Feature/refactor code smells

pom.xml

@@ -45,7 +45,7 @@
     <dependency>
       <groupId>org.testng</groupId>
       <artifactId>testng</artifactId>
-      <version>6.8.8</version>
+      <version>7.5.1</version>
       <scope>test</scope>
     </dependency>
     <dependency>

src/main/java/net/jodah/expiringmap/ExpiringEntry.java

@@ -0,0 +1,113 @@
+package net.jodah.expiringmap;
+
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/** Expiring map entry implementation. */
+class ExpiringEntry<K, V> implements Comparable<ExpiringEntry<K, V>> {
+  final AtomicLong expirationNanos;
+  /** Epoch time at which the entry is expected to expire */
+  final AtomicLong expectedExpiration;
+  final AtomicReference<ExpirationPolicy> expirationPolicy;
+  final K key;
+  /** Guarded by "this" */
+  volatile Future<?> entryFuture;
+  /** Guarded by "this" */
+  V value;
+  /** Guarded by "this" */
+  volatile boolean scheduled;
+
+  /**
+   * Creates a new ExpiringEntry object.
+   * 
+   * @param key for the entry
+   * @param value for the entry
+   * @param expirationPolicy for the entry
+   * @param expirationNanos for the entry
+   */
+  ExpiringEntry(K key, V value, AtomicReference<ExpirationPolicy> expirationPolicy, AtomicLong expirationNanos) {
+    this.key = key;
+    this.value = value;
+    this.expirationPolicy = expirationPolicy;
+    this.expirationNanos = expirationNanos;
+    this.expectedExpiration = new AtomicLong();
+    resetExpiration();
+  }
+
+  @Override
+  public int compareTo(ExpiringEntry<K, V> other) {
+    if (key.equals(other.key))
+      return 0;
+    return expectedExpiration.get() < other.expectedExpiration.get() ? -1 : 1;
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((key == null) ? 0 : key.hashCode());
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ExpiringEntry<?, ?> other = (ExpiringEntry<?, ?>) obj;
+    if (!key.equals(other.key))
+      return false;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!value.equals(other.value))
+      return false;
+    return true;
+  }
+
+  @Override
+  public String toString() {
+    return value.toString();
+  }
+
+  /**
+   * Marks the entry as canceled.
+   * 
+   * @return true if the entry was scheduled
+   */
+  synchronized boolean cancel() {
+    boolean result = scheduled;
+    if (entryFuture != null)
+      entryFuture.cancel(false);
+
+    entryFuture = null;
+    scheduled = false;
+    return result;
+  }
+
+  /** Gets the entry value. */
+  synchronized V getValue() {
+    return value;
+  }
+
+  /** Resets the entry's expected expiration. */
+  void resetExpiration() {
+    expectedExpiration.set(expirationNanos.get() + System.nanoTime());
+  }
+
+  /** Marks the entry as scheduled. */
+  synchronized void schedule(Future<?> entryFuture) {
+    this.entryFuture = entryFuture;
+    scheduled = true;
+  }
+
+  /** Sets the entry value. */
+  synchronized void setValue(V value) {
+    this.value = value;
+  }
+}