Added Change utility class for representing change events + Moved Match class to org.onlab.util
Change-Id: I08e8cd8dd92983bd2764e83016b1abc0bf29388f
diff --git a/core/api/src/main/java/org/onosproject/event/Change.java b/core/api/src/main/java/org/onosproject/event/Change.java
new file mode 100644
index 0000000..b1d2b6f
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/event/Change.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.event;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Objects;
+
+/**
+ * Generic representation of an update.
+ *
+ * @param <T> type of value that was updated
+ */
+public class Change<T> {
+
+ private final T oldValue;
+ private final T newValue;
+
+ public Change(T oldValue, T newValue) {
+ this.oldValue = oldValue;
+ this.newValue = newValue;
+ }
+
+ /**
+ * Returns previous value.
+ * @return previous value.
+ */
+ public T oldValue() {
+ return oldValue;
+ }
+
+ /**
+ * Returns new or current value.
+ * @return new value.
+ */
+ public T newValue() {
+ return newValue;
+ }
+
+ @Override
+ public boolean equals(Object other) {
+ if (other == null || !(other instanceof Change)) {
+ return false;
+ }
+ Change<T> that = (Change<T>) other;
+ return Objects.equal(this.oldValue, that.oldValue) &&
+ Objects.equal(this.newValue, that.newValue);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hashCode(oldValue, newValue);
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(getClass())
+ .add("oldValue", oldValue)
+ .add("newValue", newValue)
+ .toString();
+ }
+}