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package com.sun.enterprise.web.connector.grizzly;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.tomcat.util.http.MimeHeaders;
/**
* This class implements a file caching mechanism used to cache static resources.
*
* @author Jeanfrancois Arcand
* @author Scott Oaks
*/
public class FileCache{
public final static String DEFAULT_SERVLET_NAME = "default";
/**
* A <code>ByteBuffer</code> cache of static pages.
*/
private final ConcurrentHashMap<String,FileCacheEntry> fileCache =
new ConcurrentHashMap<String,FileCacheEntry>();
/**
* A dummy instance of <code>ByteBuffer</code>
*/
private final static ByteBuffer nullByteBuffer =
(ByteBuffer) ByteBuffer.allocate(0);
/**
* A connection: close of <code>ByteBuffer</code>
*/
protected final static ByteBuffer connectionCloseBB =
ByteBuffer.wrap("Connection: close\r\n\r\n".getBytes());
/**
* A connection: keep-alive of <code>ByteBuffer</code>
*/
protected final static ByteBuffer connectionKaBB =
ByteBuffer.wrap("Connection: keep-alive\r\n\r\n".getBytes());
/**
* HTTP end line.
*/
private final static String NEWLINE = "\r\n";
/**
* HTTP OK header
*/
public final static String OK = "HTTP/1.1 200 OK" + NEWLINE;
/**
* The port associated with this cache.
*/
private int port = 8080;
/**
* Scheduled Thread that clean the cache every XX seconds.
*/
private ScheduledThreadPoolExecutor cacheResourcesThread
= new ScheduledThreadPoolExecutor(1,
new GrizzlyThreadFactory("FileCacheThread-" + port,
1,Thread.NORM_PRIORITY));
/**
* FileCacheEntry cache
*/
private ConcurrentLinkedQueue<FileCacheEntry> cacheManager;
/**
* Timeout before remove the static resource from the cache.
*/
private int secondsMaxAge = -1;
/**
* The maximum entries in the <code>fileCache</code>
*/
private int maxCacheEntries = 1024;
/**
* The maximum size of a cached resources.
*/
private long minEntrySize = 2048;
/**
* The maximum size of a cached resources.
*/
private long maxEntrySize = 537600;
/**
* The maximum memory mapped bytes
*/
private long maxLargeFileCacheSize = 10485760;
/**
* The maximum cached bytes
*/
private long maxSmallFileCacheSize = 1048576;
/**
* The current cache size in bytes
*/
private static long mappedMemorySize = 0;
/**
* The current cache size in bytes
*/
private static long heapSize = 0;
/**
* Is the file cache enabled.
*/
private boolean isEnabled = true;
/**
* Is the large FileCache enabled.
*/
private boolean isLargeFileCacheEnabled = true;
/**
* Is monitoring enabled.
*/
private static boolean isMonitoringEnabled = false;
/**
* The number of current open cache entries
*/
private int openCacheEntries = 0;
/**
* The number of max current open cache entries
*/
private int maxOpenCacheEntries = 0;
/**
* Max heap space used for cache
*/
private long maxHeapCacheSize = 0;
/**
* Max mapped memory used for cache
*/
private long maxMappedMemory = 0;
/**
* Number of cache lookup hits
*/
private int countHits = 0;
/**
* Number of cache lookup misses
*/
private int countMisses = 0;
/**
* Number of hits on cached file info
*/
private int countCacheHits;
/**
* Number of misses on cached file info
*/
private int countCacheMisses;
/**
* Number of hits on cached file info
*/
private int countMappedHits;
/**
* Number of misses on cached file info
*/
private int countMappedMisses;
/**
* The Header ByteBuffer default size.
*/
private int headerBBSize = 4096;
// ---------------------------------------------------- Methods ----------//
/**
* Add a resource to the cache. Currently, only static resources served
* by the DefaultServlet can be cached.
*/
public synchronized void add(String mappedServlet, String baseDir,
String requestURI, MimeHeaders headers, boolean xPoweredBy){
if ( fileCache.get(requestURI) != null) return;
// cache is full.
if ( fileCache.size() > maxCacheEntries) {
return;
}
if ( mappedServlet.equals(DEFAULT_SERVLET_NAME) ){
File file = new File(baseDir + requestURI);
ByteBuffer bb = mapFile(file);
// Always put the answer into the map. If it's null, then
// we know that it doesn't fit into the cache, so there's no
// reason to go through this code again.
if (bb == null)
bb = nullByteBuffer;
FileCacheEntry entry = cacheManager.poll();
if ( entry == null){
entry = new FileCacheEntry();
}
entry.bb = bb;
entry.requestURI = requestURI;
if ( bb != nullByteBuffer){
entry.lastModified = headers.getHeader("Last-Modified");
entry.contentType = headers.getHeader("content-type");
entry.xPoweredBy = xPoweredBy;
entry.isInHeap = (file.length() < minEntrySize);
entry.date = headers.getHeader("Date");
entry.Etag = headers.getHeader("Etag");
configHeaders(entry);
if ( isMonitoringEnabled ) {
openCacheEntries++;
if ( openCacheEntries > maxOpenCacheEntries){
maxOpenCacheEntries = openCacheEntries;
}
if ( heapSize > maxHeapCacheSize){
maxHeapCacheSize = heapSize;
}
if ( mappedMemorySize > maxMappedMemory){
maxMappedMemory = mappedMemorySize;
}
}
if ( secondsMaxAge > 0 ) {
entry.future = cacheResourcesThread.schedule(entry,
secondsMaxAge, TimeUnit.SECONDS);
}
}
fileCache.put(requestURI,entry);
}
}
/**
* Map the file to a <code>ByteBuffer</code>
* @return the <code>ByteBuffer</code>
*/
private final ByteBuffer mapFile(File file){
FileChannel fileChannel = null;
FileInputStream stream = null;
try {
stream = new FileInputStream(file);
fileChannel = stream.getChannel();
long size = fileChannel.size();
if ( !isLargeFileCacheEnabled ) {
// Large file support are not enabled
if ( size > minEntrySize ) {
return null;
}
} else if ( size > maxEntrySize){
return null;
}
if ( size > minEntrySize )
mappedMemorySize+= size;
else
heapSize+= size;
// Cache full
if ( mappedMemorySize > maxLargeFileCacheSize ) {
mappedMemorySize-= size;
return null;
} else if ( heapSize > maxSmallFileCacheSize ) {
heapSize-= size;
return null;
}
ByteBuffer bb =
fileChannel.map(FileChannel.MapMode.READ_ONLY,0,size);
if ( size < minEntrySize) {
((MappedByteBuffer)bb).load();
}
return bb;
} catch (IOException ioe) {
return null;
} finally {
if (stream != null) {
try {
stream.close();
} catch (IOException ioe) {
}
}
if (fileChannel != null) {
try {
fileChannel.close();
} catch (IOException ioe) {
}
}
}
}
/**
* Return <code>true</code> if the file is cached.
*/
private final FileCacheEntry map(byte[] requestBytes,int start, int length){
String uri = "";
FileCacheEntry entry = null;
if ( !fileCache.isEmpty() ){
uri = new String(requestBytes,start,length);
entry = fileCache.get(uri);
if ( isMonitoringEnabled) {
if (entry != null && entry.bb != null
&& entry.bb != nullByteBuffer){
if ( entry.isInHeap )
countCacheHits++;
else
countMappedHits++;
countHits++;
} else {
countMisses++;
}
}
}
return entry;
}
/**
* Send the cache.
*/
public boolean sendCache(byte[] req, int start, int length,
SocketChannel socketChannel, boolean keepAlive){
try{
FileCacheEntry entry = map(req,start,length);
if ( entry != null && entry.bb != nullByteBuffer){
sendCache(socketChannel,entry,keepAlive);
return true;
}
} catch (IOException ex){
SelectorThread.logger()
.fine("File Cache: " + ex.getMessage());
return true;
} catch (Throwable t){
// If an unexpected exception occurs, try to serve the page
// as if it wasn't in a cache.
SelectorThread.logger()
.fine("File Cache thread race: " + t.getMessage());
}
return false;
}
/**
* Set the cache manager used by this instance.
*/
public void setCacheManager(ConcurrentLinkedQueue cacheManager){
this.cacheManager = cacheManager;
}
// -------------------------------------------------- Static cache -------/
/**
* Send the cached resource.
*/
protected void sendCache(SocketChannel socketChannel, FileCacheEntry entry,
boolean keepAlive) throws IOException{
OutputWriter.flushChannel(socketChannel, entry.headerBuffer.slice());
ByteBuffer keepAliveBuf = keepAlive ? connectionKaBB.slice():
connectionCloseBB.slice();
OutputWriter.flushChannel(socketChannel, keepAliveBuf);
OutputWriter.flushChannel(socketChannel, entry.bb.slice());
}
/**
* Return a <code>ByteBuffer</code> contains the server header.
*/
private void configHeaders(FileCacheEntry entry) {
if ( entry.headerBuffer == null ) {
entry.headerBuffer =
ByteBuffer.allocate(getHeaderBBSize());
}
StringBuffer sb = new StringBuffer();
sb.append(OK);
if ( entry.xPoweredBy){
appendHeaderValue(sb,"X-Powered-By", "Servlet/2.5");
}
appendHeaderValue(sb, "ETag", entry.Etag);
appendHeaderValue(sb,"Last-Modified", entry.lastModified);
appendHeaderValue(sb,"Content-Type", entry.contentType);
appendHeaderValue(sb,"Content-Length", entry.bb.capacity() + "");
appendHeaderValue(sb,"Date", entry.date);
appendHeaderValue(sb,"Server", SelectorThread.SERVER_NAME);
entry.headerBuffer.put(sb.toString().getBytes());
entry.headerBuffer.flip();
}
/**
* Utility to add headers to the HTTP response.
*/
private void appendHeaderValue(StringBuffer sb,String name, String value) {
sb.append(name);
sb.append(": ");
sb.append(value);
sb.append(NEWLINE);
}
public final class FileCacheEntry implements Runnable{
public String requestURI;
public String lastModified;
public String contentType;
public ByteBuffer bb;
public ByteBuffer headerBuffer;
public boolean xPoweredBy;
public boolean isInHeap = false;
public String date;
public String Etag;
public Future future;
public void run(){
fileCache.remove(requestURI);
if (requestURI == null) return;
if (headerBuffer != null) {
/**
* If the position !=0, it means the ByteBuffer has a view
* that is still used. If that's the case, wait another 10 seconds
* before marking the ByteBuffer for garbage collection
*/
if ( headerBuffer.position() !=0 || bb.position() != 0 ){
future = cacheResourcesThread
.schedule(this, 10, TimeUnit.SECONDS);
return;
}
if ( !isInHeap )
mappedMemorySize -= bb.limit();
else
heapSize -= bb.limit();
bb = null;
headerBuffer = null;
openCacheEntries--;
}
if ( future != null ) {
future.cancel(false);
future = null;
}
requestURI = null;
cacheManager.offer(this);
}
}
// ---------------------------------------------------- Monitoring --------//
/**
* Returns flag indicating whether file cache has been enabled
* @return 1 if file cache has been enabled, 0 otherwise
*/
public int getFlagEnabled() {
return (isEnabled == true?1:0);
}
/**
* Return the maximum age of a valid cache entry
* @return cache entry maximum age
*/
public int getSecondsMaxAge() {
return secondsMaxAge;
}
/**
* Return the number of current cache entries.
* @return current cache entries
*/
public long getCountEntries() {
return fileCache.size();
}
/**
* Return the maximum number of cache entries
* @return maximum cache entries
*/
public long getMaxEntries() {
return maxCacheEntries;
}
/**
* The number of current open cache entries
* @return open cache entries
*/
public long getCountOpenEntries() {
return openCacheEntries;
}
/**
* Return the maximum number of open cache entries
* @return maximum open cache entries
*/
public long getMaxOpenEntries() {
return maxOpenCacheEntries;
}
/**
* Return the heap space used for cache
* @return heap size
*/
public long getSizeHeapCache() {
return heapSize;
}
/**
* Return the maximum heap space used for cache
* @return maximum heap size
*/
public long getMaxHeapCacheSize() {
return maxHeapCacheSize;
}
/**
* Return the size of Mapped memory used for caching
* @return Mapped memory size
*/
public static long getSizeMmapCache() {
return mappedMemorySize;
}
/**
* Return the Maximum Memory Map size to be used for caching
* @return maximum Memory Map size
*/
public long getMaxMmapCacheSize() {
return maxMappedMemory;
}
/**
* Return the Number of cache lookup hits
* @return cache hits
*/
public long getCountHits() {
return countHits;
}
/**
* Return the Number of cache lookup misses
* @return cache misses
*/
public long getCountMisses() {
return countMisses;
}
/**
* The Number of hits on cached file info
* @return hits on cached file info
*/
public long getCountInfoHits() {
return countCacheHits;
}
/**
* Return the number of misses on cached file info
* @return misses on cache file info
*/
public long getCountInfoMisses() {
return countCacheMisses;
}
/**
* Return the Number of hits on cached file content
* @return hits on cache file content
*/
public long getCountContentHits() {
return countMappedHits;
}
/**
* Return the Number of misses on cached file content
* @return missed on cached file content
*/
public int getCountContentMisses() {
return countMappedMisses;
}
// ---------------------------------------------------- Properties ----- //
/**
* Turn monitoring on/off
*/
public static void setIsMonitoringEnabled(boolean isMe){
isMonitoringEnabled = isMe;
}
/**
* The timeout in seconds before remove a <code>FileCacheEntry</code>
* from the <code>fileCache</code>
*/
public void setSecondsMaxAge(int sMaxAges){
secondsMaxAge = sMaxAges;
}
/**
* Set the maximum entries this cache can contains.
*/
public void setMaxCacheEntries(int mEntries){
maxCacheEntries = mEntries;
}
/**
* Return the maximum entries this cache can contains.
*/
public int getMaxCacheEntries(){
return maxCacheEntries;
}
/**
* Set the maximum size a <code>FileCacheEntry</code> can have.
*/
public void setMinEntrySize(long mSize){
minEntrySize = mSize;
}
/**
* Get the maximum size a <code>FileCacheEntry</code> can have.
*/
public long getMinEntrySize(){
return minEntrySize;
}
/**
* Set the maximum size a <code>FileCacheEntry</code> can have.
*/
public void setMaxEntrySize(long mEntrySize){
maxEntrySize = mEntrySize;
}
/**
* Get the maximum size a <code>FileCacheEntry</code> can have.
*/
public long getMaxEntrySize(){
return maxEntrySize;
}
/**
* Set the maximum cache size
*/
public void setMaxLargeCacheSize(long mCacheSize){
maxLargeFileCacheSize = mCacheSize;
}
/**
* Get the maximum cache size
*/
public long getMaxLargeCacheSize(){
return maxLargeFileCacheSize;
}
/**
* Set the maximum cache size
*/
public void setMaxSmallCacheSize(long mCacheSize){
maxSmallFileCacheSize = mCacheSize;
}
/**
* Get the maximum cache size
*/
public long getMaxSmallCacheSize(){
return maxSmallFileCacheSize;
}
/**
* Is the fileCache enabled.
*/
public boolean isEnabled(){
return isEnabled;
}
/**
* Is the file caching mechanism enabled.
*/
public void setIsEnabled(boolean isEnabled){
this.isEnabled = isEnabled;
}
/**
* Is the large file cache support enabled.
*/
public void setLargeFileCacheEnabled(boolean isLargeEnabled){
this.isLargeFileCacheEnabled = isLargeEnabled;
}
/**
* Is the large file cache support enabled.
*/
public boolean getLargeFileCacheEnabled(){
return isLargeFileCacheEnabled;
}
/**
* Return the FileCache
*/
public ConcurrentHashMap getCache(){
return fileCache;
}
/**
* Retunr the header size buffer.
*/
public int getHeaderBBSize() {
return headerBBSize;
}
/**
* Set the size of the header ByteBuffer.
*/
public void setHeaderBBSize(int headerBBSize) {
this.headerBBSize = headerBBSize;
}
}
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