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Java 1.8+ Library with tons of utility classes required in all projects
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/*
* Copyright (C) 2014-2024 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed 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 com.helger.commons.gfx;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.security.AccessControlException;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;
import javax.annotation.concurrent.ThreadSafe;
import javax.imageio.IIOException;
import javax.imageio.ImageIO;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.helger.commons.annotation.ReturnsMutableCopy;
import com.helger.commons.annotation.Singleton;
import com.helger.commons.collection.impl.CommonsHashSet;
import com.helger.commons.collection.impl.ICommonsMap;
import com.helger.commons.collection.impl.ICommonsSet;
import com.helger.commons.collection.map.LRUMap;
import com.helger.commons.concurrent.SimpleReadWriteLock;
import com.helger.commons.dimension.SizeInt;
import com.helger.commons.io.IHasInputStream;
import com.helger.commons.io.resource.IReadableResource;
import com.helger.commons.state.EChange;
import com.helger.commons.statistics.IMutableStatisticsHandlerCache;
import com.helger.commons.statistics.StatisticsManager;
/**
* This service class is used to cache information about images. It is used to
* set the HTML attributes width and height for images. It has an internal cache
* to avoid querying the data every time.
*
* @author Philip Helger
*/
@ThreadSafe
@Singleton
public final class ImageDataManager
{
private static final class SingletonHolder
{
private static final ImageDataManager INSTANCE = new ImageDataManager (1000);
}
private static final Logger LOGGER = LoggerFactory.getLogger (ImageDataManager.class);
private static final IMutableStatisticsHandlerCache STATS_COUNTER = StatisticsManager.getCacheHandler (ImageDataManager.class);
private static boolean s_bDefaultInstantiated = false;
private final SimpleReadWriteLock m_aRWLock = new SimpleReadWriteLock ();
// The main cache
@GuardedBy ("m_aRWLock")
private final ICommonsMap m_aImageData;
// A cache for all non-existing resources to avoid checking them over and over
// again
@GuardedBy ("m_aRWLock")
private final ICommonsSet m_aNonExistingResources = new CommonsHashSet <> ();
private ImageDataManager (@Nonnegative final int nMaxCacheSize)
{
m_aImageData = new LRUMap <> (nMaxCacheSize);
}
public static boolean isInstantiated ()
{
return s_bDefaultInstantiated;
}
@Nonnull
public static ImageDataManager getInstance ()
{
final ImageDataManager ret = SingletonHolder.INSTANCE;
s_bDefaultInstantiated = true;
return ret;
}
@Nullable
private static SizeInt _readImageData (@Nonnull final IHasInputStream aRes)
{
SizeInt aData = null;
// ImageIO.read doesn't close the stream!
try (final InputStream aIS = aRes.getInputStream ())
{
if (aIS != null)
{
// Returned image may be null in case it is not a valid image!
// Happens e.g. if a file with the extension ".png" is not a PNG image
final BufferedImage aImage = ImageIO.read (aIS);
if (aImage != null)
aData = new SizeInt (aImage.getWidth (), aImage.getHeight ());
else
LOGGER.warn ("Does not seem to be an image resource: " + aRes);
}
else
{
LOGGER.warn ("Failed to resolve image resource: " + aRes);
}
}
catch (final UnsatisfiedLinkError | NoClassDefFoundError ex)
{
// UnsatisfiedLinkError: Happened on Ubuntu where library libmawt.so is
// not present
// NoClassDefFoundError: Happened on Ubuntu where library libmawt.so is
// not present in a follow-up call after the
// java.lang.UnsatisfiedLinkError error occurred
LOGGER.error ("Seems like no AWT binding is present", ex);
}
catch (final IIOException ex)
{
LOGGER.error ("Failed to interprete image data from resource " + aRes + ": " + ex.getMessage ());
}
catch (final IOException ex)
{
LOGGER.error ("Failed to read image data from resource " + aRes, ex);
}
catch (final AccessControlException ex)
{
// can be thrown by f.exist!
LOGGER.error ("Whatsoever on " + aRes, ex);
}
catch (final IllegalArgumentException ex)
{
// can be thrown by the BMP reader :)
LOGGER.error ("Failed to read image data from resource " + aRes + ": " + ex.getMessage ());
}
return aData;
}
@Nullable
public SizeInt getImageSize (@Nullable final IReadableResource aRes)
{
if (aRes == null)
return null;
/*
* Use containsKey here instead of "get () != null" in case an image is
* queried over and over but is not existing. The implementation inserts
* null values for all elements that are invalid
*/
m_aRWLock.readLock ().lock ();
try
{
// Valid image data?
final SizeInt aData = m_aImageData.get (aRes);
if (aData != null)
{
STATS_COUNTER.cacheHit ();
return aData;
}
// Known non-existing image data?
if (m_aNonExistingResources.contains (aRes))
{
STATS_COUNTER.cacheHit ();
return null;
}
}
finally
{
m_aRWLock.readLock ().unlock ();
}
// Main read data outside of lock!
final SizeInt aData = _readImageData (aRes);
m_aRWLock.writeLocked ( () -> {
// In case the image is invalid (why-so-ever), remember a null value
if (aData == null)
m_aNonExistingResources.add (aRes);
else
m_aImageData.put (aRes, aData);
STATS_COUNTER.cacheMiss ();
});
return aData;
}
/**
* Remove a single resource from the cache.
*
* @param aRes
* The resource to be removed. May be null.
* @return Never null.
*/
@Nonnull
public EChange clearCachedSize (@Nullable final IReadableResource aRes)
{
if (aRes == null)
return EChange.UNCHANGED;
return m_aRWLock.writeLockedGet ( () -> {
// Existing resource?
if (m_aImageData.remove (aRes) != null)
return EChange.CHANGED;
// Non-existing resource?
if (m_aNonExistingResources.remove (aRes))
return EChange.CHANGED;
return EChange.UNCHANGED;
});
}
/**
* Remove all cached elements
*
* @return {@link EChange} - never null
*/
@Nonnull
public EChange clearCache ()
{
return m_aRWLock.writeLockedGet ( () -> {
if (m_aImageData.isEmpty () && m_aNonExistingResources.isEmpty ())
return EChange.UNCHANGED;
m_aImageData.clear ();
m_aNonExistingResources.clear ();
if (LOGGER.isDebugEnabled ())
LOGGER.debug ("Cache was cleared: " + ImageDataManager.class.getName ());
return EChange.CHANGED;
});
}
@Nonnull
@ReturnsMutableCopy
public ICommonsMap getAllCachedSizes ()
{
return m_aRWLock.readLockedGet (m_aImageData::getClone);
}
@Nonnull
@ReturnsMutableCopy
public ICommonsSet getAllNotExistingResources ()
{
return m_aRWLock.readLockedGet (m_aNonExistingResources::getClone);
}
}