/*
* 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.libraries.xmlns.parser;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.libraries.base.util.ObjectUtilities;
import org.pentaho.reporting.libraries.resourceloader.DependencyCollector;
import org.pentaho.reporting.libraries.resourceloader.FactoryParameterKey;
import org.pentaho.reporting.libraries.resourceloader.Resource;
import org.pentaho.reporting.libraries.resourceloader.ResourceException;
import org.pentaho.reporting.libraries.resourceloader.ResourceKey;
import org.pentaho.reporting.libraries.resourceloader.ResourceLoadingException;
import org.pentaho.reporting.libraries.resourceloader.ResourceManager;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import java.util.HashMap;
import java.util.Map;
/**
* A base class for implementing an {@link org.pentaho.reporting.libraries.xmlns.parser.XmlReadHandler}. This class
* takes care of all the delegation management.
*/
public abstract class AbstractXmlReadHandler implements XmlReadHandler {
private static final Log logger = LogFactory.getLog( AbstractXmlReadHandler.class );
/**
* The root handler.
*/
private RootXmlReadHandler rootHandler;
/**
* The tag name.
*/
private String tagName;
/**
* THe namespace URI.
*/
private String uri;
/**
* A flag indicating the first call.
*/
private boolean firstCall;
/**
* Creates a new handler.
*/
protected AbstractXmlReadHandler() {
}
/**
* Initialises the handler.
*
* @param rootHandler the root handler.
* @param tagName the tag name.
*/
public void init( final RootXmlReadHandler rootHandler,
final String uri,
final String tagName ) throws SAXException {
if ( rootHandler == null ) {
throw new NullPointerException( "Root handler must not be null" );
}
if ( tagName == null ) {
throw new NullPointerException( "Tag name must not be null" );
}
this.uri = uri;
this.rootHandler = rootHandler;
this.tagName = tagName;
this.firstCall = true;
}
/**
* This method is called at the start of an element.
*
* @param tagName the tag name.
* @param attrs the attributes.
* @throws SAXException if there is a parsing error.
*/
public final void startElement( final String uri,
final String tagName,
final Attributes attrs )
throws SAXException {
if ( this.firstCall ) {
if ( !this.tagName.equals( tagName ) || !this.uri.equals( uri ) ) {
throw new ParseException(
"Expected <" + this.tagName + ">, found <" + tagName + '>', getLocator() );
}
this.firstCall = false;
startParsing( attrs );
} else {
final XmlReadHandler childHandler = getHandlerForChild( uri, tagName, attrs );
if ( childHandler == null ) {
logger.warn( "Unknown tag <" + uri + ':' + tagName + ">: Start to ignore this element and all of its childs. "
+ getLocatorString() );
logger.debug( this.getClass() );
final IgnoreAnyChildReadHandler ignoreAnyChildReadHandler =
new IgnoreAnyChildReadHandler();
ignoreAnyChildReadHandler.init( getRootHandler(), uri, tagName );
this.rootHandler.recurse( ignoreAnyChildReadHandler, uri, tagName, attrs );
} else {
childHandler.init( getRootHandler(), uri, tagName );
this.rootHandler.recurse( childHandler, uri, tagName, attrs );
}
}
}
/**
* This method is called to process the character data between element tags.
*
* @param ch the character buffer.
* @param start the start index.
* @param length the length.
* @throws SAXException if there is a parsing error.
*/
public void characters( final char[] ch, final int start, final int length )
throws SAXException {
// nothing required
}
/**
* This method is called at the end of an element.
*
* @param tagName the tag name.
* @throws SAXException if there is a parsing error.
*/
public final void endElement( final String uri,
final String tagName ) throws SAXException {
if ( this.tagName.equals( tagName ) && this.uri.equals( uri ) ) {
doneParsing();
this.rootHandler.unwind( uri, tagName );
} else {
throw new ParseException( "Illegal Parser State." + toString(), getLocator() );
}
}
/**
* Computes a string containing the current parse location or an empty string if there is no locator.
*
* @return the location as debug-text.
*/
private String getLocatorString() {
final Locator locator = getLocator();
if ( locator == null ) {
return "";
}
final StringBuffer message = new StringBuffer( 100 );
message.append( " [Location: Line=" );
message.append( locator.getLineNumber() );
message.append( " Column=" );
message.append( locator.getColumnNumber() );
message.append( "] " );
return message.toString();
}
/**
* Starts parsing.
*
* @param attrs the attributes.
* @throws SAXException if there is a parsing error.
*/
protected void startParsing( final Attributes attrs ) throws SAXException {
// nothing required
}
/**
* Done parsing.
*
* @throws SAXException if there is a parsing error.
*/
protected void doneParsing() throws SAXException {
// nothing required
}
/**
* Checks whether the given url denotes the same namespace as the element's namespace.
*
* @param namespaceURI the namespace that should be tested.
* @return true, if the namespace matches the element's namespace,false otherwise.
*/
protected boolean isSameNamespace( final String namespaceURI ) {
return ObjectUtilities.equal( namespaceURI, getUri() );
}
/**
* Returns the handler for a child element.
*
* @param uri the URI of the namespace of the current element.
* @param tagName the tag name.
* @param atts the attributes.
* @return the handler or null, if the tagname is invalid.
* @throws SAXException if there is a parsing error.
*/
protected XmlReadHandler getHandlerForChild( final String uri,
final String tagName,
final Attributes atts )
throws SAXException {
return null;
}
/**
* Returns the tag name.
*
* @return the tag name.
*/
public String getTagName() {
return this.tagName;
}
/**
* Returns the uri of the element. The URI identifies the namespace.
*
* @return the element's URI.
*/
public String getUri() {
return uri;
}
/**
* Returns the root handler for the parsing.
*
* @return the root handler.
*/
public RootXmlReadHandler getRootHandler() {
return this.rootHandler;
}
/**
* Returns the locator as provided by the XML parser. This method may return null if the XML parser has no locator
* support.
*
* @return the locator or null.
*/
public Locator getLocator() {
return rootHandler.getDocumentLocator();
}
/**
* Parses an external file using LibLoader and returns the parsed result as an object of type
* <code>targetClass</code>. The file is given as relative pathname (relative to the current source file). The current
* helper-methods are used as parse-parameters for the external parsing.
*
* @param file the file to be parsed.
* @param targetClass the target type of the parse operation.
* @return the result, never null.
* @throws ParseException if parsing the result failed for some reason.
* @throws ResourceLoadingException if there was an IO error loading the resource.
* @see #deriveParseParameters()
* @see #performExternalParsing(String, Class, Map)
*/
protected Object performExternalParsing( final String file, final Class targetClass )
throws ParseException, ResourceLoadingException {
return performExternalParsing( file, targetClass, deriveParseParameters() );
}
/**
* Parses an external file using LibLoader and returns the parsed result as an object of type
* <code>targetClass</code>. The file is given as relative pathname (relative to the current source file). The current
* helper-methods are used as parse-parameters for the external parsing.
*
* @param file the file to be parsed.
* @param targetClass the target type of the parse operation.
* @param map the map of parse parameters.
* @return the result, never null.
* @throws ParseException if parsing the result failed for some reason.
* @throws ResourceLoadingException if there was an IO error loading the resource.
* @see #deriveParseParameters()
*/
protected Object performExternalParsing( final String file, final Class targetClass, final Map map )
throws ParseException, ResourceLoadingException {
try {
final ResourceManager resourceManager = rootHandler.getResourceManager();
final ResourceKey source = rootHandler.getSource();
final ResourceKey target = resourceManager.deriveKey( source, file, map );
final DependencyCollector dc = rootHandler.getDependencyCollector();
final Resource resource = resourceManager.create( target, rootHandler.getContext(), targetClass );
dc.add( resource );
return resource.getResource();
} catch ( ResourceLoadingException rle ) {
throw rle;
} catch ( ResourceException e ) {
throw new ParseException( "Failure while loading data: " + file, e, getLocator() );
}
}
/**
* Creates a working copy of the current parse state.
*
* @return the derived parse-parameters.
* @noinspection ObjectAllocationInLoop as this is a cloning operation.
*/
protected Map deriveParseParameters() {
final RootXmlReadHandler rootHandler = getRootHandler();
final HashMap map = new HashMap();
final String[] names = rootHandler.getHelperObjectNames();
final int length = names.length;
for ( int i = 0; i < length; i++ ) {
final String name = names[ i ];
final FactoryParameterKey key = new FactoryParameterKey( name );
map.put( key, rootHandler.getHelperObject( name ) );
}
return map;
}
}