--- /dev/null
+/*
+ * Copyright (c) 2015 Brocade Communications Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.mdsal.eos.common.api;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMap.Builder;
+import java.util.Map;
+
+/**
+ * Enumerates the ownership change states for an entity.
+ *
+ * @author Thomas Pantelis
+ */
+public enum EntityOwnershipChangeState {
+ /**
+ * The local process instance has been granted ownership.
+ */
+ LOCAL_OWNERSHIP_GRANTED(false, true, true),
+
+ /**
+ * The local process instance has lost ownership and another process instance is now the owner.
+ */
+ LOCAL_OWNERSHIP_LOST_NEW_OWNER(true, false, true),
+
+ /**
+ * The local process instance has lost ownership and there are no longer any candidates for the entity and
+ * thus has no owner.
+ */
+ LOCAL_OWNERSHIP_LOST_NO_OWNER(true, false, false),
+
+ /**
+ * Entity ownership has transitioned to another process instance and this instance was not the previous owner.
+ */
+ REMOTE_OWNERSHIP_CHANGED(false, false, true),
+
+ /**
+ * A remote process instance has lost ownership and there are no longer any candidates for the entity and
+ * thus has no owner.
+ */
+ REMOTE_OWNERSHIP_LOST_NO_OWNER(false, false, false);
+
+ private static final Map<Key, EntityOwnershipChangeState> BY_KEY;
+ static {
+ Builder<Key, EntityOwnershipChangeState> builder = ImmutableMap.<Key, EntityOwnershipChangeState>builder();
+ for(EntityOwnershipChangeState e: values()) {
+ builder.put(new Key(e.wasOwner, e.isOwner, e.hasOwner), e);
+ }
+
+ BY_KEY = builder.build();
+ }
+
+ private final boolean wasOwner;
+ private final boolean isOwner;
+ private final boolean hasOwner;
+
+ private EntityOwnershipChangeState(boolean wasOwner, boolean isOwner, boolean hasOwner) {
+ this.wasOwner = wasOwner;
+ this.isOwner = isOwner;
+ this.hasOwner = hasOwner;
+ }
+
+ /**
+ * Returns the previous ownership status of the entity for this process instance.
+ * @return true if this process was the owner of the entity at the time this notification was generated
+ */
+ public boolean wasOwner() {
+ return wasOwner;
+ }
+
+ /**
+ * Returns the current ownership status of the entity for this process instance.
+ * @return true if this process is now the owner of the entity
+ */
+ public boolean isOwner() {
+ return isOwner;
+ }
+
+ /**
+ * Returns the current ownership status of the entity across all process instances.
+ * @return true if the entity has an owner which may or may not be this process. If false, then
+ * the entity has no candidates and thus no owner.
+ */
+ public boolean hasOwner() {
+ return hasOwner;
+ }
+
+ @Override
+ public String toString() {
+ return name() + " [wasOwner=" + wasOwner + ", isOwner=" + isOwner + ", hasOwner=" + hasOwner + "]";
+ }
+
+ public static EntityOwnershipChangeState from(boolean wasOwner, boolean isOwner, boolean hasOwner) {
+ EntityOwnershipChangeState state = BY_KEY.get(new Key(wasOwner, isOwner, hasOwner));
+ Preconditions.checkArgument(state != null, "Invalid combination of wasOwner: %s, isOwner: %s, hasOwner: %s",
+ wasOwner, isOwner, hasOwner);
+ return state;
+ }
+
+ private static final class Key {
+ private final boolean wasOwner;
+ private final boolean isOwner;
+ private final boolean hasOwner;
+
+ Key(boolean wasOwner, boolean isOwner, boolean hasOwner) {
+ this.wasOwner = wasOwner;
+ this.isOwner = isOwner;
+ this.hasOwner = hasOwner;
+ }
+
+ @Override
+ public int hashCode() {
+ final int prime = 31;
+ int result = 1;
+ result = prime * result + (hasOwner ? 1231 : 1237);
+ result = prime * result + (isOwner ? 1231 : 1237);
+ result = prime * result + (wasOwner ? 1231 : 1237);
+ return result;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ Key other = (Key) obj;
+ return hasOwner == other.hasOwner && isOwner == other.isOwner && wasOwner == other.wasOwner;
+ }
+ }
+}