org.openmdx.kernel.xml.EntityMapper Maven / Gradle / Ivy
/*
* ==================================================================== Project:
* openMDX, http://www.openmdx.org/ Description: EntityMapper Owner: OMEX AG,
* Switzerland, http://www.omex.ch
* ====================================================================
*
* This software is published under the BSD license as listed below.
*
* Copyright (c) 2004-2015, OMEX AG, Switzerland All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of the openMDX team nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, 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 product includes software developed by other organizations as listed in
* the NOTICE file.
*/
package org.openmdx.kernel.xml;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Hashtable;
import java.util.Map;
import org.openmdx.kernel.loading.Resources;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
/**
* Entity Mapper
*/
public class EntityMapper implements EntityResolver {
/**
* Constructor
*/
private EntityMapper() {
// Avoid instantiation
}
/**
* Helps to identify and transform XRI resource URLs
*/
private static final String RESOURCE_URL_PREFIX = "xri://+resource/";
/**
* The singleton
*/
private static final EntityMapper instance = new EntityMapper();
/**
* Public id mappings
*/
private final Map publicIdMappings =
new Hashtable();
/**
* System id mappings
*/
private final Map systemIdMappings =
new Hashtable();
/**
* Get an entity mapper instance
*
* @return an entity mapper instance
*/
public static EntityResolver getInstance() {
return EntityMapper.instance;
}
/**
* Register a public id mapping
*
* @param publicId
* @param uri
*/
public static void registerPublicId(String publicId, String url) {
EntityMapper.instance.publicIdMappings.put(publicId, url);
}
/**
* Register a system id mapping.
*
* The preferred way is to use registerPublicId instead of the method.
*
* @param systemId
* @param url
*/
public static void registerSystemId(String systemId, String url) {
EntityMapper.instance.systemIdMappings.put(systemId, url);
}
// ------------------------------------------------------------------------
// Implements EntityResolver
// ------------------------------------------------------------------------
/*
* (non-Javadoc)
*
* @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String,
* java.lang.String)
*/
@Override
public InputSource resolveEntity(String publicId, String systemId){
if (publicId != null) {
String url = publicIdMappings.get(publicId);
if (url != null) {
return new InputSource(openStreamFromURI(url));
}
}
if (systemId != null) {
String url = systemIdMappings.get(systemId);
if (url != null) {
return new InputSource(openStreamFromURI(url));
}
}
return null;
}
/**
* Handle xri://+resource-URLs internally
*
* @param uri
* the resource identifier
* @return a stream providing the resource; or null if no such stream can be acquired
*/
private static InputStream openStreamFromURI(
String uri
){
return uri.startsWith(RESOURCE_URL_PREFIX)
? Resources.getResourceAsStream(toResourceName(uri))
: openStreamFromURL(uri);
}
/**
* Open a stream for a given URL
*
* @param uri
* the resource identifier
*
* @return a stream providing the resource; or null if no such stream can be acquired
*/
private static InputStream openStreamFromURL(
String uri
){
try {
return new URL(uri).openStream();
} catch (MalformedURLException exception) {
return null;
} catch (IOException exception) {
return null;
}
}
/**
* Extract the name of a resource from xri://+resource-URL
*
* @param url the uniform locator of the resource
*
* @return the name of a resource
*/
private static String toResourceName(String url) {
return url.substring(RESOURCE_URL_PREFIX.length());
}
}