// Copyright 2011 The Apache Software Foundation
//
// Licensed 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.
package org.apache.tapestry5.internal.dynamic;
import java.net.URL;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.xml.namespace.QName;
import org.apache.tapestry5.Binding;
import org.apache.tapestry5.BindingConstants;
import org.apache.tapestry5.Block;
import org.apache.tapestry5.MarkupWriter;
import org.apache.tapestry5.func.F;
import org.apache.tapestry5.func.Flow;
import org.apache.tapestry5.func.Mapper;
import org.apache.tapestry5.func.Worker;
import org.apache.tapestry5.internal.services.XMLTokenStream;
import org.apache.tapestry5.internal.services.XMLTokenType;
import org.apache.tapestry5.ioc.Location;
import org.apache.tapestry5.ioc.Resource;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.ioc.internal.util.InternalUtils;
import org.apache.tapestry5.ioc.internal.util.TapestryException;
import org.apache.tapestry5.runtime.RenderCommand;
import org.apache.tapestry5.runtime.RenderQueue;
import org.apache.tapestry5.services.BindingSource;
import org.apache.tapestry5.services.dynamic.DynamicDelegate;
import org.apache.tapestry5.services.dynamic.DynamicTemplate;
/** Does the heavy lifting for {@link DynamicTemplateParserImpl}. */
public class DynamicTemplateSaxParser
{
private final Resource resource;
private final BindingSource bindingSource;
private final XMLTokenStream tokenStream;
private final Map<String, URL> publicIdToURL = Collections.emptyMap();
private static final Pattern PARAM_ID_PATTERN = Pattern.compile("^param:(\\p{Alpha}\\w*)$",
Pattern.CASE_INSENSITIVE);
private static final Pattern EXPANSION_PATTERN = Pattern.compile("\\$\\{\\s*(.*?)\\s*}");
private static final DynamicTemplateElement END = new DynamicTemplateElement()
{
public void render(MarkupWriter writer, RenderQueue queue, DynamicDelegate delegate)
{
// End the previously started element
writer.end();
}
};
public DynamicTemplateSaxParser(Resource resource, BindingSource bindingSource)
{
this.resource = resource;
this.bindingSource = bindingSource;
this.tokenStream = new XMLTokenStream(resource, publicIdToURL);
}
public DynamicTemplate parse()
{
try
{
tokenStream.parse();
return toDynamicTemplate(root());
}
catch (Exception ex)
{
throw new TapestryException(String.format("Failure parsing dynamic template %s: %s", resource,
InternalUtils.toMessage(ex)), tokenStream.getLocation(), ex);
}
}
// Note the use of static methods; otherwise the compiler sets this$0 to point to the DynamicTemplateSaxParser,
// creating an unwanted reference that keeps the parser from being GCed.
private static DynamicTemplate toDynamicTemplate(List<DynamicTemplateElement> elements)
{
final Flow<DynamicTemplateElement> flow = F.flow(elements).reverse();
return new DynamicTemplate()
{
public RenderCommand createRenderCommand(final DynamicDelegate delegate)
{
final Mapper<DynamicTemplateElement, RenderCommand> toRenderCommand = createToRenderCommandMapper(delegate);
return new RenderCommand()
{
public void render(MarkupWriter writer, RenderQueue queue)
{
Worker<RenderCommand> pushOnQueue = createQueueRenderCommand(queue);
flow.map(toRenderCommand).each(pushOnQueue);
}
};
}
};
}
private List<DynamicTemplateElement> root()
{
List<DynamicTemplateElement> result = CollectionFactory.newList();
while (tokenStream.hasNext())
{
switch (tokenStream.next())
{
case START_ELEMENT:
result.add(element());
break;
case END_DOCUMENT:
// Ignore it.
break;
default:
addTextContent(result);
}
}
return result;
}
private DynamicTemplateElement element()
{
String elementURI = tokenStream.getNamespaceURI();
String elementName = tokenStream.getLocalName();
String blockId = null;
int count = tokenStream.getAttributeCount();
List<DynamicTemplateAttribute> attributes = CollectionFactory.newList();
Location location = getLocation();
for (int i = 0; i < count; i++)
{
QName qname = tokenStream.getAttributeName(i);
// The name will be blank for an xmlns: attribute
String localName = qname.getLocalPart();
if (InternalUtils.isBlank(localName))
continue;
String uri = qname.getNamespaceURI();
String value = tokenStream.getAttributeValue(i);
if (localName.equals("id"))
{
Matcher matcher = PARAM_ID_PATTERN.matcher(value);
if (matcher.matches())
{
blockId = matcher.group(1);
continue;
}
}
Mapper<DynamicDelegate, String> attributeValueExtractor = createCompositeExtractorFromText(value, location);
attributes.add(new DynamicTemplateAttribute(uri, localName, attributeValueExtractor));
}
if (blockId != null)
return block(blockId);
List<DynamicTemplateElement> body = CollectionFactory.newList();
boolean atEnd = false;
while (!atEnd)
{
switch (tokenStream.next())
{
case START_ELEMENT:
// Recurse into this new element
body.add(element());
break;
case END_ELEMENT:
body.add(END);
atEnd = true;
break;
default:
addTextContent(body);
}
}
return createElementWriterElement(elementURI, elementName, attributes, body);
}
private static DynamicTemplateElement createElementWriterElement(final String elementURI, final String elementName,
final List<DynamicTemplateAttribute> attributes, List<DynamicTemplateElement> body)
{
final Flow<DynamicTemplateElement> bodyFlow = F.flow(body).reverse();
return new DynamicTemplateElement()
{
public void render(MarkupWriter writer, RenderQueue queue, DynamicDelegate delegate)
{
// Write the element ...
writer.elementNS(elementURI, elementName);
// ... and the attributes
for (DynamicTemplateAttribute attribute : attributes)
{
attribute.write(writer, delegate);
}
// And convert the DTEs for the direct children of this element into RenderCommands and push them onto
// the queue. This includes the child that will end the started element.
Mapper<DynamicTemplateElement, RenderCommand> toRenderCommand = createToRenderCommandMapper(delegate);
Worker<RenderCommand> pushOnQueue = createQueueRenderCommand(queue);
bodyFlow.map(toRenderCommand).each(pushOnQueue);
}
};
}
private DynamicTemplateElement block(final String blockId)
{
Location location = getLocation();
removeContent();
return createBlockElement(blockId, location);
}
private static DynamicTemplateElement createBlockElement(final String blockId, final Location location)
{
return new DynamicTemplateElement()
{
public void render(MarkupWriter writer, RenderQueue queue, DynamicDelegate delegate)
{
try
{
Block block = delegate.getBlock(blockId);
queue.push((RenderCommand) block);
}
catch (Exception ex)
{
throw new TapestryException(String.format(
"Exception rendering block '%s' as part of dynamic template: %s", blockId,
InternalUtils.toMessage(ex)), location, ex);
}
}
};
}
private Location getLocation()
{
return tokenStream.getLocation();
}
private void removeContent()
{
int depth = 1;
while (true)
{
switch (tokenStream.next())
{
case START_ELEMENT:
depth++;
break;
// The matching end element.
case END_ELEMENT:
depth--;
if (depth == 0)
return;
break;
default:
// Ignore anything else (text, comments, etc.)
}
}
}
void addTextContent(List<DynamicTemplateElement> elements)
{
switch (tokenStream.getEventType())
{
case COMMENT:
elements.add(comment());
break;
case CHARACTERS:
case SPACE:
addTokensForText(elements);
break;
default:
unexpectedEventType();
}
}
private void addTokensForText(List<DynamicTemplateElement> elements)
{
Mapper<DynamicDelegate, String> composite = createCompositeExtractorFromText(tokenStream.getText(),
tokenStream.getLocation());
elements.add(createTextWriterElement(composite));
}
private static DynamicTemplateElement createTextWriterElement(final Mapper<DynamicDelegate, String> composite)
{
return new DynamicTemplateElement()
{
public void render(MarkupWriter writer, RenderQueue queue, DynamicDelegate delegate)
{
String value = composite.map(delegate);
writer.write(value);
}
};
}
private Mapper<DynamicDelegate, String> createCompositeExtractorFromText(String text, Location location)
{
Matcher matcher = EXPANSION_PATTERN.matcher(text);
List<Mapper<DynamicDelegate, String>> extractors = CollectionFactory.newList();
int startx = 0;
while (matcher.find())
{
int matchStart = matcher.start();
if (matchStart != startx)
{
String prefix = text.substring(startx, matchStart);
extractors.add(createTextExtractor(prefix));
}
// Group 1 includes the real text of the expansion, with whitespace
// around the
// expression (but inside the curly braces) excluded.
String expression = matcher.group(1);
extractors.add(createExpansionExtractor(expression, location, bindingSource));
startx = matcher.end();
}
// Catch anything after the final regexp match.
if (startx < text.length())
extractors.add(createTextExtractor(text.substring(startx, text.length())));
if (extractors.size() == 1)
return extractors.get(0);
return creatCompositeExtractor(extractors);
}
private static Mapper<DynamicDelegate, String> creatCompositeExtractor(
final List<Mapper<DynamicDelegate, String>> extractors)
{
return new Mapper<DynamicDelegate, String>()
{
public String map(final DynamicDelegate delegate)
{
StringBuilder builder = new StringBuilder();
for (Mapper<DynamicDelegate, String> extractor : extractors)
{
String value = extractor.map(delegate);
if (value != null)
builder.append(value);
}
return builder.toString();
}
};
}
private DynamicTemplateElement comment()
{
return createCommentElement(tokenStream.getText());
}
private static DynamicTemplateElement createCommentElement(final String content)
{
return new DynamicTemplateElement()
{
public void render(MarkupWriter writer, RenderQueue queue, DynamicDelegate delegate)
{
writer.comment(content);
}
};
}
private static Mapper<DynamicDelegate, String> createTextExtractor(final String content)
{
return new Mapper<DynamicDelegate, String>()
{
public String map(DynamicDelegate delegate)
{
return content;
}
};
}
private static Mapper<DynamicDelegate, String> createExpansionExtractor(final String expression,
final Location location, final BindingSource bindingSource)
{
return new Mapper<DynamicDelegate, String>()
{
public String map(DynamicDelegate delegate)
{
try
{
Binding binding = bindingSource.newBinding("dynamic template binding", delegate
.getComponentResources().getContainerResources(), delegate.getComponentResources(),
BindingConstants.PROP, expression, location);
Object boundValue = binding.get();
return boundValue == null ? null : boundValue.toString();
}
catch (Throwable t)
{
throw new TapestryException(InternalUtils.toMessage(t), location, t);
}
}
};
}
private <T> T unexpectedEventType()
{
XMLTokenType eventType = tokenStream.getEventType();
throw new IllegalStateException(String.format("Unexpected XML parse event %s.", eventType.name()));
}
private static Worker<RenderCommand> createQueueRenderCommand(final RenderQueue queue)
{
return new Worker<RenderCommand>()
{
public void work(RenderCommand value)
{
queue.push(value);
}
};
}
private static RenderCommand toRenderCommand(final DynamicTemplateElement value, final DynamicDelegate delegate)
{
return new RenderCommand()
{
public void render(MarkupWriter writer, RenderQueue queue)
{
value.render(writer, queue, delegate);
}
};
}
private static Mapper<DynamicTemplateElement, RenderCommand> createToRenderCommandMapper(
final DynamicDelegate delegate)
{
return new Mapper<DynamicTemplateElement, RenderCommand>()
{
public RenderCommand map(final DynamicTemplateElement value)
{
return toRenderCommand(value, delegate);
}
};
}
}