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 026 * set of {@code Object}s. They provide convenience methods which handle 027 * type casting on your behalf. 028 */ 029@SuppressWarnings("unchecked") 030@InterfaceAudience.Public 031public abstract class Union2<A, B> implements DataType<Object> { 032 033 protected final DataType<A> typeA; 034 protected final DataType<B> typeB; 035 036 /** 037 * Create an instance of {@code Union2} over the set of specified 038 * types. 039 */ 040 public Union2(DataType<A> typeA, DataType<B> typeB) { 041 this.typeA = typeA; 042 this.typeB = typeB; 043 } 044 045 @Override 046 public boolean isOrderPreserving() { 047 return typeA.isOrderPreserving() && typeB.isOrderPreserving(); 048 } 049 050 @Override 051 public Order getOrder() { 052 return null; 053 } 054 055 @Override 056 public boolean isNullable() { 057 return typeA.isNullable() && typeB.isNullable(); 058 } 059 060 @Override 061 public boolean isSkippable() { 062 return typeA.isSkippable() && typeB.isSkippable(); 063 } 064 065 @Override 066 public Class<Object> encodedClass() { 067 throw new UnsupportedOperationException( 068 "Union types do not expose a definitive encoded class."); 069 } 070 071 /** 072 * Read an instance of the first type parameter from buffer {@code src}. 073 */ 074 public A decodeA(PositionedByteRange src) { 075 return (A) decode(src); 076 } 077 078 /** 079 * Read an instance of the second type parameter from buffer {@code src}. 080 */ 081 public B decodeB(PositionedByteRange src) { 082 return (B) decode(src); 083 } 084}