/*
* 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.
*/
package org.apache.wicket.markup.resolver;
import org.apache.wicket.Application;
import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupStream;
/**
* Utility class for {@link IComponentResolver}s
*
* @author igor.vaynberg
*/
public class ComponentResolvers
{
private ComponentResolvers()
{
}
/**
* Attempts to resolve a component using resolvers. Tries resolvers in the component hierarchy
* as well as application-wide.
* <p>
* This method encapsulates the contract of resolving components and should be used any time a
* component needs to be resolved under normal circumstances.
* </p>
*
* @param container
* The container parsing its markup
* @param markupStream
* The current markupStream
* @param tag
* The current component tag while parsing the markup
* @param filter
* A filter for application-wide resolvers
* @return component or {@code null} if not found
*/
public static Component resolve(final MarkupContainer container,
final MarkupStream markupStream, final ComponentTag tag, final ResolverFilter filter)
{
// try to resolve using component hierarchy
Component component = resolveByComponentHierarchy(container, markupStream, tag);
if (component == null)
{
// fallback to application-level resolvers
component = resolveByApplication(container, markupStream, tag, filter);
}
return component;
}
/**
* Attempts to resolve a component via application registered resolvers.
*
* @param container
* @param markupStream
* @param tag
* @param filter
* @return Null, if no component was found
*/
public static Component resolveByApplication(final MarkupContainer container,
final MarkupStream markupStream, final ComponentTag tag, final ResolverFilter filter)
{
for (final IComponentResolver resolver : Application.get()
.getPageSettings()
.getComponentResolvers())
{
if ((filter == null) || (filter.ignoreResolver(resolver) == false))
{
Component component = resolver.resolve(container, markupStream, tag);
if (component != null)
{
return component;
}
}
}
return null;
}
/**
* Attempts to resolve a component via the component hierarchy using resolvers.
*
* @param container
* @param markupStream
* @param tag
* @return Null, if no component was found
*/
public static Component resolveByComponentHierarchy(final MarkupContainer container,
final MarkupStream markupStream, final ComponentTag tag)
{
Component cursor = container;
while (cursor != null)
{
if (cursor instanceof IComponentResolver)
{
IComponentResolver resolver = (IComponentResolver)cursor;
Component component = resolver.resolve(container, markupStream, tag);
if (component != null)
{
return component;
}
}
cursor = cursor.getParent();
}
return null;
}
public interface ResolverFilter
{
/**
*
* @param resolver
* @return true, if resolvers should be skipped
*/
boolean ignoreResolver(IComponentResolver resolver);
}
}