Added client

Signed-off-by: Jim Martens <github@2martens.de>

04/src/ClientThread.java

@@ -0,0 +1,71 @@
+import java.util.concurrent.ThreadLocalRandom;
+
+/**
+ * Represents a client.
+ */
+public class ClientThread extends Thread {
+    private int _id;
+    private int _lowerPageBound;
+    private int _upperPageBound;
+    private PersistenceManager _manager;
+    
+    /**
+     * Initializes the thread.
+     * @param id             the ID of this client
+     * @param lowerPageBound smalles page ID that can be accessed by this client
+     * @param upperPageBound highest page ID that can be accessed by this client
+     */
+    public ClientThread(int id, int lowerPageBound, int upperPageBound) {
+        _id = id;
+        _lowerPageBound = lowerPageBound;
+        _upperPageBound = upperPageBound;
+        _manager = PersistenceManager.getInstance();
+    }
+    
+    /**
+     * Runs the thread.
+     */
+    public void run() {
+        while(true) {
+            try {
+                int taid = beginTransaction();
+                int numberOfWrites = ThreadLocalRandom.current().nextInt(0, 10);
+                for (int i = 0; i < numberOfWrites; ++i) {
+                    write(taid);
+                }
+                commit(taid);
+            } catch (InterruptedException e) {
+                return;
+            }
+        }
+    }
+    
+    /**
+     * Begins a transaction and returns the transaction ID.
+     * @return new transaction ID
+     */
+    private int beginTransaction() throws InterruptedException {
+        int taid = _manager.beginTransaction();
+        Thread.sleep(2000);
+        return taid;
+    }
+    
+    /**
+     * Commits the given transaction.
+     * @param taid the transaction ID
+     */
+    private void commit(int taid) throws InterruptedException {
+        _manager.commit(taid);
+        Thread.sleep(2000);
+    }
+    
+    /**
+     * Performs a write.
+     * @param taid the transaction ID used for this write
+     */
+    private void write(int taid) throws InterruptedException {
+        int pageID = ThreadLocalRandom.current().nextInt(_lowerPageBound, _upperPageBound + 1);
+        _manager.write(taid, pageID, "transaction " + taid + " of client " + _id);
+        Thread.sleep(2000);
+    }
+}