/*
* 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 java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.pentaho.reporting.libraries.base.util.ObjectUtilities;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
/**
* 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.
*
* @noinspection ObjectAllocationInLoop as this is a cloning operation.
* @return the derived parse-parameters.
*/
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;
}
}