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.storm.localizer; import com.google.common.annotations.VisibleForTesting; import java.nio.file.Path; import java.util.concurrent.ConcurrentHashMap; import org.apache.commons.io.FileUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.File; import java.io.IOException; import java.nio.file.Files; import java.util.Comparator; import java.util.Iterator; import java.util.Map; import java.util.SortedMap; import java.util.TreeMap; /** * A set of resources that we can look at to see which ones we retain and which ones should be * removed. */ public class LocalizedResourceRetentionSet { public static final Logger LOG = LoggerFactory.getLogger(LocalizedResourceRetentionSet.class); private long delSize; private long currentSize; // targetSize in Bytes private long targetSize; @VisibleForTesting final SortedMap<ComparableResource, CleanableResourceSet> noReferences; private int resourceCount = 0; LocalizedResourceRetentionSet(long targetSize) { this(targetSize, new LRUComparator()); } LocalizedResourceRetentionSet(long targetSize, Comparator<? super ComparableResource> cmp) { this(targetSize, new TreeMap<>(cmp)); } LocalizedResourceRetentionSet(long targetSize, SortedMap<ComparableResource, CleanableResourceSet> retain) { this.noReferences = retain; this.targetSize = targetSize; } // for testing protected int getSizeWithNoReferences() { return noReferences.size(); } protected void addResourcesForSet(Iterator<LocalizedResource> setIter, LocalizedResourceSet set) { CleanableLocalizedResourceSet cleanset = new CleanableLocalizedResourceSet(set); for (Iterator<LocalizedResource> iter = setIter; setIter.hasNext();) { LocalizedResource lrsrc = iter.next(); currentSize += lrsrc.getSize(); resourceCount++; if (lrsrc.getRefCount() > 0) { // always retain resources in use continue; } noReferences.put(new LocalizedBlobComparableResource(lrsrc), cleanset); } } public void addResources(LocalizedResourceSet set) { addResourcesForSet(set.getLocalFilesIterator(), set); addResourcesForSet(set.getLocalArchivesIterator(), set); } public void addResources(ConcurrentHashMap<String, LocallyCachedBlob> blobs) { CleanableLocalizedLocallyCachedBlob set = new CleanableLocalizedLocallyCachedBlob(blobs); for (LocallyCachedBlob b : blobs.values()) { currentSize += b.getSizeOnDisk(); resourceCount++; if (b.isUsed()) { // always retain resources in use continue; } LocallyCachedBlobComparableResource cb = new LocallyCachedBlobComparableResource(b); noReferences.put(cb, set); } } public void cleanup() { LOG.debug("cleanup target size: {} current size is: {}", targetSize, currentSize); for (Iterator<Map.Entry<ComparableResource, CleanableResourceSet>> i = noReferences.entrySet() .iterator(); currentSize - delSize > targetSize && i.hasNext();) { Map.Entry<ComparableResource, CleanableResourceSet> rsrc = i.next(); ComparableResource resource = rsrc.getKey(); CleanableResourceSet set = rsrc.getValue(); if (resource != null && set.remove(resource)) { if (set.deleteUnderlyingResource(resource)) { delSize += resource.getSize(); LOG.info("deleting: {} with size of: {}", resource.getNameForDebug(), resource.getSize()); i.remove(); } else { // since it failed to delete add it back so it gets retried set.add(resource.getKey(), resource); } } } } @VisibleForTesting public boolean deleteResource(CleanableResourceSet set, ComparableResource resource) { return set.deleteUnderlyingResource(resource); } public long getCurrentSize() { return currentSize; } public int getResourceCount() { return resourceCount; } @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("Cache: ").append(currentSize).append(", "); sb.append("Deleted: ").append(delSize); return sb.toString(); } interface ComparableResource { long getLastAccessTime(); long getSize(); String getNameForDebug(); String getKey(); } interface CleanableResourceSet { boolean remove(ComparableResource resource); void add(String key, ComparableResource resource); boolean deleteUnderlyingResource(ComparableResource resource); } public static class LocallyCachedBlobComparableResource implements ComparableResource { private final LocallyCachedBlob blob; public LocallyCachedBlobComparableResource(LocallyCachedBlob blob) { this.blob = blob; } @Override public long getLastAccessTime() { return blob.getLastUsed(); } @Override public long getSize() { return blob.getSizeOnDisk(); } @Override public String getNameForDebug() { return blob.getKey(); } @Override public String getKey() { return blob.getKey(); } @Override public String toString() { return blob.toString(); } @Override public boolean equals(Object other) { if (other instanceof LocallyCachedBlobComparableResource) { return blob.equals(((LocallyCachedBlobComparableResource) other).blob); } return false; } @Override public int hashCode() { return blob.hashCode(); } } private static class CleanableLocalizedLocallyCachedBlob implements CleanableResourceSet { private final ConcurrentHashMap<String, LocallyCachedBlob> blobs; public CleanableLocalizedLocallyCachedBlob(ConcurrentHashMap<String, LocallyCachedBlob> blobs) { this.blobs = blobs; } @Override public boolean remove(ComparableResource resource) { if (!(resource instanceof LocallyCachedBlobComparableResource)) { throw new IllegalStateException(resource + " must be a LocallyCachedBlobComparableResource"); } LocallyCachedBlob blob = ((LocallyCachedBlobComparableResource) resource).blob; synchronized (blob) { if (!blob.isUsed()) { try { blob.completelyRemove(); } catch (Exception e) { LOG.warn("Tried to remove {} but failed with", blob, e); } blobs.remove(blob.getKey()); return true; } return false; } } @Override public void add(String key, ComparableResource resource) { ///NOOP not used } @Override public boolean deleteUnderlyingResource(ComparableResource resource) { //NOOP not used return true; } } private static class LocalizedBlobComparableResource implements ComparableResource { private final LocalizedResource resource; private LocalizedBlobComparableResource(LocalizedResource resource) { this.resource = resource; } @Override public long getLastAccessTime() { return resource.getLastAccessTime(); } @Override public long getSize() { return resource.getSize(); } @Override public String getNameForDebug() { return resource.getFilePath(); } @Override public String getKey() { return resource.getKey(); } @Override public String toString() { return resource.getKey() + " at " + resource.getFilePathWithVersion(); } @Override public boolean equals(Object other) { if (other instanceof LocalizedBlobComparableResource) { return resource.equals(((LocalizedBlobComparableResource) other).resource); } return false; } @Override public int hashCode() { return resource.hashCode(); } } private static class CleanableLocalizedResourceSet implements CleanableResourceSet { private final LocalizedResourceSet set; public CleanableLocalizedResourceSet(LocalizedResourceSet set) { this.set = set; } @Override public boolean remove(ComparableResource resource) { if (!(resource instanceof LocalizedBlobComparableResource)) { throw new IllegalStateException(resource + " must be a LocalizedBlobComparableResource"); } return set.remove(((LocalizedBlobComparableResource) resource).resource); } @Override public void add(String key, ComparableResource resource) { if (!(resource instanceof LocalizedBlobComparableResource)) { throw new IllegalStateException(resource + " must be a LocalizedBlobComparableResource"); } LocalizedResource r = ((LocalizedBlobComparableResource) resource).resource; set.add(key, r, r.isUncompressed()); } @Override public boolean deleteUnderlyingResource(ComparableResource resource) { if (resource instanceof LocalizedBlobComparableResource) { LocalizedResource lr = ((LocalizedBlobComparableResource) resource).resource; try { Path fileWithVersion = new File(lr.getFilePathWithVersion()).toPath(); Path currentSymLink = new File(lr.getCurrentSymlinkPath()).toPath(); Path versionFile = new File(lr.getVersionFilePath()).toPath(); if (lr.isUncompressed()) { if (Files.exists(fileWithVersion)) { // this doesn't follow symlinks, which is what we want FileUtils.deleteDirectory(fileWithVersion.toFile()); } } else { Files.deleteIfExists(fileWithVersion); } Files.deleteIfExists(currentSymLink); Files.deleteIfExists(versionFile); return true; } catch (IOException e) { LOG.warn("Could not delete: {}", resource.getNameForDebug(), e); } return false; } else { throw new IllegalArgumentException("Don't know how to handle a " + resource.getClass()); } } } static class LRUComparator implements Comparator<ComparableResource> { public int compare(ComparableResource r1, ComparableResource r2) { long ret = r1.getLastAccessTime() - r2.getLastAccessTime(); if (0 == ret) { return System.identityHashCode(r1) - System.identityHashCode(r2); } return ret > 0 ? 1 : -1; } } }