/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.filter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.ReportElement;
import org.pentaho.reporting.engine.classic.core.function.ExpressionRuntime;
import org.pentaho.reporting.libraries.resourceloader.Resource;
import org.pentaho.reporting.libraries.resourceloader.ResourceException;
import org.pentaho.reporting.libraries.resourceloader.ResourceManager;
import org.pentaho.reporting.libraries.resourceloader.factory.drawable.DrawableWrapper;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.URL;
import java.sql.Blob;
import java.util.HashSet;
/**
* The DrawableLoadFilter is used to load drawable image files (like WMF's) during the report generation process. This
* filter expects its datasource to return a java.net.URL. If the datasource does not return an URL, <code>null</code>
* is returned as result of calling "getValue()".
* <p/>
* This filter is mostly used in conjunction with the URLFilter, which creates URLs from Strings and files if nessesary.
* <p/>
* The url is used to create a new Drawable object which is returned to the caller. The loaded/created Drawable is also
* stored in an internal cache.
* <p/>
* This filter can be used to dynamically change images of a report, a very nice feature for photo albums and catalogs
* for instance.
* <p/>
* This filter will return null, if something else than an URL was retrieved from the assigned datasource
*
* @author Thomas Morgner
*/
public class DrawableLoadFilter implements DataFilter {
private static final Log logger = LogFactory.getLog( DrawableLoadFilter.class );
/**
* The cache for failed images. This prevents unneccessary retries on known-to-be-buggy URLs.
*/
private transient HashSet<String> failureCache;
/**
* The datasource from where to read the urls.
*/
private DataSource source;
/**
* creates a new ImageLoadFilter with a cache size of 10.
*/
public DrawableLoadFilter() {
this( 10 );
}
/**
* Creates a new ImageLoadFilter with the defined cache size.
*
* @param cacheSize
* the cache size.
*/
public DrawableLoadFilter( final int cacheSize ) {
failureCache = new HashSet<String>( cacheSize );
}
/**
* Reads this filter's datasource and if the source returned an URL, tries to form a imagereference. If the image is
* loaded in a previous run and is still in the cache, no new reference is created and the previously loaded reference
* is returned.
*
* @param runtime
* the expression runtime that is used to evaluate formulas and expressions when computing the value of this
* filter.
* @param element
* @return the current value for this filter.
*/
public Object getValue( final ExpressionRuntime runtime, final ReportElement element ) {
final DataSource ds = getDataSource();
if ( ds == null ) {
return null;
}
final Object o = ds.getValue( runtime, element );
if ( o == null ) {
return null;
}
if ( o instanceof URL ) {
// a valid url is found, lookup the url in the cache, maybe the image is loaded and
// still there.
final URL url = (URL) o;
final String urlString = String.valueOf( url );
if ( failureCache.contains( urlString ) ) {
return null;
}
try {
final ResourceManager resManager = runtime.getProcessingContext().getResourceManager();
final Resource resource = resManager.createDirectly( url, DrawableWrapper.class );
return resource.getResource();
} catch ( ResourceException e ) {
if ( DrawableLoadFilter.logger.isDebugEnabled() ) {
DrawableLoadFilter.logger.debug( "Error while loading the drawable from " + url, e );
} else if ( DrawableLoadFilter.logger.isWarnEnabled() ) {
DrawableLoadFilter.logger.warn( "Error while loading the drawable from " + url + ": " + e.getMessage() );
}
failureCache.add( urlString );
return null;
}
} else if ( o instanceof byte[] ) {
try {
final ResourceManager resManager = runtime.getProcessingContext().getResourceManager();
final Resource resource = resManager.createDirectly( o, DrawableWrapper.class );
return resource.getResource();
} catch ( ResourceException e ) {
if ( DrawableLoadFilter.logger.isDebugEnabled() ) {
DrawableLoadFilter.logger.debug( "Error while loading the drawable from byte[]", e );
} else if ( DrawableLoadFilter.logger.isWarnEnabled() ) {
DrawableLoadFilter.logger.warn( "Error while loading the drawable from byte[]: " + e.getMessage() );
}
return null;
}
} else if ( o instanceof Blob ) {
try {
final Blob b = (Blob) o;
final byte[] data = b.getBytes( 1, (int) b.length() );
final ResourceManager resManager = runtime.getProcessingContext().getResourceManager();
final Resource resource = resManager.createDirectly( data, DrawableWrapper.class );
return resource.getResource();
} catch ( Exception e ) {
if ( DrawableLoadFilter.logger.isDebugEnabled() ) {
DrawableLoadFilter.logger.warn( "Error while loading the drawable from an blob", e );
} else if ( DrawableLoadFilter.logger.isWarnEnabled() ) {
DrawableLoadFilter.logger.warn( "Error while loading the drawable from an blob: " + e );
}
return null;
}
} else {
return null;
}
}
/**
* Returns the data source for the filter.
*
* @return The data source.
*/
public DataSource getDataSource() {
return source;
}
/**
* Sets the data source.
*
* @param ds
* The data source.
*/
public void setDataSource( final DataSource ds ) {
if ( ds == null ) {
throw new NullPointerException();
}
source = ds;
}
/**
* Clones the filter.
*
* @return a clone.
* @throws CloneNotSupportedException
* this should never happen.
*/
public DrawableLoadFilter clone() throws CloneNotSupportedException {
final DrawableLoadFilter il = (DrawableLoadFilter) super.clone();
il.failureCache = (HashSet<String>) failureCache.clone();
if ( source != null ) {
il.source = source.clone();
}
return il;
}
/**
* A helper method that is called during the de-serialization process.
*
* @param in
* the serialization input stream.
* @throws IOException
* if an IOError occurs.
* @throws ClassNotFoundException
* if a dependent class cannot be found.
*/
private void readObject( final ObjectInputStream in ) throws IOException, ClassNotFoundException {
in.defaultReadObject();
failureCache = new HashSet<String>();
}
}