HBASE-25793 Move BaseLoadBalancer.Cluster to a separated file (#3185)

Signed-off-by: Yulin Niu <[email protected]>

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/AssignRegionAction.java

@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hadoop.hbase.master.balancer;
+
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.yetus.audience.InterfaceAudience;
+
+@InterfaceAudience.Private
+class AssignRegionAction extends BalanceAction {
+  private final int region;
+  private final int server;
+
+  public AssignRegionAction(int region, int server) {
+    super(Type.ASSIGN_REGION);
+    this.region = region;
+    this.server = server;
+  }
+
+  public int getRegion() {
+    return region;
+  }
+
+  public int getServer() {
+    return server;
+  }
+
+  @Override
+  public BalanceAction undoAction() {
+    // TODO implement this. This action is not being used by the StochasticLB for now
+    // in case it uses it, we should implement this function.
+    throw new UnsupportedOperationException(HConstants.NOT_IMPLEMENTED);
+  }
+
+  @Override
+  public String toString() {
+    return getType() + ": " + region + ":" + server;
+  }
+
+}

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/BalanceAction.java

@@ -0,0 +1,55 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hadoop.hbase.master.balancer;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * An action to move or swap a region
+ */
+@InterfaceAudience.Private
+abstract class BalanceAction {
+  enum Type {
+    ASSIGN_REGION, MOVE_REGION, SWAP_REGIONS, NULL,
+  }
+
+  static final BalanceAction NULL_ACTION = new BalanceAction(Type.NULL) {
+  };
+
+  private final Type type;
+
+  BalanceAction(Type type) {
+    this.type = type;
+  }
+
+  /**
+   * Returns an Action which would undo this action
+   */
+  BalanceAction undoAction() {
+    return this;
+  }
+
+  Type getType() {
+    return type;
+  }
+
+  @Override
+  public String toString() {
+    return type + ":";
+  }
+}