yurinaryshkin commented on code in PR #10798: URL: https://github.com/apache/ignite/pull/10798#discussion_r1251730293
########## modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/wal/WalRecordsIteratorAdaptor.java: ########## @@ -0,0 +1,104 @@ +/* + * 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.ignite.internal.processors.cache.persistence.wal; + +import java.util.Optional; +import org.apache.ignite.IgniteCheckedException; +import org.apache.ignite.IgniteLogger; +import org.apache.ignite.internal.pagemem.wal.WALIterator; +import org.apache.ignite.internal.pagemem.wal.record.WALRecord; +import org.apache.ignite.internal.util.GridCloseableIteratorAdapter; +import org.apache.ignite.lang.IgniteBiTuple; +import org.jetbrains.annotations.NotNull; + +/** + * Iterator over WAL segments. This abstract class provides most functionality for reading records. + */ +public abstract class WalRecordsIteratorAdaptor + extends GridCloseableIteratorAdapter<IgniteBiTuple<WALPointer, WALRecord>> implements WALIterator { + /** */ + private static final long serialVersionUID = 0L; + + /** + * Current record preloaded, to be returned on next()<br> Normally this should be not null because advance() method + * should already prepare some value<br> + */ + protected IgniteBiTuple<WALPointer, WALRecord> curRec; + + /** + * The exception which can be thrown during reading next record. It holds until the next calling of next record. + */ + private IgniteCheckedException curException; + + /** Logger */ + @NotNull protected final IgniteLogger log; + + /** Position of last read valid record. */ + private WALPointer lastRead; + + /** + * @param log Logger. + */ + protected WalRecordsIteratorAdaptor(@NotNull final IgniteLogger log) { + this.log = log; + } + + /** {@inheritDoc} */ + @Override protected IgniteBiTuple<WALPointer, WALRecord> onNext() throws IgniteCheckedException { + if (curException != null) + throw curException; + + IgniteBiTuple<WALPointer, WALRecord> ret = curRec; + + try { + advance(); + } + catch (IgniteCheckedException e) { + curException = e; + } + + return ret; + } + + /** {@inheritDoc} */ + @Override protected boolean onHasNext() throws IgniteCheckedException { + if (curException != null) + throw curException; + + return curRec != null; + } + + /** + * Switches records iterator to the next record. <ul> <li>{@link #curRec} will be updated.</li> </ul> + * + * {@code advance()} runs a step ahead {@link #next()} + * + * @throws IgniteCheckedException If failed. + */ + protected abstract void advance() throws IgniteCheckedException; + + /** {@inheritDoc} */ + @Override public Optional<WALPointer> lastRead() { + return Optional.ofNullable(lastRead); + } + + /** */ + protected void lastRead(WALPointer lastRead) { Review Comment: Moved the lastRead setting logic into advance method, so that it will be set just before returning the value to caller. -- 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]
