28-multi-thread-program-logic

src/main/java/com/CDPrintable/Constants.java

@@ -15,4 +15,7 @@ public class Constants {
     public static final String VERSION = "1.6.4";
 
     public static final boolean USER_AGENT_EMAIL_CHANGED = false;
-}
+
+    public static final int MAX_THREADS = 4;
+    public static final ThreadManager THREAD_MANAGER = new ThreadManager();
+}

src/main/java/com/CDPrintable/MusicBrainzResources/MusicBrainzJSONReader.java

@@ -10,12 +10,17 @@
 
 package com.CDPrintable.MusicBrainzResources;
 
+import com.CDPrintable.Constants;
 import com.google.gson.*;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 
+import javax.swing.*;
 import javax.swing.table.DefaultTableModel;
 import java.lang.reflect.Array;
+import java.util.concurrent.Future;
 
 public class MusicBrainzJSONReader {
     private final JsonObject json;
@@ -36,6 +41,28 @@ public MusicBrainzJSONReader(String json) throws IllegalArgumentException {
         this.json = tempJsonObject;
     }
 
+    /**
+     * This method splits a JSON array into smaller chunks for multithreading.
+     * @param jsonArray The JSON array to split.
+     */
+    public JsonArray[] splitJsonArray(JsonArray jsonArray) {
+        int chunkSize = Constants.MAX_THREADS;
+        int arraySize = jsonArray.size();
+        int numChunks = (int) Math.ceil((double) arraySize / chunkSize);
+        JsonArray[] chunks = new JsonArray[numChunks];
+
+        for (int i = 0; i < numChunks; i++) {
+            int start = i * chunkSize;
+            int end = Math.min(start + chunkSize, arraySize);
+            JsonArray chunk = new JsonArray();
+            for (int j = start; j < end; j++) {
+                chunk.add(jsonArray.get(j));
+            }
+            chunks[i] = chunk;
+        }
+        return chunks;
+    }
+
     /**
      * Parses a JSON array and creates a new array of the same type as the provided array.
      *
@@ -49,22 +76,40 @@ public MusicBrainzJSONReader(String json) throws IllegalArgumentException {
      */
     @SuppressWarnings("unchecked")
     private <T> T[] parseJsonArray(String key, JsonArrayProcessor<T> processor, T[] array) {
-        // Make sure the key exists in the JSON object
-        if (!json.has(key)) {
-            // Return an empty array if the JSON object does not have the key
-            array = (T[]) Array.newInstance(array.getClass().getComponentType(), 0);
-            return array;
+        if(!json.has(key)) {
+            // Return an empty array if the key does not exist
+            return (T[]) Array.newInstance(array.getClass().getComponentType(), 0);
         }
-        // Make a JSON array using the provided key
+
         JsonArray jsonArray = json.getAsJsonArray(key);
-        array = (T[]) Array.newInstance(array.getClass().getComponentType(), jsonArray.size());
+        JsonArray[] chunks = splitJsonArray(jsonArray);
 
-        // Process each JSON object in the array
-        for (int i = 0; i < jsonArray.size(); i++) {
-            JsonObject jsonObject = jsonArray.get(i).getAsJsonObject();
-            array[i] = processor.process(jsonObject);        // Uses provided processor to process the JSON object
+        // Use multithreading to process the JSON array
+        // This is a list of promises that promise to return a list
+        // of whatever type T is, e.g., MusicBrainzRelease.
+        List<Future<List<T>>> futures = new ArrayList<>();
+        for (JsonArray chunk : chunks) {
+            // Submit a task to the thread manager
+            futures.add(Constants.THREAD_MANAGER.submit(() -> {
+                List<T> result = new ArrayList<>();
+                for (JsonElement element : chunk) {
+                    JsonObject jsonObject = element.getAsJsonObject();
+                    result.add(processor.process(jsonObject));
+                }
+                return result;
+            }));
         }
-        return array;
+
+        List<T> resultList = new ArrayList<>();
+        try {
+            for (Future<List<T>> future : futures) {
+                resultList.addAll(future.get());
+            }
+        } catch (Exception e) {
+            JOptionPane.showMessageDialog(null, e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
+        }
+
+        return resultList.toArray((T[]) Array.newInstance(array.getClass().getComponentType(), resultList.size()));
     }
 
     /**

src/main/java/com/CDPrintable/ProgramWindow.java

@@ -23,6 +23,8 @@
 public class ProgramWindow {
     private final UserAgent userAgent;
     private JLabel fullUserAgentLabel = new JLabel();
+    private final JPanel cdSearchPanel = new JPanel();
+    private final JLabel searchStatusLabel = new JLabel("Status: Nothing's going on.");
 
     /**
      * Creates a new ProgramWindow and sets up the GUI.
@@ -76,20 +78,20 @@ private JPanel searchPanel() {
         JPanel panel = new JPanel();
         panel.setLayout(new BorderLayout());
 
-        // Track List panel set up
+        // Track List panel set-up
         JPanel trackListPanel = new JPanel(new BorderLayout());
         trackListPanel.setBorder(BorderFactory.createTitledBorder("Search Results"));
 
         // Search table set up
         JTable searchTable = new JTable(getCDStubModel());
         JScrollPane trackListScrollPane = new JScrollPane(searchTable);
+        trackListPanel.add(searchStatusLabel, BorderLayout.NORTH);
         trackListPanel.add(trackListScrollPane, BorderLayout.CENTER);
 
         // Add the Track List panel to the main panel
         panel.add(trackListPanel, BorderLayout.CENTER);
 
         // CD Search Panel set up
-        JPanel cdSearchPanel = new JPanel();
         cdSearchPanel.setBorder(BorderFactory.createTitledBorder("Search"));
 
         JTextField searchField = new JTextField(15);
@@ -102,26 +104,36 @@ private JPanel searchPanel() {
             if (searchTypeComboBox.getSelectedItem() == null) {
                 return;
             }
+            setSearchStatus("Preforming search...", "blue");
             if (searchTypeComboBox.getSelectedItem().equals("CDStub")) {
-                MusicBrainzJSONReader reader = sendRequest("cdstub", searchField.getText());
-
-                // Get CDStubs and set the table model
-                MusicBrainzCDStub[] cdStubs = reader.getCDStubs();
-                searchTable.setModel(reader.getCDStubsAsTableModel(cdStubs));
+                Constants.THREAD_MANAGER.submit(() -> {
+                    MusicBrainzJSONReader reader = sendRequest("cdstub", searchField.getText());
+
+                    // Get CDStubs and set the table model
+                    MusicBrainzCDStub[] cdStubs = reader.getCDStubs();
+                    searchTable.setModel(reader.getCDStubsAsTableModel(cdStubs));
+                    setSearchStatus("All done!", "green");
+                });
             } else if (searchTypeComboBox.getSelectedItem().equals("Artist")) {
-                MusicBrainzJSONReader reader = sendRequest("artist", searchField.getText());
-
-                // Get Artists and set the table model
-                MusicBrainzArtist[] artists = reader.getArtists();
-                searchTable.setModel(reader.getArtistsAsTableModel(artists));
+                Constants.THREAD_MANAGER.submit(() -> {
+                    MusicBrainzJSONReader reader = sendRequest("artist", searchField.getText());
+
+                    // Get Artists and set the table model
+                    MusicBrainzArtist[] artists = reader.getArtists();
+                    searchTable.setModel(reader.getArtistsAsTableModel(artists));
+                    setSearchStatus("All done!", "green");
+                });
             } else if (searchTypeComboBox.getSelectedItem().equals("Release")) {
-                MusicBrainzJSONReader reader = sendRequest("release", searchField.getText());
-
-                // Get Releases and set the table model
-                MusicBrainzRelease[] releases = reader.getReleases();
-                searchTable.setModel(reader.getReleasesAsTableModel(releases));
+                Constants.THREAD_MANAGER.submit(() -> {
+                    MusicBrainzJSONReader reader = sendRequest("release", searchField.getText());
+
+                    // Get Releases and set the table model
+                    MusicBrainzRelease[] releases = reader.getReleases();
+                    searchTable.setModel(reader.getReleasesAsTableModel(releases));
+                    setSearchStatus("All done!", "green");
+                });
             } else {
-                // how does this even happen
+                // how does this even happen?
                 JOptionPane.showMessageDialog(panel, "Please select a search type.");
             }
             resizeColumnWidths(searchTable);
@@ -286,15 +298,15 @@ public void changedUpdate(DocumentEvent e) {}   // Not used
         userAgentPanel.add(fullAgentPanel, BorderLayout.NORTH);
         userAgentPanel.add(userAgentInputPanel, BorderLayout.CENTER);
 
-        // Add sub panels to main panel
+        // Add subpanels to the main panel
         panel.add(userAgentPanel);
         panel.add(fontPanel);
 
         return panel;
     }
 
     /**
-     * Helper method to resize a tables columns to fit the largest element.
+     * Helper method to resize a table column to fit the largest element.
      * @param table The table to resize.
      */
     private void resizeColumnWidths(JTable table) {
@@ -313,4 +325,8 @@ private void resizeColumnWidths(JTable table) {
             tableColumn.setPreferredWidth(preferredWidth + 2); // Add padding
         }
     }
+
+    public void setSearchStatus(String status, String color) {
+        searchStatusLabel.setText("<html><font color='" + color + "'>Status: " + status + "</font></html>");
+    }
 }

src/main/java/com/CDPrintable/ThreadManager.java

@@ -0,0 +1,32 @@
+/*
+ * CDPrintable: A program that prints labels with track listings for your CD cases.
+ * Copyright (C) 2025 Alexander McLean
+ *
+ * This source code is licensed under the GNU General Public License v3.0
+ * found in the LICENSE file in the root directory of this source tree.
+ *
+ * This class manages threads.
+ */
+
+package com.CDPrintable;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+public class ThreadManager {
+    private final ExecutorService executorService;
+
+    public ThreadManager() {
+        executorService = Executors.newFixedThreadPool(Constants.MAX_THREADS);
+    }
+
+    public <T> Future<T> submit(Callable<T> task) {
+        return executorService.submit(task);
+    }
+
+    public void submit(Runnable task) {
+        executorService.submit(task);
+    }
+}