ceph/src/arrow/java/vector/src/main/java/org/apache/arrow/vector/SchemaChangeCallBack.java

   1 /*
   2  * Licensed to the Apache Software Foundation (ASF) under one or more
   3  * contributor license agreements.  See the NOTICE file distributed with
   4  * this work for additional information regarding copyright ownership.
   5  * The ASF licenses this file to You under the Apache License, Version 2.0
   6  * (the "License"); you may not use this file except in compliance with
   7  * the License.  You may obtain a copy of the License at
   8  *
   9  *    http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 package org.apache.arrow.vector;
  19
  20 import org.apache.arrow.vector.util.CallBack;
  21
  22
  23 /**
  24  * Callback for when the Schema for the Vector changes (generally happens when a vector is promoted to a union type
  25  * from a single value type).
  26  */
  27 public class SchemaChangeCallBack implements CallBack {
  28   private boolean schemaChanged = false;
  29
  30   /**
  31    * Constructs a schema-change callback with the schema-changed state set to
  32    * {@code false}.
  33    */
  34   public SchemaChangeCallBack() {
  35   }
  36
  37   /**
  38    * Sets the schema-changed state to {@code true}.
  39    */
  40   @Override
  41   public void doWork() {
  42     schemaChanged = true;
  43   }
  44
  45   /**
  46    * Returns the value of schema-changed state, <strong>resetting</strong> the
  47    * schema-changed state to {@code false}.
  48    *
  49    * @return the previous schema-changed state
  50    */
  51   public boolean getSchemaChangedAndReset() {
  52     final boolean current = schemaChanged;
  53     schemaChanged = false;
  54     return current;
  55   }
  56 }
  57