org.apache.wiki.providers.CachingProvider Maven / Gradle / Ivy
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to you under the Apache License, Version 2.0 (the
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package org.apache.wiki.providers;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.wiki.api.core.Context;
import org.apache.wiki.api.core.Engine;
import org.apache.wiki.api.core.Page;
import org.apache.wiki.api.exceptions.NoRequiredPropertyException;
import org.apache.wiki.api.exceptions.ProviderException;
import org.apache.wiki.api.providers.PageProvider;
import org.apache.wiki.api.search.QueryItem;
import org.apache.wiki.api.search.SearchResult;
import org.apache.wiki.api.spi.Wiki;
import org.apache.wiki.cache.CacheInfo;
import org.apache.wiki.cache.CachingManager;
import org.apache.wiki.pages.PageManager;
import org.apache.wiki.parser.MarkupParser;
import org.apache.wiki.render.RenderingManager;
import org.apache.wiki.util.ClassUtil;
import org.apache.wiki.util.TextUtil;
import java.io.IOException;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Properties;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicLong;
/**
* Provides a caching page provider. This class rests on top of a real provider class and provides a cache to speed things up. Only
* if the cache copy of the page text has expired, we fetch it from the provider.
*
* This class does not detect if someone has modified the page externally, not through JSPWiki routines.
*
* Heavily based on ideas by Chris Brooking.
*
* Since 2.10 uses the Ehcache library.
*
* @since 1.6.4
*/
public class CachingProvider implements PageProvider {
private static final Logger LOG = LogManager.getLogger( CachingProvider.class );
private CachingManager cachingManager;
private PageProvider provider;
private Engine engine;
private boolean allRequested;
private final AtomicLong pages = new AtomicLong( 0L );
/**
* {@inheritDoc}
*/
@Override
public void initialize( final Engine engine, final Properties properties ) throws NoRequiredPropertyException, IOException {
LOG.debug( "Initing CachingProvider" );
// engine is used for getting the search engine
this.engine = engine;
cachingManager = this.engine.getManager( CachingManager.class );
// Find and initialize real provider.
final String classname;
try {
classname = TextUtil.getRequiredProperty( properties, PageManager.PROP_PAGEPROVIDER );
} catch( final NoSuchElementException e ) {
throw new NoRequiredPropertyException( e.getMessage(), PageManager.PROP_PAGEPROVIDER );
}
try {
provider = ClassUtil.buildInstance( "org.apache.wiki.providers", classname );
LOG.debug( "Initializing real provider class {}", provider );
provider.initialize( engine, properties );
} catch( final ReflectiveOperationException e ) {
LOG.error( "Unable to instantiate provider class {}", classname, e );
throw new IllegalArgumentException( "illegal provider class", e );
}
}
private Page getPageInfoFromCache( final String name ) throws ProviderException {
// Sanity check; seems to occur sometimes
if( name == null ) {
return null;
}
return cachingManager.get( CachingManager.CACHE_PAGES, name, () -> provider.getPageInfo( name, PageProvider.LATEST_VERSION ) );
}
/**
* {@inheritDoc}
*/
@Override
public boolean pageExists( final String pageName, final int version ) {
if( pageName == null ) {
return false;
}
final Page p;
try {
p = getPageInfoFromCache( pageName );
} catch( final ProviderException e ) {
LOG.info( "Provider failed while trying to check if page exists: {}", pageName );
return false;
}
if( p != null ) {
final int latestVersion = p.getVersion();
if( version == latestVersion || version == LATEST_VERSION ) {
return true;
}
return provider.pageExists( pageName, version );
}
try {
return getPageInfo( pageName, version ) != null;
} catch( final ProviderException e ) {
LOG.info( "Provider failed while retrieving {}", pageName );
}
return false;
}
/**
* {@inheritDoc}
*/
@Override
public boolean pageExists( final String pageName ) {
if( pageName == null ) {
return false;
}
final Page p;
try {
p = getPageInfoFromCache( pageName );
} catch( final ProviderException e ) {
LOG.info( "Provider failed while trying to check if page exists: {}", pageName );
return false;
}
// A null item means that the page either does not exist, or has not yet been cached; a non-null means that the page does exist.
if( p != null ) {
return true;
}
// If we have a list of all pages in memory, then any page not in the cache must be non-existent.
if( pages.get() < cachingManager.info( CachingManager.CACHE_PAGES ).getMaxElementsAllowed() ) {
return false;
}
// We could add the page to the cache here as well, but in order to understand whether that is a good thing or not we would
// need to analyze the JSPWiki calling patterns extensively. Presumably it would be a good thing if pageExists() is called
// many times before the first getPageText() is called, and the whole page is cached.
return provider.pageExists( pageName );
}
/**
* {@inheritDoc}
*/
@Override
public String getPageText( final String pageName, final int version ) throws ProviderException {
if( pageName == null ) {
return null;
}
final String result;
if( version == PageProvider.LATEST_VERSION ) {
result = getTextFromCache( pageName );
} else {
final Page p = getPageInfoFromCache( pageName );
// Or is this the latest version fetched by version number?
if( p != null && p.getVersion() == version ) {
result = getTextFromCache( pageName );
} else {
result = provider.getPageText( pageName, version );
}
}
return result;
}
private String getTextFromCache( final String pageName ) throws ProviderException {
if( pageName == null ) {
return null;
}
return cachingManager.get( CachingManager.CACHE_PAGES_TEXT, pageName, () -> {
if( pageExists( pageName ) ) {
return provider.getPageText( pageName, PageProvider.LATEST_VERSION );
}
return null;
} );
}
/**
* {@inheritDoc}
*/
@Override
public void putPageText( final Page page, final String text ) throws ProviderException {
synchronized( this ) {
provider.putPageText( page, text );
page.setLastModified( new Date() );
// Refresh caches properly
cachingManager.remove( CachingManager.CACHE_PAGES, page.getName() );
cachingManager.remove( CachingManager.CACHE_PAGES_TEXT, page.getName() );
cachingManager.remove( CachingManager.CACHE_PAGES_HISTORY, page.getName() );
getPageInfoFromCache( page.getName() );
}
pages.incrementAndGet();
}
/**
* {@inheritDoc}
*/
@Override
public Collection< Page > getAllPages() throws ProviderException {
final Collection< Page > all;
if ( !allRequested ) {
all = provider.getAllPages();
// Make sure that all pages are in the cache.
synchronized( this ) {
for( final Page p : all ) {
cachingManager.put( CachingManager.CACHE_PAGES, p.getName(), p );
}
allRequested = true;
}
pages.set( all.size() );
} else {
final List< String > keys = cachingManager.keys( CachingManager.CACHE_PAGES );
all = new TreeSet<>();
for( final String key : keys ) {
final Page cachedPage = cachingManager.get( CachingManager.CACHE_PAGES, key, () -> null );
if( cachedPage != null ) {
all.add( cachedPage );
}
}
}
if( cachingManager.enabled( CachingManager.CACHE_PAGES )
&& pages.get() >= cachingManager.info( CachingManager.CACHE_PAGES ).getMaxElementsAllowed() ) {
LOG.warn( "seems {} can't hold all pages from your page repository, " +
"so we're delegating on the underlying provider instead. Please consider increasing " +
"your cache sizes on the ehcache configuration file to avoid this behaviour", CachingManager.CACHE_PAGES );
return provider.getAllPages();
}
return all;
}
/**
* {@inheritDoc}
*/
@Override
public Collection< Page > getAllChangedSince( final Date date ) {
return provider.getAllChangedSince( date );
}
/**
* {@inheritDoc}
*/
@Override
public int getPageCount() throws ProviderException {
return provider.getPageCount();
}
/**
* {@inheritDoc}
*/
@Override
public Collection< SearchResult > findPages( final QueryItem[] query ) {
// If the provider is a fast searcher, then just pass this request through.
return provider.findPages( query );
// FIXME: Does not implement fast searching
}
// FIXME: Kludge: make sure that the page is also parsed and it gets all the necessary variables.
private void refreshMetadata( final Page page ) {
if( page != null && !page.hasMetadata() ) {
final RenderingManager mgr = engine.getManager( RenderingManager.class );
try {
final String data = provider.getPageText( page.getName(), page.getVersion() );
final Context ctx = Wiki.context().create( engine, page );
final MarkupParser parser = mgr.getParser( ctx, data );
parser.parse();
} catch( final Exception ex ) {
LOG.debug( "Failed to retrieve variables for wikipage {}", page );
}
}
}
/**
* {@inheritDoc}
*/
@Override
public Page getPageInfo( final String pageName, final int version ) throws ProviderException {
final Page page;
final Page cached = getPageInfoFromCache( pageName );
final int latestcached = ( cached != null ) ? cached.getVersion() : Integer.MIN_VALUE;
if( version == PageProvider.LATEST_VERSION || version == latestcached ) {
page = cached;
} else {
// We do not cache old versions.
page = provider.getPageInfo( pageName, version );
}
refreshMetadata( page );
return page;
}
/**
* {@inheritDoc}
*/
@Override
public List< Page > getVersionHistory( final String pageName) throws ProviderException {
if( pageName == null ) {
return null;
}
return cachingManager.get( CachingManager.CACHE_PAGES_HISTORY, pageName, () -> provider.getVersionHistory( pageName ) );
}
/**
* Gets the provider class name, and cache statistics (misscount and hitcount of page cache and history cache).
*
* @return A plain string with all the above-mentioned values.
*/
@Override
public synchronized String getProviderInfo() {
final CacheInfo pageCacheInfo = cachingManager.info( CachingManager.CACHE_PAGES );
final CacheInfo pageHistoryCacheInfo = cachingManager.info( CachingManager.CACHE_PAGES_HISTORY );
return "Real provider: " + provider.getClass().getName()+
". Page cache hits: " + pageCacheInfo.getHits() +
". Page cache misses: " + pageCacheInfo.getMisses() +
". History cache hits: " + pageHistoryCacheInfo.getHits() +
". History cache misses: " + pageHistoryCacheInfo.getMisses();
}
/**
* {@inheritDoc}
*/
@Override
public void deleteVersion( final String pageName, final int version ) throws ProviderException {
// Luckily, this is such a rare operation it is okay to synchronize against the whole thing.
synchronized( this ) {
final Page cached = getPageInfoFromCache( pageName );
final int latestcached = ( cached != null ) ? cached.getVersion() : Integer.MIN_VALUE;
// If we have this version cached, remove from cache.
if( version == PageProvider.LATEST_VERSION || version == latestcached ) {
cachingManager.remove( CachingManager.CACHE_PAGES, pageName );
cachingManager.remove( CachingManager.CACHE_PAGES_TEXT, pageName );
}
provider.deleteVersion( pageName, version );
cachingManager.remove( CachingManager.CACHE_PAGES_HISTORY, pageName );
}
if( version == PageProvider.LATEST_VERSION ) {
pages.decrementAndGet();
}
}
/**
* {@inheritDoc}
*/
@Override
public void deletePage( final String pageName ) throws ProviderException {
// See note in deleteVersion().
synchronized( this ) {
cachingManager.put( CachingManager.CACHE_PAGES, pageName, null );
cachingManager.put( CachingManager.CACHE_PAGES_TEXT, pageName, null );
cachingManager.put( CachingManager.CACHE_PAGES_HISTORY, pageName, null );
provider.deletePage( pageName );
}
pages.decrementAndGet();
}
/**
* {@inheritDoc}
*/
@Override
public void movePage( final String from, final String to ) throws ProviderException {
provider.movePage( from, to );
synchronized( this ) {
// Clear any cached version of the old page and new page
cachingManager.remove( CachingManager.CACHE_PAGES, from );
cachingManager.remove( CachingManager.CACHE_PAGES_TEXT, from );
cachingManager.remove( CachingManager.CACHE_PAGES_HISTORY, from );
LOG.debug( "Removing to page {} from cache", to );
cachingManager.remove( CachingManager.CACHE_PAGES, to );
cachingManager.remove( CachingManager.CACHE_PAGES_TEXT, to );
cachingManager.remove( CachingManager.CACHE_PAGES_HISTORY, to );
}
}
/**
* Returns the actual used provider.
*
* @since 2.0
* @return The real provider.
*/
public PageProvider getRealProvider() {
return provider;
}
}