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package javax.faces.component;
import java.io.IOException;
import javax.el.ValueExpression;
import javax.faces.FactoryFinder;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.ConverterException;
import javax.faces.render.RenderKit;
import javax.faces.render.RenderKitFactory;
import javax.faces.render.Renderer;
/**
* UIViewParameter represents a
* binding between a request parameter and a model property or {@link UIViewRoot}
* property. This is a bi-directional binding.
*
*
* The {@link javax.faces.view.ViewDeclarationLanguage}
* implementation must cause an instance of this component to appear in
* the view for each occurrence of an <f:viewParam />
* element placed inside of an <f:metadata />
* element. The user must place this facet within the
* UIViewRoot.
* Because this class extends UIInput any actions that
* one would normally take on a UIInput instance are valid
* for instances of this class. Instances of this class participate in
* the regular JSF lifecycle, including on Ajax requests.
*
*
* @since 2.0
*/
public class UIViewParameter extends UIInput {
// ------------------------------------------------------ Manifest Constants
/**
* The standard component type for this component.
*/
public static final String COMPONENT_TYPE = "javax.faces.ViewParameter";
/**
* The standard component family for this component.
*/
public static final String COMPONENT_FAMILY = "javax.faces.ViewParameter";
enum PropertyKeys {
name,
submittedValue
}
// ------------------------------------------------------ Instance Variables
private Renderer inputTextRenderer = null;
// ------------------------------------------------------------ Constructors
/**
* Create a new {@link UIViewParameter} instance with default
* property values.
*/
public UIViewParameter() {
super();
setRendererType(null);
}
// ------------------------------------------------------ Instance Variables
/**
* The raw value is the "implicit" binding for this view parameter. This property
* maintains the submitted value of the view parameter for the duration of the request.
* If the view parameter does not explicitly specify a value expression, then when the
* request ends, this value is stored with the state of this component to use as the
* submitted value on an ensuing postback.
*/
private String rawValue;
// -------------------------------------------------------------- Properties
@Override
public String getFamily() {
return (COMPONENT_FAMILY);
}
/**
* Return the request parameter name
* from which the value is retrieved.
* @since 2.0
*/
public String getName() {
return (String) getStateHelper().eval(PropertyKeys.name);
}
/**
* Set the request parameter name from
* which the value is retrieved.
*
* @param name The new request parameter name.
* @since 2.0
*/
public void setName(String name) {
getStateHelper().put(PropertyKeys.name, name);
}
/**
* Return false. The
* immediate setting is not relevant for view parameters and must be
* assumed to be false.
* @since 2.0
*/
@Override
public boolean isImmediate() {
return false;
}
/**
* Assume
* that the submitted value is
* always a string, but the return type
* from this method is Object..
* @since 2.0
*/
@Override
public Object getSubmittedValue() {
return getStateHelper().get(PropertyKeys.submittedValue);
}
/**
* PENDING (docs) Interesting that submitted value isn't saved by the parent
* @param submittedValue The new submitted value
*/
@Override
public void setSubmittedValue(Object submittedValue) {
getStateHelper().put(PropertyKeys.submittedValue, submittedValue);
}
// ----------------------------------------------------- UIComponent Methods
// This is the "Apply Request Phase" step
// QUESTION should we just override processDecodes() directly?
// ANSWER: In this case, no. We don't want to take responsibility for
// traversing any children we may have in the future.
/**
* Override behavior from superclass to
* pull a value from the incoming request parameter map under the
* name given by {@link #getName} and store it with a call to {@link
* UIInput#setSubmittedValue}.
* @since 2.0
*/
@Override
public void decode(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
// QUESTION can we move forward and support an array? no different than UISelectMany; perhaps need to know
// if the value expression is single or multi-valued
// ANSWER: I'd rather not right now.
String paramValue = context.getExternalContext().getRequestParameterMap().get(getName());
// submitted value will stay as previous value (null on initial request) if a parameter is absent
if (paramValue != null) {
setSubmittedValue(paramValue);
}
rawValue = (String) getSubmittedValue();
setValid(true);
}
/**
* Specialize superclass behavior to treat
* null differently. In this class, a null value
* along with the "required" flag being set to true will
* cause a validation failure.
* @param context
* @since 2.0
*/
@Override
public void processValidators(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
// Skip processing if our rendered flag is false
if (!isRendered()) {
return;
}
// we have to override since UIInput assumes that a null value means don't check
if (getSubmittedValue() == null && isRequired()) {
String requiredMessageStr = getRequiredMessage();
FacesMessage message;
if (null != requiredMessageStr) {
message = new FacesMessage(FacesMessage.SEVERITY_ERROR,
requiredMessageStr,
requiredMessageStr);
} else {
message =
MessageFactory.getMessage(context, REQUIRED_MESSAGE_ID,
MessageFactory.getLabel(
context, this));
}
context.addMessage(getClientId(context), message);
setValid(false);
context.validationFailed();
context.renderResponse();
}
else {
super.processValidators(context);
}
}
/**
* Call through to superclass {@link
* UIInput#updateModel} then take the additional action of pushing
* the value into request scope if and only if the value is not a
* value expression, is valid, and the local value was set on this
* lifecycle execution.
* @since 2.0
*/
@Override
public void updateModel(FacesContext context) {
super.updateModel(context);
if (!hasValueExpression() && isValid() && isLocalValueSet()) {
// QUESTION should this be done even when a value expression is present?
// ANSWER: I don't see why not.
context.getExternalContext().getRequestMap().put(getName(), getLocalValue());
}
}
// This is called during the real "Render Response" phase
/**
* Called specially by {@link
* UIViewRoot#encodeEnd}, this method simply sets the submitted
* value to be the return from {@link #getStringValue}.
* @since 2.0
*/
@Override
public void encodeAll(FacesContext context) throws IOException {
if (context == null) {
throw new NullPointerException();
}
// if there is a value expression, update view parameter w/ latest value after render
// QUESTION is it okay that a null string value may be suppressing the view parameter value?
// ANSWER: I'm not sure.
setSubmittedValue(getStringValue(context));
}
/**
* If the value of this parameter comes
* from a ValueExpression return the value of the
* expression, otherwise, return the local value.
*
* @since 2.0
*/
public String getStringValue(FacesContext context) {
String result = null;
if (hasValueExpression()) {
result = getStringValueFromModel(context);
} else {
result = (null != rawValue) ? rawValue : (String) getValue();
}
return result;
}
/**
* Manually perform standard conversion
* steps to get a string value from the value expression.
*
* @since 2.0
*/
public String getStringValueFromModel(FacesContext context)
throws ConverterException {
ValueExpression ve = getValueExpression("value");
if (ve == null) {
return null;
}
Object currentValue = ve.getValue(context.getELContext());
// If there is a converter attribute, use it to to ask application
// instance for a converter with this identifer.
Converter c = getConverter();
if (c == null) {
// if value is null and no converter attribute is specified, then
// return null (null has meaning for a view parameters; it means remove it).
if (currentValue == null) {
return null;
}
// Do not look for "by-type" converters for Strings
if (currentValue instanceof String) {
return (String) currentValue;
}
// if converter attribute set, try to acquire a converter
// using its class type.
Class converterType = currentValue.getClass();
c = context.getApplication().createConverter(converterType);
// if there is no default converter available for this identifier,
// assume the model type to be String.
if (c == null) {
return currentValue.toString();
}
}
return c.getAsString(context, this, currentValue);
}
/**
* Because this class has no {@link
* Renderer}, leverage the one from the standard HTML_BASIC {@link
* RenderKit} with component-family: javax.faces.Input
* and renderer-type: javax.faces.Text and call its
* {@link Renderer#getConvertedValue} method.
*
* @since 2.0
*/
@Override
protected Object getConvertedValue(FacesContext context, Object submittedValue)
throws ConverterException {
return getInputTextRenderer(context).getConvertedValue(context, this,
submittedValue);
}
private Renderer getInputTextRenderer(FacesContext context) {
if (null == inputTextRenderer) {
RenderKitFactory rkf = (RenderKitFactory)
FactoryFinder.getFactory(FactoryFinder.RENDER_KIT_FACTORY);
RenderKit standard = rkf.getRenderKit(context, RenderKitFactory.HTML_BASIC_RENDER_KIT);
inputTextRenderer = standard.
getRenderer("javax.faces.Input", "javax.faces.Text");
}
assert(null != inputTextRenderer);
return inputTextRenderer;
}
// ----------------------------------------------------- Helper Methods
private boolean hasValueExpression() {
return null != getValueExpression("value");
}
/**
* Inner class to encapsulate a
* UIViewParameter instance so that it may be safely
* referenced regardless of whether or not the current view is the
* same as the view in which this UIViewParameter
* resides.
* @since 2.0
*/
public static class Reference {
private StateHolderSaver saver;
private int indexInParent;
private String viewIdAtTimeOfConstruction;
/**
* Construct a reference to a
* UIViewParameter. This constructor cause the
* {@link StateHolder#saveState} method to be called on
* argument UIViewParameter.
*
* @param context the FacesContextfor this request
* @param indexInParent the index of the
* UIViewParameter in its parent
* UIPanel.
* @param viewIdAtTimeOfConstruction the viewId of the view in
* which the UIViewParameter is included. This may
* not be the same as the viewId from the context
* argument.
*
* @since 2.0
*/
public Reference(FacesContext context,
UIViewParameter param,
int indexInParent,
String viewIdAtTimeOfConstruction) {
this.saver = new StateHolderSaver(context, param);
this.indexInParent = indexInParent;
this.viewIdAtTimeOfConstruction = viewIdAtTimeOfConstruction;
}
/**
* Return the
* UIViewParameter to which this instance refers.
* If the current viewId is the same as the viewId passed to our
* constructor, use the index passed to the constructor to find
* the actual UIViewParameter instance and return
* it. Otherwise, call {@link StateHolder#restoreState} on the
* saved state and return the result.
*
* @param context the FacesContextfor this request
*
* @since 2.0
*/
public UIViewParameter getUIViewParameter(FacesContext context) {
UIViewParameter result = null;
UIViewRoot root = context.getViewRoot();
// If the view root is the same as when we were constructed...
if (this.viewIdAtTimeOfConstruction.equals(root.getViewId())) {
// get the actual view parameter from the tree...
UIComponent metadataFacet = root.getFacet(UIViewRoot.METADATA_FACET_NAME);
result = (UIViewParameter) metadataFacet.getChildren().get(indexInParent);
} else {
// otherwise, use the saved one
result = (UIViewParameter) this.saver.restore(context);
}
return result;
}
}
}