virajjasani commented on a change in pull request #1818: URL: https://github.com/apache/hbase/pull/1818#discussion_r433410406
########## 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 + */ +@InterfaceAudience.Public +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: We can have wrapper but providing Scan object (which is Immutable by nature) to coprocessor hooks sounds better. Even though we provide Scan object to store scanner coproc hooks, it is Immutable as per the use-case and that is something HBase can take care of. Moreover, dev adding new method to Scan are more likely to override it in ImmutableScan class because all methods are overridden(they can get IDE hints) but they are less likely to realize usage of each method in some wrapper class and add the method in wrapper. However, if we have better pros of using wrapper, I am fine with that also. Thoughts? ---------------------------------------------------------------- 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: us...@infra.apache.org
