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The Core Camel Java DSL based router
/**
* 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.camel.processor.idempotent;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.camel.api.management.ManagedAttribute;
import org.apache.camel.api.management.ManagedOperation;
import org.apache.camel.api.management.ManagedResource;
import org.apache.camel.spi.IdempotentRepository;
import org.apache.camel.support.ServiceSupport;
import org.apache.camel.util.FileUtil;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.LRUCache;
import org.apache.camel.util.LRUCacheFactory;
import org.apache.camel.util.ObjectHelper;
import org.apache.camel.util.Scanner;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A file based implementation of {@link org.apache.camel.spi.IdempotentRepository}.
*
* This implementation provides a 1st-level in-memory {@link LRUCache} for fast check of the most
* frequently used keys. When {@link #add(String)} or {@link #contains(String)} methods are being used
* then in case of 1st-level cache miss, the underlying file is scanned which may cost additional performance.
* So try to find the right balance of the size of the 1st-level cache, the default size is 1000.
* The file store has a maximum capacity of 32mb by default (you can turn this off and have unlimited size).
* If the file store grows bigger than the maximum capacity, then the {@link #getDropOldestFileStore()} (is default 1000)
* number of entries from the file store is dropped to reduce the file store and make room for newer entries.
*
* @version
*/
@ManagedResource(description = "File based idempotent repository")
public class FileIdempotentRepository extends ServiceSupport implements IdempotentRepository {
private static final Logger LOG = LoggerFactory.getLogger(FileIdempotentRepository.class);
private static final String STORE_DELIMITER = "\n";
private final AtomicBoolean init = new AtomicBoolean();
private Map cache;
private File fileStore;
private long maxFileStoreSize = 32 * 1024 * 1000L; // 32mb store file
private long dropOldestFileStore = 1000;
public FileIdempotentRepository() {
}
public FileIdempotentRepository(File fileStore, Map set) {
this.fileStore = fileStore;
this.cache = set;
}
/**
* Creates a new file based repository using a {@link org.apache.camel.util.LRUCache}
* as 1st level cache with a default of 1000 entries in the cache.
*
* @param fileStore the file store
*/
public static IdempotentRepository fileIdempotentRepository(File fileStore) {
return fileIdempotentRepository(fileStore, 1000);
}
/**
* Creates a new file based repository using a {@link org.apache.camel.util.LRUCache}
* as 1st level cache.
*
* @param fileStore the file store
* @param cacheSize the cache size
*/
@SuppressWarnings("unchecked")
public static IdempotentRepository fileIdempotentRepository(File fileStore, int cacheSize) {
return fileIdempotentRepository(fileStore, LRUCacheFactory.newLRUCache(cacheSize));
}
/**
* Creates a new file based repository using a {@link org.apache.camel.util.LRUCache}
* as 1st level cache.
*
* @param fileStore the file store
* @param cacheSize the cache size
* @param maxFileStoreSize the max size in bytes for the filestore file
*/
@SuppressWarnings("unchecked")
public static IdempotentRepository fileIdempotentRepository(File fileStore, int cacheSize, long maxFileStoreSize) {
FileIdempotentRepository repository = new FileIdempotentRepository(fileStore, LRUCacheFactory.newLRUCache(cacheSize));
repository.setMaxFileStoreSize(maxFileStoreSize);
return repository;
}
/**
* Creates a new file based repository using the given {@link java.util.Map}
* as 1st level cache.
*
* Care should be taken to use a suitable underlying {@link java.util.Map} to avoid this class being a
* memory leak.
*
* @param store the file store
* @param cache the cache to use as 1st level cache
*/
public static IdempotentRepository fileIdempotentRepository(File store, Map cache) {
return new FileIdempotentRepository(store, cache);
}
@ManagedOperation(description = "Adds the key to the store")
public boolean add(String key) {
synchronized (cache) {
if (cache.containsKey(key)) {
return false;
} else {
// always register the most used keys in the LRUCache
cache.put(key, key);
// now check the file store
boolean containsInFile = containsStore(key);
if (containsInFile) {
return false;
}
// its a new key so append to file store
appendToStore(key);
// check if we hit maximum capacity (if enabled) and report a warning about this
if (maxFileStoreSize > 0 && fileStore.length() > maxFileStoreSize) {
LOG.warn("Maximum capacity of file store: {} hit at {} bytes. Dropping {} oldest entries from the file store", fileStore, maxFileStoreSize, dropOldestFileStore);
trunkStore();
}
return true;
}
}
}
@ManagedOperation(description = "Does the store contain the given key")
public boolean contains(String key) {
synchronized (cache) {
// check 1st-level first and then fallback to check the actual file
return cache.containsKey(key) || containsStore(key);
}
}
@ManagedOperation(description = "Remove the key from the store")
public boolean remove(String key) {
boolean answer;
synchronized (cache) {
answer = cache.remove(key) != null;
// remove from file cache also
removeFromStore(key);
}
return answer;
}
public boolean confirm(String key) {
// noop
return true;
}
@ManagedOperation(description = "Clear the store (danger this removes all entries)")
public void clear() {
synchronized (cache) {
cache.clear();
if (cache instanceof LRUCache) {
((LRUCache) cache).cleanUp();
}
// clear file store
clearStore();
}
}
public File getFileStore() {
return fileStore;
}
public void setFileStore(File fileStore) {
this.fileStore = fileStore;
}
@ManagedAttribute(description = "The file path for the store")
public String getFilePath() {
return fileStore.getPath();
}
public Map getCache() {
return cache;
}
public void setCache(Map cache) {
this.cache = cache;
}
@ManagedAttribute(description = "The maximum file size for the file store in bytes")
public long getMaxFileStoreSize() {
return maxFileStoreSize;
}
/**
* Sets the maximum file size for the file store in bytes.
* You can set the value to 0 or negative to turn this off, and have unlimited file store size.
*
* The default is 32mb.
*/
@ManagedAttribute(description = "The maximum file size for the file store in bytes")
public void setMaxFileStoreSize(long maxFileStoreSize) {
this.maxFileStoreSize = maxFileStoreSize;
}
public long getDropOldestFileStore() {
return dropOldestFileStore;
}
/**
* Sets the number of oldest entries to drop from the file store when the maximum capacity is hit to reduce
* disk space to allow room for new entries.
*
* The default is 1000.
*/
@ManagedAttribute(description = "Number of oldest elements to drop from file store if maximum file size reached")
public void setDropOldestFileStore(long dropOldestFileStore) {
this.dropOldestFileStore = dropOldestFileStore;
}
/**
* Sets the 1st-level cache size.
*
* Setting cache size is only possible when using the default {@link LRUCache} cache implementation.
*/
@SuppressWarnings("unchecked")
public void setCacheSize(int size) {
if (cache != null && !(cache instanceof LRUCache)) {
throw new IllegalArgumentException("Setting cache size is only possible when using the default LRUCache cache implementation");
}
if (cache != null) {
cache.clear();
}
cache = LRUCacheFactory.newLRUCache(size);
}
@ManagedAttribute(description = "The current 1st-level cache size")
public int getCacheSize() {
if (cache != null) {
return cache.size();
}
return 0;
}
/**
* Reset and clears the 1st-level cache to force it to reload from file
*/
@ManagedOperation(description = "Reset and reloads the file store")
public synchronized void reset() throws IOException {
synchronized (cache) {
// run the cleanup task first
if (cache instanceof LRUCache) {
((LRUCache) cache).cleanUp();
}
cache.clear();
loadStore();
}
}
/**
* Checks the file store if the key exists
*
* @param key the key
* @return true if exists in the file, false otherwise
*/
protected boolean containsStore(final String key) {
if (fileStore == null || !fileStore.exists()) {
return false;
}
try (Scanner scanner = new Scanner(fileStore, null, STORE_DELIMITER)) {
while (scanner.hasNext()) {
String line = scanner.next();
if (line.equals(key)) {
return true;
}
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
}
return false;
}
/**
* Appends the given key to the file store
*
* @param key the key
*/
protected void appendToStore(final String key) {
LOG.debug("Appending: {} to idempotent filestore: {}", key, fileStore);
FileOutputStream fos = null;
try {
// create store parent directory if missing
File storeParentDirectory = fileStore.getParentFile();
if (storeParentDirectory != null && !storeParentDirectory.exists()) {
LOG.info("Parent directory of file store {} doesn't exist. Creating.", fileStore);
if (fileStore.getParentFile().mkdirs()) {
LOG.info("Parent directory of filestore: {} successfully created.", fileStore);
} else {
LOG.warn("Parent directory of filestore: {} cannot be created.", fileStore);
}
}
// create store if missing
if (!fileStore.exists()) {
FileUtil.createNewFile(fileStore);
}
// append to store
fos = new FileOutputStream(fileStore, true);
fos.write(key.getBytes());
fos.write(STORE_DELIMITER.getBytes());
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
} finally {
IOHelper.close(fos, "Appending to file idempotent repository", LOG);
}
}
protected synchronized void removeFromStore(String key) {
LOG.debug("Removing: {} from idempotent filestore: {}", key, fileStore);
// we need to re-load the entire file and remove the key and then re-write the file
List lines = new ArrayList<>();
boolean found = false;
Scanner scanner = null;
try {
scanner = new Scanner(fileStore, null, STORE_DELIMITER);
while (scanner.hasNext()) {
String line = scanner.next();
if (key.equals(line)) {
found = true;
} else {
lines.add(line);
}
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
} finally {
if (scanner != null) {
scanner.close();
}
}
if (found) {
// rewrite file
LOG.debug("Rewriting idempotent filestore: {} due to key: {} removed", fileStore, key);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(fileStore);
for (String line : lines) {
fos.write(line.getBytes());
fos.write(STORE_DELIMITER.getBytes());
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
} finally {
IOHelper.close(fos, "Rewriting file idempotent repository", LOG);
}
}
}
/**
* Clears the file-store (danger this deletes all entries)
*/
protected void clearStore() {
try {
FileUtil.deleteFile(fileStore);
FileUtil.createNewFile(fileStore);
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
}
}
/**
* Trunks the file store when the max store size is hit by dropping the most oldest entries.
*/
protected synchronized void trunkStore() {
if (fileStore == null || !fileStore.exists()) {
return;
}
LOG.debug("Trunking: {} oldest entries from idempotent filestore: {}", dropOldestFileStore, fileStore);
// we need to re-load the entire file and remove the key and then re-write the file
List lines = new ArrayList<>();
Scanner scanner = null;
int count = 0;
try {
scanner = new Scanner(fileStore, null, STORE_DELIMITER);
while (scanner.hasNext()) {
String line = scanner.next();
count++;
if (count > dropOldestFileStore) {
lines.add(line);
}
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
} finally {
if (scanner != null) {
scanner.close();
}
}
if (!lines.isEmpty()) {
// rewrite file
LOG.debug("Rewriting idempotent filestore: {} with {} entries:", fileStore, lines.size());
FileOutputStream fos = null;
try {
fos = new FileOutputStream(fileStore);
for (String line : lines) {
fos.write(line.getBytes());
fos.write(STORE_DELIMITER.getBytes());
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
} finally {
IOHelper.close(fos, "Rewriting file idempotent repository", LOG);
}
} else {
// its a small file so recreate the file
LOG.debug("Clearing idempotent filestore: {}", fileStore);
clearStore();
}
}
/**
* Cleanup the 1st-level cache.
*/
protected void cleanup() {
// run the cleanup task first
if (cache instanceof LRUCache) {
((LRUCache) cache).cleanUp();
}
}
/**
* Loads the given file store into the 1st level cache
*/
protected void loadStore() throws IOException {
// auto create starting directory if needed
if (!fileStore.exists()) {
LOG.debug("Creating filestore: {}", fileStore);
File parent = fileStore.getParentFile();
if (parent != null) {
parent.mkdirs();
}
boolean created = FileUtil.createNewFile(fileStore);
if (!created) {
throw new IOException("Cannot create filestore: " + fileStore);
}
}
LOG.trace("Loading to 1st level cache from idempotent filestore: {}", fileStore);
cache.clear();
try (Scanner scanner = new Scanner(fileStore, null, STORE_DELIMITER)) {
while (scanner.hasNext()) {
String line = scanner.next();
cache.put(line, line);
}
} catch (IOException e) {
throw ObjectHelper.wrapRuntimeCamelException(e);
}
LOG.debug("Loaded {} to the 1st level cache from idempotent filestore: {}", cache.size(), fileStore);
}
@Override
@SuppressWarnings("unchecked")
protected void doStart() throws Exception {
ObjectHelper.notNull(fileStore, "fileStore", this);
if (this.cache == null) {
// default use a 1st level cache
this.cache = LRUCacheFactory.newLRUCache(1000);
}
// init store if not loaded before
if (init.compareAndSet(false, true)) {
loadStore();
}
}
@Override
protected void doStop() throws Exception {
// run the cleanup task first
if (cache instanceof LRUCache) {
((LRUCache) cache).cleanUp();
}
cache.clear();
init.set(false);
}
}