I want to implement a custom FaceletCacheFactory providing a custom FaceletCache.
The reason I want to do it is to try out a fix for issue '[JAVASERVERFACES-4107] Facelet cache doesn't expire / refresh Facelets correctly' in the DefaultFaceletCache that is available in Mojarra javax.faces-2.3.0-m06, but not in Mojarra javax.faces-2.2.8-17.
I want to try the fix in the hope it addresses this strange recent problem I have encountered: Mac: JSF: why are development stage JSF web apps not always catching composite component changes?
My naive first attempt was to simply try to create a CustomFaceletFactory that provides a CustomFaceletCacheJSF3 reproducing the DefaultFaceletCache from Mojarra javax.faces-2.3.0-m06 as shown below, but it fails because com.sun.faces.facelets.impl.DefaultFacelet is not public and can't be imported:
public class CustomFaceletCacheJSF3 extends FaceletCache<DefaultFacelet> {
private final static Logger LOGGER = FacesLogger.FACELETS_FACTORY.getLogger();
/**
*Constructor
* @param refreshPeriod cache refresh period (in seconds).
* 0 means 'always refresh', negative value means 'never refresh'
*/
CustomFaceletCacheJSF3(final long refreshPeriod) {
// We will be delegating object storage to the ExpiringCocurrentCache
// Create Factory objects here for the cache. The objects will be delegating to our
// own instance factories
final boolean checkExpiry = (refreshPeriod > 0);
ConcurrentCache.Factory<URL, Record> faceletFactory =
new ConcurrentCache.Factory<URL, Record>() {
@Override
public Record newInstance(final URL key) throws IOException {
// Make sure that the expensive timestamp retrieval is not done
// if no expiry check is going to be performed
long lastModified = checkExpiry ? Util.getLastModified(key) : 0;
return new Record(System.currentTimeMillis(), lastModified,
getMemberFactory().newInstance(key), refreshPeriod);
}
};
ConcurrentCache.Factory<URL, Record> metadataFaceletFactory =
new ConcurrentCache.Factory<URL, Record>() {
@Override
public Record newInstance(final URL key) throws IOException {
// Make sure that the expensive timestamp retrieval is not done
// if no expiry check is going to be performed
long lastModified = checkExpiry ? Util.getLastModified(key) : 0;
return new Record(System.currentTimeMillis(), lastModified,
getMetadataMemberFactory().newInstance(key), refreshPeriod);
}
};
// No caching if refreshPeriod is 0
if (refreshPeriod == 0) {
_faceletCache = new NoCache(faceletFactory);
_metadataFaceletCache = new NoCache(metadataFaceletFactory);
} else {
ExpiringConcurrentCache.ExpiryChecker<URL, Record> checker =
(refreshPeriod > 0) ? new ExpiryChecker() : new NeverExpired();
_faceletCache =
new ExpiringConcurrentCache<>(faceletFactory,
checker);
_metadataFaceletCache =
new ExpiringConcurrentCache<>(metadataFaceletFactory,
checker);
}
}
@Override
public DefaultFacelet getFacelet(URL url) throws IOException {
com.sun.faces.util.Util.notNull("url", url);
DefaultFacelet f = null;
try {
f = _faceletCache.get(url).getFacelet();
} catch (ExecutionException e) {
_unwrapIOException(e);
}
return f;
}
@Override
public boolean isFaceletCached(URL url) {
com.sun.faces.util.Util.notNull("url", url);
return _faceletCache.containsKey(url);
}
@Override
public DefaultFacelet getViewMetadataFacelet(URL url) throws IOException {
com.sun.faces.util.Util.notNull("url", url);
DefaultFacelet f = null;
try {
f = _metadataFaceletCache.get(url).getFacelet();
} catch (ExecutionException e) {
_unwrapIOException(e);
}
return f;
}
@Override
public boolean isViewMetadataFaceletCached(URL url) {
com.sun.faces.util.Util.notNull("url", url);
return _metadataFaceletCache.containsKey(url);
}
private void _unwrapIOException(ExecutionException e) throws IOException {
Throwable t = e.getCause();
if (t instanceof IOException) {
throw (IOException)t;
}
if (t.getCause() instanceof IOException) {
throw (IOException)t.getCause();
}
if (t instanceof RuntimeException) {
throw (RuntimeException)t;
}
throw new FacesException(t);
}
private final ConcurrentCache<URL, Record> _faceletCache;
private final ConcurrentCache<URL, Record> _metadataFaceletCache;
/**
* This class holds the Facelet instance and its original URL's last modified time. It also produces
* the time when the next expiry check should be performed
*/
private static class Record {
Record(long creationTime, long lastModified, DefaultFacelet facelet, long refreshInterval) {
_facelet = facelet;
_creationTime = creationTime;
_lastModified = lastModified;
_refreshInterval = refreshInterval;
// There is no point in calculating the next refresh time if we are refreshing always/never
_nextRefreshTime = (_refreshInterval > 0) ? new AtomicLong(creationTime + refreshInterval) : null;
}
DefaultFacelet getFacelet() {
return _facelet;
}
long getLastModified() {
return _lastModified;
}
long getNextRefreshTime() {
// There is no point in calculating the next refresh time if we are refreshing always/never
return (_refreshInterval > 0) ? _nextRefreshTime.get() : 0;
}
long getAndUpdateNextRefreshTime() {
// There is no point in calculating the next refresh time if we are refreshing always/never
return (_refreshInterval > 0) ? _nextRefreshTime.getAndAdd(_refreshInterval) : 0;
}
private final long _lastModified;
private final long _refreshInterval;
private final long _creationTime;
private final AtomicLong _nextRefreshTime;
private final DefaultFacelet _facelet;
}
private static class ExpiryChecker implements ExpiringConcurrentCache.ExpiryChecker<URL, Record> {
@Override
public boolean isExpired(URL url, Record record) {
if (System.currentTimeMillis() > record.getNextRefreshTime()) {
record.getAndUpdateNextRefreshTime();
long lastModified = Util.getLastModified(url);
// The record is considered expired if its original last modified time
// is older than the URL's current last modified time
return (lastModified > record.getLastModified());
}
return false;
}
}
private static class NeverExpired implements ExpiringConcurrentCache.ExpiryChecker<URL, Record> {
@Override
public boolean isExpired(URL key, Record value) {
return false;
}
}
/**
* ConcurrentCache implementation that does no caching (always creates new instances)
*/
private static class NoCache extends ConcurrentCache<URL, Record> {
public NoCache(ConcurrentCache.Factory<URL, Record> f) {
super(f);
}
@Override
public Record get(final URL key) throws ExecutionException {
try {
return this.getFactory().newInstance(key);
} catch (Exception e) {
throw new ExecutionException(e);
}
}
@Override
public boolean containsKey(final URL key) {
return false;
}
}
}
