/*
* 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.taghandler;
import static org.omnifaces.taghandler.DeferredTagHandlerHelper.collectDeferredAttributes;
import static org.omnifaces.taghandler.DeferredTagHandlerHelper.createInstance;
import static org.omnifaces.taghandler.DeferredTagHandlerHelper.getValueExpression;
import static org.omnifaces.util.Components.getLabel;
import java.io.IOException;
import java.io.Serializable;
import javax.el.ELContext;
import javax.el.ValueExpression;
import javax.faces.application.Application;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.ValidatorException;
import javax.faces.view.facelets.ComponentHandler;
import javax.faces.view.facelets.FaceletContext;
import javax.faces.view.facelets.TagAttribute;
import javax.faces.view.facelets.TagHandlerDelegate;
import javax.faces.view.facelets.ValidatorConfig;
import javax.faces.view.facelets.ValidatorHandler;
import org.omnifaces.taghandler.DeferredTagHandlerHelper.DeferredAttributes;
import org.omnifaces.taghandler.DeferredTagHandlerHelper.DeferredTagHandler;
import org.omnifaces.taghandler.DeferredTagHandlerHelper.DeferredTagHandlerDelegate;
import org.omnifaces.util.Messages;
/**
* <p>
* The <code><o:validator></code> is a taghandler that extends the standard <code><f:validator></code> tag
* family with support for deferred value expressions in all attributes. In other words, the validator attributes are
* not evaluated anymore on a per view build time basis, but just on every access like as with UI components.
* <p>
* When you specify for example the standard <code><f:validateLongRange></code> by
* <code>validatorId="javax.faces.LongRange"</code>, then you'll be able to use all its attributes such as
* <code>minimum</code> and <code>maximum</code> as per its documentation, but then with the possibility to supply
* deferred value expressions.
* <pre>
* <o:validator validatorId="javax.faces.LongRange" minimum="#{item.minimum}" maximum="#{item.maximum}" />
* </pre>
* <p>
* The validator ID of all standard JSF validators can be found in
* <a href="http://docs.oracle.com/javaee/7/api/javax/faces/validator/package-summary.html">their javadocs</a>.
* First go to the javadoc of the class of interest, then go to <code>VALIDATOR_ID</code> in its field summary
* and finally click the Constant Field Values link to see the value.
* <p>
* It is also possible to specify the validator message on a per-validator basis using the <code>message</code>
* attribute. Any "{0}" placeholder in the message will be substituted with the label of the referenced input component.
* Note that this attribute is ignored when the parent component has already <code>validatorMessage</code> specified.
* <pre>
* <o:validator validatorId="javax.faces.LongRange" minimum="#{item.minimum}" maximum="#{item.maximum}"
* message="Please enter between #{item.minimum} and #{item.maximum} characters" />
* </pre>
*
* @author Bauke Scholtz
* @see DeferredTagHandlerHelper
*/
public class Validator extends ValidatorHandler implements DeferredTagHandler {
// Constructors ---------------------------------------------------------------------------------------------------
/**
* The constructor.
* @param config The validator config.
*/
public Validator(ValidatorConfig config) {
super(config);
}
// Actions --------------------------------------------------------------------------------------------------------
/**
* Create a {@link javax.faces.validator.Validator} based on the <code>binding</code> and/or
* <code>validatorId</code> attributes as per the standard JSF <code><f:validator></code> implementation and
* collect the render time attributes. Then create an anonymous <code>Validator</code> implementation which wraps
* the created <code>Validator</code> and delegates the methods to it after setting the render time attributes only
* and only if the <code>disabled</code> attribute evaluates <code>true</code> for the current request. Finally set
* the anonymous implementation on the parent component.
* @param context The involved facelet context.
* @param parent The parent component to add the <code>Validator</code> to.
* @throws IOException If something fails at I/O level.
*/
@Override
public void apply(FaceletContext context, UIComponent parent) throws IOException {
if (!ComponentHandler.isNew(parent) && UIComponent.getCompositeComponentParent(parent) == null) {
// If it's not new nor inside a composite component, we're finished.
return;
}
if (!(parent instanceof EditableValueHolder)) {
// It's likely a composite component. TagHandlerDelegate will pickup it and pass the target component back.
super.apply(context, parent);
return;
}
final javax.faces.validator.Validator validator = createInstance(context, this, "validatorId");
final DeferredAttributes attributes = collectDeferredAttributes(context, this, validator);
final ValueExpression disabled = getValueExpression(context, this, "disabled", Boolean.class);
final ValueExpression message = getValueExpression(context, this, "message", String.class);
((EditableValueHolder) parent).addValidator(new DeferredValidator() {
private static final long serialVersionUID = 1L;
@Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
ELContext el = context.getELContext();
if (disabled == null || Boolean.FALSE.equals(disabled.getValue(el))) {
attributes.invokeSetters(el, validator);
try {
validator.validate(context, component, value);
}
catch (ValidatorException e) {
if (message != null) {
String validatorMessage = (String) message.getValue(el);
if (validatorMessage != null) {
String label = getLabel(component);
throw new ValidatorException(Messages.create(validatorMessage, label)
.detail(validatorMessage, label).error().get(), e.getCause());
}
}
throw e;
}
}
}
});
}
@Override
@SuppressWarnings("unchecked")
public <T> T create(Application application, String id) {
return (T) application.createValidator(id);
}
@Override
public TagAttribute getTagAttribute(String name) {
return getAttribute(name);
}
@Override
protected TagHandlerDelegate getTagHandlerDelegate() {
return new DeferredTagHandlerDelegate(this, super.getTagHandlerDelegate());
}
@Override
public boolean isDisabled(FaceletContext context) {
return false; // Let the deferred validator handle it.
}
// Nested classes -------------------------------------------------------------------------------------------------
/**
* So that we can have a serializable validator.
*
* @author Bauke Scholtz
*/
protected static abstract class DeferredValidator implements javax.faces.validator.Validator, Serializable {
private static final long serialVersionUID = 1L;
}
}