anoopsjohn commented on a change in pull request #2707: URL: https://github.com/apache/hbase/pull/2707#discussion_r537231625
########## File path: hbase-common/src/main/java/org/apache/hadoop/hbase/TagBuilderFactory.java ########## @@ -0,0 +1,89 @@ +/** + * Copyright The Apache Software Foundation + * + * 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; + +import java.nio.ByteBuffer; +import org.apache.yetus.audience.InterfaceAudience; + +/** + * Factory to create Tags. + */ [email protected](HBaseInterfaceAudience.COPROC) +public final class TagBuilderFactory { + + public static TagBuilder create() { + return new TagBuilderImpl(); + } +} + +/** + * Builder implementation to create either {@link ArrayBackedTag} or {@link ByteBufferTag}<br> + * Call setTagValue(byte[]) method if you want to create {@link ArrayBackedTag} or + * call setTagValue(ByteBuffer) if you want to create {@link ByteBufferTag} + */ +class TagBuilderImpl implements TagBuilder { + // This assumes that we never create tag with value less than 0. + private byte tagType = (byte)-1; + private byte[] tagBytes = null; + private ByteBuffer tagBuffer = null; + public static final String TAG_TYPE_NOT_SET_EXCEPTION = "Need to set type of the tag."; + public static final String TAG_VALUE_NULL_EXCEPTION = + "Both tagBytes and tagBuffer can't be null"; + + @Override + public TagBuilder setTagType(byte tagType) { + this.tagType = tagType; + return this; + } + + @Override + public TagBuilder setTagValue(byte[] tagBytes) { + this.tagBytes = tagBytes; + this.tagBuffer = null; + return this; + } + + @Override + public TagBuilder setTagValue(ByteBuffer value) { + this.tagBuffer = value; + this.tagBytes = null; + return this; + } + + private void validate() { + if (tagType == -1) { + throw new IllegalArgumentException(TAG_TYPE_NOT_SET_EXCEPTION); + } + if (tagBytes == null && tagBuffer == null) { + throw new IllegalArgumentException(TAG_VALUE_NULL_EXCEPTION); + } + } + + @Override + public Tag build() { + validate(); + if (tagBytes != null) { + return new ArrayBackedTag(tagType, tagBytes); + } else { + return new ByteBufferTag(tagType, tagBuffer, -Tag.INFRASTRUCTURE_SIZE, Review comment: I see. So by keeping the offset as -3, we make the logic in ByteBufferTag to work when type and length is not part of backing BB. Looks hacky no? Do we really need some one to create Tag backed by BB? Why some one would like to do that. We created the BB backed Tag impl as a ready only impl where the HFileBlock data is already backed by BB. Just for reading tags we did not want to create byte[] and copy them. So its an internal HBase thing. When CP wants to create tags then also, we can restrict to array backed only IMHO. So changed to BB backed Tag we can really avoid and keep it simple. Also we can clearly mention in BB backed tag as a code level comments or so. WDYT? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
