate)
      */
     public FrequencyInfoContainer extractFrequencyInfo(short[] sampleData, int sampleRate) {
         /* sampleData + zero padding */
-        DoubleFFT_1D fft = new DoubleFFT_1D(sampleData.length + 24 * sampleData.length);
-        double[] a = new double[(sampleData.length + 24 * sampleData.length) * 2];
+        final int sampleRateLen = sampleData.length;
+        final int aLen_2 = sampleRateLen + 24 * sampleRateLen;
+        double[] a = new double[aLen_2 * 2];
+        var fft = new DoubleFFT_1D(aLen_2);
 
-        System.arraycopy(applyWindow(sampleData), 0, a, 0, sampleData.length);
+        System.arraycopy(applyWindow(sampleData), 0, a, 0, sampleRateLen);
         fft.realForward(a);
 
-        double frequencies[] = new double[a.length / 2];
-        double magnitudes[] = new double[a.length / 2];
+        double[] frequencies = new double[aLen_2];
+        double[] magnitudes = new double[aLen_2];
 
         /* find the peak magnitude and it's index */
         double maxMag = Double.NEGATIVE_INFINITY;
         int maxInd = -1;
 
-        for (int i = 0; i < a.length / 2; ++i) {
+        for (int i = 0; i < aLen_2; ++i) {
             double re = a[2 * i];
             double im = a[2 * i + 1];
             double mag = Math.sqrt(re * re + im * im);
-            frequencies[i] = (double) sampleRate * i / (a.length / 2);
+            frequencies[i] = (double) sampleRate * i / aLen_2;
             magnitudes[i] = mag;
 
             if (mag > maxMag) {
                 maxMag = mag;
                 maxInd = i;
             }
         }
-        double maxFrequency = (double) sampleRate * maxInd / (a.length / 2);
+        double maxFrequency = (double) sampleRate * maxInd / aLen_2;
         return new FrequencyInfoContainer(frequencies, magnitudes, maxFrequency);
     }
 
@@ -83,10 +85,11 @@ private void buildHammingWindow(int size) {
      * @return a double array containing the filtered data
      */
     private double[] applyWindow(short[] input) {
-        double[] res = new double[input.length];
+        var len = input.length;
+        double[] res = new double[len];
 
-        buildHammingWindow(input.length);
-        for (int i = 0; i < input.length; ++i) {
+        buildHammingWindow(len);
+        for (int i = 0; i < len; ++i) {
             res[i] = (double) input[i] * windowFilter[i];
         }
         return res;