http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

// $Id: Source.java 446598 2006-09-15 12:55:40Z jeremias $

package javax.xml.transform;


An object that implements this interface contains the information
needed to act as source input (XML source or transformation instructions).

/**
 * An object that implements this interface contains the information
 * needed to act as source input (XML source or transformation instructions).
 */
public interface Source {

    
Set the system identifier for this Source.

The system identifier is optional if the source does not
get its data from a URL, but it may still be useful to provide one.
The application can use a system identifier, for example, to resolve
relative URIs and to include in error messages and warnings.


Params:
  • systemId – The system identifier as a URL string.
/**
     * Set the system identifier for this Source.
     *
     * <p>The system identifier is optional if the source does not
     * get its data from a URL, but it may still be useful to provide one.
     * The application can use a system identifier, for example, to resolve
     * relative URIs and to include in error messages and warnings.</p>
     *
     * @param systemId The system identifier as a URL string.
     */
    public void setSystemId(String systemId);

    
Get the system identifier that was set with setSystemId.

Returns:The system identifier that was set with setSystemId, or null
if setSystemId was not called.
/**
     * Get the system identifier that was set with setSystemId.
     *
     * @return The system identifier that was set with setSystemId, or null
     * if setSystemId was not called.
     */
    public String getSystemId();
}