001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.types;
019
020import org.apache.hadoop.hbase.util.Order;
021import org.apache.hadoop.hbase.util.PositionedByteRange;
022import org.apache.yetus.audience.InterfaceAudience;
023
024/**
025 * The {@code Union} family of {@link DataType}s encode one of a fixed set of {@code Object}s. They
026 * provide convenience methods which handle type casting on your behalf.
027 */
028@SuppressWarnings("unchecked")
029@InterfaceAudience.Public
030public abstract class Union2<A, B> implements DataType<Object> {
031
032  protected final DataType<A> typeA;
033  protected final DataType<B> typeB;
034
035  /**
036   * Create an instance of {@code Union2} over the set of specified types.
037   */
038  public Union2(DataType<A> typeA, DataType<B> typeB) {
039    this.typeA = typeA;
040    this.typeB = typeB;
041  }
042
043  @Override
044  public boolean isOrderPreserving() {
045    return typeA.isOrderPreserving() && typeB.isOrderPreserving();
046  }
047
048  @Override
049  public Order getOrder() {
050    return null;
051  }
052
053  @Override
054  public boolean isNullable() {
055    return typeA.isNullable() && typeB.isNullable();
056  }
057
058  @Override
059  public boolean isSkippable() {
060    return typeA.isSkippable() && typeB.isSkippable();
061  }
062
063  @Override
064  public Class<Object> encodedClass() {
065    throw new UnsupportedOperationException(
066      "Union types do not expose a definitive encoded class.");
067  }
068
069  /**
070   * Read an instance of the first type parameter from buffer {@code src}.
071   */
072  public A decodeA(PositionedByteRange src) {
073    return (A) decode(src);
074  }
075
076  /**
077   * Read an instance of the second type parameter from buffer {@code src}.
078   */
079  public B decodeB(PositionedByteRange src) {
080    return (B) decode(src);
081  }
082}