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.cassandra.utils; import java.io.File; import java.io.IOException; import java.nio.file.FileVisitResult; import java.nio.file.Path; import java.nio.file.SimpleFileVisitor; import java.nio.file.attribute.BasicFileAttributes; import java.util.List; import java.util.Set; import java.util.concurrent.atomic.AtomicLong; import com.google.common.collect.ImmutableSet; import static com.google.common.collect.Sets.newHashSet; /** * Walks directory recursively, summing up total contents of files within. */ public class DirectorySizeCalculator extends SimpleFileVisitor<Path> { protected final AtomicLong size = new AtomicLong(0); protected Set<String> visited = newHashSet(); //count each file only once protected Set<String> alive = newHashSet(); protected final File path; public DirectorySizeCalculator(File path) { super(); this.path = path; rebuildFileList(); } public DirectorySizeCalculator(List<File> files) { super(); this.path = null; ImmutableSet.Builder<String> builder = ImmutableSet.builder(); for (File file : files) builder.add(file.getName()); alive = builder.build(); } public boolean isAcceptable(Path file) { return true; } public void rebuildFileList() { assert path != null; ImmutableSet.Builder<String> builder = ImmutableSet.builder(); for (File file : path.listFiles()) builder.add(file.getName()); size.set(0); alive = builder.build(); } @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { if (isAcceptable(file)) { size.addAndGet(attrs.size()); visited.add(file.toFile().getName()); } return FileVisitResult.CONTINUE; } @Override public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException { return FileVisitResult.CONTINUE; } public long getAllocatedSize() { return size.get(); } }