/*
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
Redistribution and use in source and binary forms, with or without modifica-
tion, 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 acknowledgment: "This product includes software
developed by the Apache Software Foundation (http://www.apache.org/)."
Alternately, this acknowledgment may appear in the software itself, if
and wherever such third-party acknowledgments normally appear.
4. The names "Apache Cocoon" 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", nor may
"Apache" appear in their name, without prior written permission of the
Apache Software Foundation.
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 ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 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 and was originally created by
Stefano Mazzocchi <stefano@apache.org>. For more information on the Apache
Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.cocoon.components.source.impl;
import java.io.InputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.net.MalformedURLException;
import java.util.Map;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.logger.Logger;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.ServiceSelector;
import org.apache.excalibur.source.SourceException;
import org.apache.excalibur.source.impl.AbstractSource;
import org.apache.cocoon.components.modules.input.InputModule;
import org.apache.commons.jxpath.JXPathContext;
/**
* A <code>Source</code> that takes its content from a
* module.
* <p>The URI syntax is
* "module:<input-module>:<attribute-name>[#XPath]",
* where :
* <ul>
* <li>an input-module name is used for finding an input-module for reading data from</li>,
* <li>"attribute-name" is the name of the attribute found in the module</li>,
* <li>"XPath" is an XPath that is aplied on the object in the
* attribute, by using JXPath.</li>
* </ul>
* </p>
*
* @author <a href="mailto:danielf@nada.kth.se">Daniel Fagerstom</a>
*/
public class ModuleSource
extends AbstractSource {
private final static String SCHEME = "module";
private String attributeType;
private String attributeName;
private String xPath;
private ServiceManager manager;
private Map objectModel;
private Logger logger;
/**
* Create a module source from a 'module:' uri and a the object model.
* <p>The uri is of the form "module:attribute-type:attribute-name#xpath</p>
*/
public ModuleSource( Map objectModel, String uri,
ServiceManager manager, Logger logger )
throws MalformedURLException, SourceException {
this.objectModel = objectModel;
this.manager = manager;
this.logger = logger;
setSystemId( uri );
// Scheme
int start = 0;
int end = uri.indexOf( ':' );
if ( end == -1 )
throw new MalformedURLException("Malformed uri for module source (cannot find scheme) : " + uri);
String scheme = uri.substring( start, end );
if ( !SCHEME.equals( scheme ) )
throw new MalformedURLException("Malformed uri for a module source : " + uri);
setScheme( scheme );
// Attribute type
start = end + 1;
end = uri.indexOf( ':', start );
if ( end == -1 ) {
throw new MalformedURLException("Malformed uri for module source (cannot find attribute type) : " + uri);
}
this.attributeType = uri.substring( start, end );
// Attribute name
start = end + 1;
end = uri.indexOf( '#', start );
if ( end == -1 )
end = uri.length();
if ( end == start )
throw new MalformedURLException("Malformed uri for module source (cannot find attribute name) : " + uri);
this.attributeName = uri.substring( start, end );
// xpath
start = end + 1;
this.xPath = start < uri.length() ? uri.substring( start ) : "";
}
/**
* Return an <code>InputStream</code> object to read from the source.
*
* @throws IOException if I/O error occured.
*/
public InputStream getInputStream() throws IOException, SourceException {
if ( this.logger.isDebugEnabled() ) {
this.logger.debug( "Getting InputStream for " + getURI() );
}
Object obj = getInputAttribute( this.attributeType, this.attributeName );
if ( obj == null )
throw new SourceException( " The attribute: " + this.attributeName +
" is empty" );
if ( !(this.xPath.length() == 0 || this.xPath.equals( "/" )) ) {
JXPathContext context = JXPathContext.newContext( obj );
obj = context.getValue( this.xPath );
if ( obj == null )
throw new SourceException( "the xpath: " + this.xPath +
" applied on the attribute: " +
this.attributeName +
" returns null");
}
if ( obj instanceof InputStream ) {
return (InputStream)obj;
} else if ( obj instanceof String ) {
return new ByteArrayInputStream( ((String)obj).getBytes() );
} else {
throw new SourceException( "The object type: " + obj.getClass() +
" could not be serialized as a InputStream " + obj );
}
}
/**
* Does this source actually exist ?
*
* @return true if the resource exists.
*
*/
public boolean exists() {
boolean exists = false;
try {
exists = getInputAttribute( this.attributeType, this.attributeName ) != null;
} catch ( SourceException e ) {
exists = false;
}
return exists;
}
private Object getInputAttribute( String inputModuleName, String attributeName )
throws SourceException {
Object obj;
ServiceSelector selector = null;
InputModule inputModule = null;
try {
selector = (ServiceSelector) this.manager.lookup( InputModule.ROLE + "Selector" );
inputModule = (InputModule) selector.select( inputModuleName );
obj = inputModule.getAttribute( attributeName, null, this.objectModel );
} catch ( ServiceException e ) {
throw new SourceException( "Could not find an InputModule of the type " +
inputModuleName , e );
} catch ( ConfigurationException e ) {
throw new SourceException( "Could not find an attribute: " + attributeName +
" from the InputModule " + inputModuleName, e );
} finally {
if ( inputModule != null ) selector.release( inputModule );
this.manager.release( selector );
}
return obj;
}
}