/*
* Copyright 2012 OmniFaces.
*
* 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.omnifaces.component.input;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import javax.faces.component.FacesComponent;
import javax.faces.context.FacesContext;
import org.omnifaces.component.input.componentidparam.ConditionalWriterListener;
/**
* <p>
* The <code><o:componentIdParam></code> component allows to render just one or more components on a view via a GET
* parameter.
* <p>
* Components can be identified via both their client id or simple component id. Via the former it's possible to
* e.g. render only a specific row in a table. For specific cases, it's possible to render only the parent
* component and omit any children.
* <p>
* Among the use cases for this is creating simple mashups from various JSF based views, and scripts needing to obtain
* markup for specific components on an initial (non-faces) request.
* <p>
* Note that this is a rather specialized component and for many common use cases the user is advised to investigate if the existing
* AJAX and partial page requests in JSF don't already cover the requirements. For the moment this component only supports the
* direct output of the original markup and does not wrap it into any "partial response" envelope.
*
* @since 1.1
* @author Arjan Tijms
*/
@FacesComponent(ComponentIdParam.COMPONENT_TYPE)
public class ComponentIdParam extends ViewParam {
public static final String COMPONENT_TYPE = "org.omnifaces.component.input.ComponentIdParam";
private enum PropertyKeys {
componentIdName, clientIdName, renderChildren
}
@Override
public void decode(FacesContext context) {
List<String> componentIds = getRequestValues(context, PropertyKeys.componentIdName);
List<String> clientIds = getRequestValues(context, PropertyKeys.clientIdName);
boolean renderChildren = getBooleanAttribute(PropertyKeys.renderChildren);
// Installs a PhaseListener on the view root that will replace the response writer before
// and after rendering with one that only renders when the current component has one of the Ids
// that we receive from the request here.
if (!componentIds.isEmpty() || !clientIds.isEmpty()) {
context.getViewRoot().addPhaseListener(new ConditionalWriterListener(context, componentIds, clientIds, renderChildren));
}
}
@Override
public void processValidators(FacesContext context) {
// NOOP. This component doesn't have a model value anyway.
}
@Override
public void processUpdates(FacesContext context) {
// NOOP. This component doesn't have a model value anyway.
}
/**
* Gets the list of request values for the request parameter names identified by the value of the given property key.
*
* @param context
* FacesContext for the request we are processing
* @param propertyKey
* property that holds the request parameter name for which values are returned.
* @return All values in the request corresponding to the given parameter name
*/
private List<String> getRequestValues(FacesContext context, PropertyKeys propertyKey) {
String componentIdName = (String) getAttributes().get(propertyKey.name());
if (componentIdName != null) {
String[] values = context.getExternalContext().getRequestParameterValuesMap().get(componentIdName);
if (values != null) {
return Arrays.asList(values);
}
}
return Collections.emptyList();
}
/**
* Gets the boolean value for the given property key. Defaults to true if no value is defined.
*
* @param propertyKey
* @return false if the boolean attribute is present and not equal to "true", true otherwise.
*/
private boolean getBooleanAttribute(PropertyKeys propertyKey) {
String attribute = (String) getAttributes().get(propertyKey.name());
if (attribute == null) {
return true;
}
return Boolean.valueOf(attribute);
}
}