Java tutorial
/** * 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.distributedlog.impl.logsegment; import com.google.common.collect.Lists; import java.util.List; import java.util.concurrent.CompletableFuture; import org.apache.bookkeeper.client.AsyncCallback; import org.apache.bookkeeper.client.BKException; import org.apache.bookkeeper.client.LedgerHandle; import org.apache.bookkeeper.common.concurrent.FutureUtils; import org.apache.distributedlog.common.functions.VoidFunctions; /** * BookKeeper Util Functions. */ public class BKUtils { /** * Close a ledger <i>lh</i>. * * @param lh ledger handle * @return future represents close result. */ public static CompletableFuture<Void> closeLedger(LedgerHandle lh) { final CompletableFuture<Void> closePromise = new CompletableFuture<Void>(); lh.asyncClose(new AsyncCallback.CloseCallback() { @Override public void closeComplete(int rc, LedgerHandle lh, Object ctx) { if (BKException.Code.OK != rc) { FutureUtils.completeExceptionally(closePromise, BKException.create(rc)); } else { FutureUtils.complete(closePromise, null); } } }, null); return closePromise; } /** * Close a list of ledgers <i>lhs</i>. * * @param lhs a list of ledgers * @return future represents close results. */ public static CompletableFuture<Void> closeLedgers(LedgerHandle... lhs) { List<CompletableFuture<Void>> closeResults = Lists.newArrayListWithExpectedSize(lhs.length); for (LedgerHandle lh : lhs) { closeResults.add(closeLedger(lh)); } return FutureUtils.collect(closeResults).thenApply(VoidFunctions.LIST_TO_VOID_FUNC); } }