/*
* $Id: ValidatorTag.java,v 1.26 2007/04/27 22:00:12 ofung Exp $
*/
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package javax.faces.webapp;
import javax.el.ValueExpression;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.Validator;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
/**
* <p><strong>ValidatorTag</strong> is a base class for all JSP custom actions
* that create and register a <code>Validator</code> instance on the
* {@link EditableValueHolder} associated with our most immediate surrounding instance
* of a tag whose implementation class is a subclass of {@link UIComponentTag}.
* To avoid creating duplicate instances when a page is redisplayed,
* creation and registration of a {@link Validator} occurs
* <strong>only</strong> if the corresponding {@link UIComponent} was
* created (by the owning {@link UIComponentTag}) during the execution of the
* current page.</p>
*
* <p>This class may be used directly to implement a generic validator
* registration tag (based on the validator-id specified by the
* <code>id</code> attribute), or as a base class for tag instances that
* support specific {@link Validator} subclasses. This <code>id</code>
* attribute must refer to one of the well known validator-ids, or a
* custom validator-id as defined in a <code>faces-config.xml</code>
* file.</p>
*
* <p>Subclasses of this class must implement the
* <code>createValidator()</code> method, which creates and returns a
* {@link Validator} instance. Any configuration properties that specify
* the limits to be enforced by this {@link Validator} must have been
* set by the <code>createValidator()</code> method. Generally, this occurs
* by copying corresponding attribute values on the tag instance.</p>
*
* <p>This tag creates no output to the page currently being created. It
* is used solely for the side effect of {@link Validator} creation.</p>
*
* @deprecated This has been partially replaced by {@link
* ValidatorELTag}. The remainder of the functionality, namely, the
* binding facility and the implementation of the {@link
* #createValidator} method, is now an implementation detail.
*/
public class ValidatorTag extends TagSupport {
// ---------------------------------------------------------- Static Members
private static final long serialVersionUID = -5562623615418158868L;
// ------------------------------------------------------------- Attributes
/**
* <p>The identifier of the {@link Validator} instance to be created.</p>
*/
private String validatorId = null;
/**
* <p>The {@link ValueExpression} that evaluates to an object that
* implements {@link Validator}.</p>
*/
private String binding = null;
/**
* <p>Set the identifer of the {@link Validator} instance to be created.
*
* @param validatorId The new identifier of the validator instance to be
* created.
*/
public void setValidatorId(String validatorId) {
this.validatorId = validatorId;
}
/**
* <p>Set the expression that will be used to create a {@link ValueExpression}
* that references a backing bean property of the {@link Validator} instance to
* be created.</p>
*
* @param binding The new expression
*
* @throws JspException if a JSP error occurs
*/
public void setBinding(String binding)
throws JspException {
if (binding != null && !UIComponentTag.isValueReference(binding)) {
//PENDING i18n
throw new JspException("Invalid Expression:"+binding);
}
this.binding = binding;
}
// --------------------------------------------------------- Public Methods
/**
* <p>Create a new instance of the specified {@link Validator}
* class, and register it with the {@link UIComponent} instance associated
* with our most immediately surrounding {@link UIComponentTag} instance, if
* the {@link UIComponent} instance was created by this execution of the
* containing JSP page.</p>
*
* @throws JspException if a JSP error occurs
*/
public int doStartTag() throws JspException {
// Locate our parent UIComponentTag
UIComponentClassicTagBase tag =
UIComponentClassicTagBase.getParentUIComponentClassicTagBase(pageContext);
if (tag == null) {
//PENDING i18n
throw new JspException("Not nested in a UIComponentTag Error for tag with handler class:"+
this.getClass().getName());
}
// Nothing to do unless this tag created a component
if (!tag.getCreated()) {
return (SKIP_BODY);
}
UIComponent component = tag.getComponentInstance();
if (component == null) {
//PENDING i18n
throw new JspException("Can't create Component from tag.");
}
if (!(component instanceof EditableValueHolder)) {
// PENDING i18n
throw new JspException("Not nested in a tag of proper type. Error for tag with handler class:"+
this.getClass().getName());
}
Validator validator = createValidator();
if (validator == null) {
//noinspection NonConstantStringShouldBeStringBuffer
String validateError = null;
if (binding != null) {
validateError = binding;
}
if (validatorId != null) {
if (validateError != null) {
validateError += " or " + validatorId;
} else {
validateError = validatorId;
}
}
// PENDING i18n
throw new JspException("Can't create class of type:"+
"javax.faces.validator.Validator from:"+validateError);
}
// Register an instance with the appropriate component
((EditableValueHolder)component).addValidator(validator);
return (SKIP_BODY);
}
/**
* <p>Release references to any acquired resources.
*/
public void release() {
this.id = null;
}
// ------------------------------------------------------ Protected Methods
/**
* <p>Create and return a new {@link Validator} to be registered
* on our surrounding {@link UIComponent}.</p>
*
* @throws JspException if a new instance cannot be created
*/
protected Validator createValidator()
throws JspException {
FacesContext context = FacesContext.getCurrentInstance();
Validator validator = null;
ValueExpression vb = null;
// If "binding" is set, use it to create a validator instance.
if (binding != null) {
try {
vb = context.getApplication().getExpressionFactory().createValueExpression(context.getELContext(),
binding, Object.class);
if (vb != null) {
validator = (Validator)vb.getValue(context.getELContext());
if (validator != null) {
return validator;
}
}
} catch (Exception e) {
throw new JspException(e);
}
}
// If "validatorId" is set, use it to create the validator
// instance. If "validatorId" and "binding" are both set, store the
// validator instance in the value of the property represented by
// the value binding expression.
if (validatorId != null) {
try {
String validatorIdVal = validatorId;
if (UIComponentTag.isValueReference(validatorId)) {
ValueExpression idBinding = context.getApplication().
getExpressionFactory().createValueExpression(context.getELContext(),
validatorId, Object.class);
validatorIdVal = (String)idBinding.getValue(context.getELContext());
}
validator = context.getApplication().createValidator(validatorIdVal);
if (validator != null) {
if (vb != null) {
vb.setValue(context.getELContext(), validator);
}
}
} catch (Exception e) {
throw new JspException(e);
}
}
return validator;
}
}