kfaraz commented on a change in pull request #12269: URL: https://github.com/apache/druid/pull/12269#discussion_r822432410
########## File path: indexing-service/src/main/java/org/apache/druid/indexing/seekablestream/SettableByteEntity.java ########## @@ -0,0 +1,124 @@ +/* + * 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.druid.indexing.seekablestream; + +import com.google.common.base.Preconditions; +import org.apache.druid.data.input.InputEntity; +import org.apache.druid.data.input.impl.ByteEntity; +import org.apache.druid.io.ByteBufferInputStream; +import org.apache.druid.java.util.common.IAE; + +import javax.annotation.Nullable; +import javax.annotation.concurrent.NotThreadSafe; + +import java.io.InputStream; +import java.net.URI; +import java.nio.ByteBuffer; + +/** + * This class is only to be used with {@link SettableByteEntityReader} and {code KafkaInputFormat}. It is useful for stream + * processing where binary records are arriving as a list but {@link org.apache.druid.data.input.InputEntityReader}, that + * parses the data, expects an {@link InputStream}. This class mimics a continuous InputStream while behind the scenes, + * binary records are being put one after the other that the InputStream consumes bytes from. One record is fully + * consumed and only then the next record is set. This class doesn't allow reading the same data twice. + * This class solely exists to overcome the limitations imposed by interfaces for reading and parsing data. + * + */ +@NotThreadSafe +public class SettableByteEntity implements InputEntity +{ + private final SettableByteBufferInputStream inputStream; + private boolean opened = false; + private ByteEntity entity; + + public SettableByteEntity() + { + this.inputStream = new SettableByteBufferInputStream(); + } + + public void setEntity(ByteEntity entity) + { + inputStream.setBuffer(entity.getBuffer()); + this.entity = entity; + opened = false; + } + + @Nullable + @Override + public URI getUri() + { + return null; + } + + public ByteEntity getEntity() + { + return entity; + } + + /** + * This method can be called multiple times only for different data. So you can open a new input stream + * only after a new buffer is in use. + */ + @Override + public InputStream open() + { + if (opened) { + throw new IllegalArgumentException("Can't open the input stream on SettableByteEntity more than once"); + } + + opened = true; + return inputStream; + } + + public static final class SettableByteBufferInputStream extends InputStream + { + @Nullable + private ByteBufferInputStream delegate; + + public void setBuffer(ByteBuffer newBuffer) + { + if (null != delegate && available() > 0) { + throw new IAE("New data cannot be set in buffer till all the old data has been read"); + } + this.delegate = new ByteBufferInputStream(newBuffer); + } + + @Override + public int read() + { + Preconditions.checkNotNull(delegate, "Buffet is not set"); Review comment: Nit: ```suggestion Preconditions.checkNotNull(delegate, "Buffer is not set"); ``` Hope, it wasn't on purpose! 😂 -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
