virajjasani commented on a change in pull request #1818: URL: https://github.com/apache/hbase/pull/1818#discussion_r433243909
########## File path: hbase-client/src/main/java/org/apache/hadoop/hbase/client/ImmutableScan.java ########## @@ -0,0 +1,477 @@ +/* + * + * 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.client; + +import java.io.IOException; +import java.util.Collections; +import java.util.Map; +import java.util.NavigableSet; +import org.apache.hadoop.hbase.filter.Filter; +import org.apache.hadoop.hbase.io.TimeRange; +import org.apache.hadoop.hbase.security.access.Permission; +import org.apache.hadoop.hbase.security.visibility.Authorizations; +import org.apache.yetus.audience.InterfaceAudience; + +/** + * Immutable version of Scan + */ [email protected] +public final class ImmutableScan extends Scan { + + /** + * Create Immutable instance of Scan from given Scan object + * + * @param scan Copy all values from Scan + * @throws IOException From parent constructor + */ + public ImmutableScan(Scan scan) throws IOException { + super(scan); + super.setIsolationLevel(scan.getIsolationLevel()); + Map<byte[], NavigableSet<byte[]>> familyMap = scan.getFamilyMap(); + for (Map.Entry<byte[], NavigableSet<byte[]>> entry : familyMap.entrySet()) { + byte[] family = entry.getKey(); + NavigableSet<byte[]> cols = entry.getValue(); + if (cols != null && cols.size() > 0) { + for (byte[] col : cols) { + super.addColumn(family, col); + } + } else { + super.addFamily(family); + } + } + for (Map.Entry<String, byte[]> attr : scan.getAttributesMap().entrySet()) { + super.setAttribute(attr.getKey(), attr.getValue()); + } + for (Map.Entry<byte[], TimeRange> entry : scan.getColumnFamilyTimeRange().entrySet()) { + TimeRange tr = entry.getValue(); + super.setColumnFamilyTimeRange(entry.getKey(), tr.getMin(), tr.getMax()); + } + super.setPriority(scan.getPriority()); + } + + /** + * Create Immutable instance of Scan from given Get object + * + * @param get Get to model Scan after + */ + public ImmutableScan(Get get) { + super(get); + super.setIsolationLevel(get.getIsolationLevel()); + for (Map.Entry<String, byte[]> attr : get.getAttributesMap().entrySet()) { + super.setAttribute(attr.getKey(), attr.getValue()); + } + for (Map.Entry<byte[], TimeRange> entry : get.getColumnFamilyTimeRange().entrySet()) { + TimeRange tr = entry.getValue(); + super.setColumnFamilyTimeRange(entry.getKey(), tr.getMin(), tr.getMax()); + } + super.setPriority(get.getPriority()); + } + + /** + * Create a new Scan with a cursor. It only set the position information like start row key. + * The others (like cfs, stop row, limit) should still be filled in by the user. + * {@link Result#isCursor()} + * {@link Result#getCursor()} + * {@link Cursor} + */ + public static Scan createScanFromCursor(Cursor cursor) { Review comment: @anoopsjohn `isObjInit` is for different purpose. When we call parent `Scan` constructors, they call few setter methods. And ImmutableScan is not supposed to support setter methods, but this time object is getting initialized and hence, we need to allow it. e.g. ``` public Scan addFamily(byte[] family) { if (!isObjInit) { return super.addFamily(family); } throw new UnsupportedOperationException("ImmutableScan does not allow access to addFamily"); } ``` Here, `addFamily` is being called by Scan constructor which is called by ImmutableScan as part of super call. However, when Scan constructor calls `addFamily`, the control goes to the implementation provided in child class ImmutableScan. Now, ImmutableScan will throw `UnsupportedOperationException` saying we don't allow setter calls. Hence, I had to introduce `isObjInit` which is set to true only after super constructor calls, which means setter methods will call corresponding parent setter methods if object is being initialized, and once it is initialized, all setters will throw `UnsupportedOperationException`. Please check my recent commit: https://github.com/apache/hbase/pull/1818/commits/a075e17f2dcf128e11d05de2630249fc3048de49 You will get the idea of what kind of hack I had to do in parent class to avoid calling child class methods :) ---------------------------------------------------------------- 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]
