Add getLastChange, getLastUpdate, and getPreviousState to Gener…

…icItem

Signed-off-by: Jimmy Tanagra <[email protected]>

bundles/org.openhab.core/src/main/java/org/openhab/core/items/GenericItem.java

@@ -12,6 +12,7 @@
  */
 package org.openhab.core.items;
 
+import java.time.ZonedDateTime;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -77,6 +78,10 @@ public abstract class GenericItem implements ActiveItem {
     protected final String type;
 
     protected State state = UnDefType.NULL;
+    protected @Nullable State previousState;
+
+    protected @Nullable ZonedDateTime lastUpdate;
+    protected @Nullable ZonedDateTime lastChange;
 
     protected @Nullable String label;
 
@@ -103,6 +108,33 @@ public State getState() {
         return state.as(typeClass);
     }
 
+    /**
+     * Returns the previous state of the item.
+     * 
+     * @return the previous state of the item, or null if the item has never been changed.
+     */
+    public @Nullable State getPreviousState() {
+        return previousState;
+    }
+
+    /**
+     * Returns the time the item was last updated.
+     * 
+     * @return the time the item was last updated, or null if the item has never been updated.
+     */
+    public @Nullable ZonedDateTime getLastUpdate() {
+        return lastUpdate;
+    }
+
+    /**
+     * Returns the time the item was last changed.
+     * 
+     * @return the time the item was last changed, or null if the item has never been changed.
+     */
+    public @Nullable ZonedDateTime getLastChange() {
+        return lastChange;
+    }
+
     @Override
     public String getUID() {
         return getName();
@@ -218,13 +250,20 @@ public void setState(State state) {
      * @param state new state of this item
      */
     protected final void applyState(State state) {
+        ZonedDateTime now = ZonedDateTime.now();
         State oldState = this.state;
+        boolean stateChanged = !oldState.equals(state);
         this.state = state;
+        if (stateChanged) {
+            previousState = oldState; // update before we notify listeners
+        }
         notifyListeners(oldState, state);
         sendStateUpdatedEvent(state);
-        if (!oldState.equals(state)) {
+        if (stateChanged) {
             sendStateChangedEvent(state, oldState);
+            lastChange = now; // update after we've notified listeners
         }
+        lastUpdate = now;
     }
 
     /**

bundles/org.openhab.core/src/test/java/org/openhab/core/items/GenericItemTest.java

@@ -13,11 +13,14 @@
 package org.openhab.core.items;
 
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.collection.IsCollectionWithSize.hasSize;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.Mockito.*;
 
+import java.time.ZonedDateTime;
 import java.util.List;
 import java.util.Locale;
 
@@ -39,6 +42,7 @@
 import org.openhab.core.types.State;
 import org.openhab.core.types.StateDescriptionFragmentBuilder;
 import org.openhab.core.types.StateOption;
+import org.openhab.core.types.UnDefType;
 
 /**
  * The GenericItemTest tests functionality of the GenericItem.
@@ -133,6 +137,47 @@ public void testGetStateAsWithNull() {
         assertNull(item.getStateAs(toNull()));
     }
 
+    @Test
+    public void testGetLastUpdate() {
+        TestItem item = new TestItem("member1");
+        assertNull(item.getLastUpdate());
+        item.setState(PercentType.HUNDRED);
+        assertThat(item.getLastUpdate().toInstant().toEpochMilli() * 1.0,
+                is(closeTo(ZonedDateTime.now().toInstant().toEpochMilli(), 5)));
+    }
+
+    @Test
+    public void testGetLastChange() throws InterruptedException {
+        TestItem item = new TestItem("member1");
+        assertNull(item.getLastChange());
+        item.setState(PercentType.HUNDRED);
+        ZonedDateTime initialChangeTime = ZonedDateTime.now();
+        assertThat(item.getLastChange().toInstant().toEpochMilli() * 1.0,
+                is(closeTo(initialChangeTime.toInstant().toEpochMilli(), 5)));
+
+        Thread.sleep(50);
+        item.setState(PercentType.HUNDRED);
+        assertThat(item.getLastChange().toInstant().toEpochMilli() * 1.0,
+                is(closeTo(initialChangeTime.toInstant().toEpochMilli(), 5)));
+
+        Thread.sleep(50);
+        ZonedDateTime secondChangeTime = ZonedDateTime.now();
+        item.setState(PercentType.ZERO);
+        assertThat(item.getLastChange().toInstant().toEpochMilli() * 1.0,
+                is(closeTo(secondChangeTime.toInstant().toEpochMilli(), 5)));
+    }
+
+    @Test
+    public void testGetPreviousState() {
+        TestItem item = new TestItem("member1");
+        assertEquals(item.getState(), UnDefType.NULL);
+        assertNull(item.getPreviousState());
+        item.setState(PercentType.HUNDRED);
+        assertEquals(item.getPreviousState(), UnDefType.NULL);
+        item.setState(PercentType.ZERO);
+        assertEquals(item.getPreviousState(), PercentType.HUNDRED);
+    }
+
     @Test
     public void testDispose() {
         TestItem item = new TestItem("test");