content: /*
   * 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.arrow.vector;
  
  import org.apache.arrow.vector.util.CallBack;
  
  /**
   * Callback for when the Schema for the Vector changes (generally happens when a vector is promoted
   * to a union type from a single value type).
   */
  public class SchemaChangeCallBack implements CallBack {
    private boolean schemaChanged = false;
  
    /** Constructs a schema-change callback with the schema-changed state set to {@code false}. */
    public SchemaChangeCallBack() {}
  
    /** Sets the schema-changed state to {@code true}. */
    @Override
    public void doWork() {
      schemaChanged = true;
    }
  
    /**
     * Returns the value of schema-changed state, <strong>resetting</strong> the schema-changed state
     * to {@code false}.
     *
     * @return the previous schema-changed state
     */
    public boolean getSchemaChangedAndReset() {
      final boolean current = schemaChanged;
      schemaChanged = false;
      return current;
    }
  }
  