package org.apache.velocity.runtime.resource;
/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Velocity", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
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*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Vector;
import java.io.InputStream;
import java.io.IOException;
import org.apache.velocity.Template;
import org.apache.velocity.runtime.Runtime;
import org.apache.velocity.runtime.resource.ResourceFactory;
import org.apache.velocity.runtime.resource.loader.ResourceLoader;
import org.apache.velocity.runtime.resource.loader.ResourceLoaderFactory;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.commons.collections.ExtendedProperties;
/**
* Class to manage the text resource for the Velocity
* Runtime.
*
* @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
* @author <a href="mailto:paulo.gaspar@krankikom.de">Paulo Gaspar</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @version $Id: ResourceManager.java,v 1.29 2001/05/20 21:40:40 geirm Exp $
*/
public class ResourceManager
{
/**
* A template resources.
*/
public static final int RESOURCE_TEMPLATE = 1;
/**
* A static content resource.
*/
public static final int RESOURCE_CONTENT = 2;
/**
* token used to identify the loader internally
*/
private static final String RESOURCE_LOADER_IDENTIFIER = "_RESOURCE_LOADER_IDENTIFIER_";
/**
* Hashtable used to store templates that have been
* processed. Our simple caching mechanism.
*/
private static Hashtable globalCache = new Hashtable();
/**
* The List of templateLoaders that the Runtime will
* use to locate the InputStream source of a template.
*/
private static ArrayList resourceLoaders = new ArrayList();
/**
* This is a list of the template input stream source
* initializers, basically properties for a particular
* template stream source. The order in this list
* reflects numbering of the properties i.e.
*
* <loader-id>.resource.loader.<property> = <value>
*/
private static ArrayList sourceInitializerList = new ArrayList();
/**
* This is a map of public name of the template
* stream source to it's initializer. This is so
* that clients of velocity can set properties of
* a template source stream with its public name.
* So for example, a client could set the
* File.resource.path property and this would
* change the resource.path property for the
* file template stream source.
*/
private static Hashtable sourceInitializerMap = new Hashtable();
/**
* Each loader needs a configuration object for
* its initialization, this flags keeps track of whether
* or not the configuration objects have been created
* for the resource loaders.
*/
private static boolean resourceLoaderInitializersActive = false;
/**
* switch to turn off log notice when a resource is found for
* the first time.
*/
private static boolean logWhenFound = true;
/**
* Initialize the ResourceManager. It is assumed
* that assembleSourceInitializers() has been
* called before this is run.
*/
public static void initialize() throws Exception
{
ResourceLoader resourceLoader;
assembleResourceLoaderInitializers();
for (int i = 0; i < sourceInitializerList.size(); i++)
{
ExtendedProperties configuration = (ExtendedProperties) sourceInitializerList.get(i);
String loaderClass = configuration.getString("class");
if ( loaderClass == null)
{
Runtime.error( "Unable to find '"
+ configuration.getString(RESOURCE_LOADER_IDENTIFIER)
+ ".resource.loader.class' specification in configuation."
+ " This is a critical value. Please adjust configuration.");
continue;
}
resourceLoader = ResourceLoaderFactory.getLoader(loaderClass);
resourceLoader.commonInit(configuration);
resourceLoader.init(configuration);
resourceLoaders.add(resourceLoader);
}
/*
* now see if this is overridden by configuration
*/
logWhenFound = Runtime.getBoolean( Runtime.RESOURCE_MANAGER_LOGWHENFOUND, true );
}
/**
* This will produce a List of Hashtables, each
* hashtable contains the intialization info for
* a particular resource loader. This Hastable
* will be passed in when initializing the
* the template loader.
*/
private static void assembleResourceLoaderInitializers()
{
if (resourceLoaderInitializersActive)
{
return;
}
Vector resourceLoaderNames =
Runtime.getConfiguration().getVector(Runtime.RESOURCE_LOADER);
for (int i = 0; i < resourceLoaderNames.size(); i++)
{
/*
* The loader id might look something like the following:
*
* file.resource.loader
*
* The loader id is the prefix used for all properties
* pertaining to a particular loader.
*/
String loaderID =
resourceLoaderNames.get(i) + "." + Runtime.RESOURCE_LOADER;
ExtendedProperties loaderConfiguration =
Runtime.getConfiguration().subset(loaderID);
/*
* add the loader name token to the initializer if we need it
* for reference later. We can't count on the user to fill
* in the 'name' field
*/
loaderConfiguration.setProperty( RESOURCE_LOADER_IDENTIFIER, resourceLoaderNames.get(i));
/*
* Add resources to the list of resource loader
* initializers.
*/
sourceInitializerList.add(loaderConfiguration);
}
resourceLoaderInitializersActive = true;
}
/**
* Gets the named resource. Returned class type corresponds to specified type
* (i.e. <code>Template</code> to <code>RESOURCE_TEMPLATE</code>).
*
* @param resourceName The name of the resource to retrieve.
* @param resourceType The type of resource (<code>RESOURCE_TEMPLATE</code>,
* <code>RESOURCE_CONTENT</code>, etc.).
* @param encoding The character encoding to use.
* @return Resource with the template parsed and ready.
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
* @throws Exception if a problem in parse
*/
public static Resource getResource(String resourceName, int resourceType, String encoding )
throws ResourceNotFoundException, ParseErrorException, Exception
{
/*
* Check to see if the resource was placed in the cache.
* If it was placed in the cache then we will use
* the cached version of the resource. If not we
* will load it.
*/
Resource resource = (Resource) globalCache.get(resourceName);
if( resource != null)
{
/*
* The resource knows whether it needs to be checked
* or not, and the resource's loader can check to
* see if the source has been modified. If both
* these conditions are true then we must reload
* the input stream and parse it to make a new
* AST for the resource.
*/
if ( resource.requiresChecking() )
{
/*
* touch() the resource to reset the counters
*/
resource.touch();
if( resource.isSourceModified() )
{
/*
* now check encoding info. It's possible that the newly declared
* encoding is different than the encoding already in the resource
* this strikes me as bad...
*/
if (!resource.getEncoding().equals( encoding ) )
{
Runtime.error("Declared encoding for template '" + resourceName
+ "' is different on reload. Old = '" + resource.getEncoding()
+ "' New = '" + encoding );
resource.setEncoding( encoding );
}
try
{
/*
* read how old the resource is _before_
* processing (=>reading) it
*/
long howOldItWas = resource.getResourceLoader().getLastModified( resource );
/*
* read in the fresh stream and parse
*/
resource.process();
/*
* now set the modification info and reset
* the modification check counters
*/
resource.setLastModified( howOldItWas );
}
catch( ResourceNotFoundException rnfe )
{
Runtime.error(
"ResourceManager.getResource() exception: " + rnfe);
throw rnfe;
}
catch( ParseErrorException pee )
{
Runtime.error(
"ResourceManager.getResource() exception: " + pee);
throw pee;
}
catch( Exception eee )
{
Runtime.error(
"ResourceManager.getResource() exception: " + eee);
throw eee;
}
}
}
return resource;
}
else
{
/*
* it's not in the cache
*/
try
{
resource = ResourceFactory.getResource(resourceName, resourceType);
resource.setName( resourceName );
resource.setEncoding( encoding );
/*
* Now we have to try to find the appropriate
* loader for this resource. We have to cycle through
* the list of available resource loaders and see
* which one gives us a stream that we can use to
* make a resource with.
*/
//! Bug this is being run more then once!
long howOldItWas = 0; // Initialize to avoid warnings
ResourceLoader resourceLoader = null;
for (int i = 0; i < resourceLoaders.size(); i++)
{
resourceLoader = (ResourceLoader) resourceLoaders.get(i);
resource.setResourceLoader(resourceLoader);
/*
* catch the ResourceNotFound exception
* as that is ok in our new multi-loader environment
*/
try
{
if (resource.process())
{
/*
* FIXME (gmj)
* moved in here - technically still
* a problem - but the resource needs to be
* processed before the loader can figure
* it out due to to the new
* multi-path support - will revisit and fix
*/
if ( logWhenFound )
{
Runtime.info("ResourceManager : found " + resourceName +
" with loader " + resourceLoader.getClassName());
}
howOldItWas = resourceLoader.getLastModified( resource );
break;
}
}
catch( ResourceNotFoundException rnfe )
{
/*
* that's ok - it's possible to fail in
* multi-loader environment
*/
}
}
/*
* Return null if we can't find a resource.
*/
if (resource.getData() == null)
{
throw new ResourceNotFoundException(
"Unable to find resource '" + resourceName + "'");
}
resource.setLastModified( howOldItWas );
resource.setModificationCheckInterval(
resourceLoader.getModificationCheckInterval());
resource.touch();
/*
* Place the resource in the cache if the resource
* loader says to.
*/
if (resourceLoader.isCachingOn())
{
globalCache.put(resourceName, resource);
}
}
catch( ResourceNotFoundException rnfe2 )
{
Runtime.error(
"ResourceManager : unable to find resource '" + resourceName +
"' in any resource loader.");
throw rnfe2;
}
catch( ParseErrorException pee )
{
Runtime.error(
"ResourceManager.getResource() parse exception: " + pee);
throw pee;
}
catch( Exception ee )
{
Runtime.error(
"ResourceManager.getResource() exception: " + ee);
throw ee;
}
}
return resource;
}
/**
* Gets the named resource. Returned class type corresponds to specified type
* (i.e. <code>Template</code> to <code>RESOURCE_TEMPLATE</code>).
*
* @param resourceName The name of the resource to retrieve.
* @param resourceType The type of resource (<code>RESOURCE_TEMPLATE</code>,
* <code>RESOURCE_CONTENT</code>, etc.).
* @return Resource with the template parsed and ready.
* @throws ResourceNotFoundException if template not found
* from any available source.
* @throws ParseErrorException if template cannot be parsed due
* to syntax (or other) error.
* @throws Exception if a problem in parse
*
* @deprecated Use
* {@link #getResource(String resourceName, int resourceType,
* String encoding )}
*/
public static Resource getResource(String resourceName, int resourceType )
throws ResourceNotFoundException, ParseErrorException, Exception
{
return getResource( resourceName, resourceType, Runtime.ENCODING_DEFAULT);
}
/**
* Determines is a template exists, and returns name of the loader that
* provides it. This is a slightly less hokey way to support
* the Velocity.templateExists() utility method, which was broken
* when per-template encoding was introduced. We can revisit this.
*
* @param resourceName Name of template or content resource
* @return class name of loader than can provide it
*/
public static String getLoaderNameForResource(String resourceName )
{
ResourceLoader resourceLoader = null;
/*
* loop through our loaders...
*/
for (int i = 0; i < resourceLoaders.size(); i++)
{
resourceLoader = (ResourceLoader) resourceLoaders.get(i);
InputStream is = null;
/*
* if we find one that can provide the resource,
* return the name of the loaders's Class
*/
try
{
is=resourceLoader.getResourceStream( resourceName );
if( is != null)
{
return resourceLoader.getClass().toString();
}
}
catch( ResourceNotFoundException e)
{
/*
* this isn't a problem. keep going
*/
}
finally
{
/*
* if we did find one, clean up because we were
* returned an open stream
*/
if (is != null)
{
try
{
is.close();
}
catch( IOException ioe)
{
}
}
}
}
return null;
}
}