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package javax.faces.webapp;

import javax.el.ValueExpression;
import javax.faces.FactoryFinder;
import javax.faces.application.Application;
import javax.faces.application.ApplicationFactory;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;

import java.text.MessageFormat;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

/**
 * 
 * <p>supported filters: <code>package</code> and
 * <code>protection</code>.</p>
 */

 class MessageFactory {

    private static final String MOJARRA_RESOURCE_BASENAME =
        "com.sun.faces.resources.Messages";

    private MessageFactory() {
    }

    /**
     * @see #getMessage(String, Object...)
     * @param severity set a custom severity
     */
     static FacesMessage getMessage(String messageId,
                                                FacesMessage.Severity severity,
                                                Object... params) {
        FacesMessage message = getMessage(messageId, params);
        message.setSeverity(severity);
        return message;
    }


    /**
     * @see #getMessage(Locale, String, Object...)
     * @param severity set a custom severity
     */
     static FacesMessage getMessage(Locale locale,
                                                String messageId,
                                                FacesMessage.Severity severity,
                                                Object... params) {
        FacesMessage message = getMessage(locale, messageId, params);
        message.setSeverity(severity);
        return message;
    }


    /**
     * @see #getMessage(FacesContext, String, Object...)
     * @param severity set a custom severity
     */
     static FacesMessage getMessage(FacesContext context,
                                                String messageId,
                                                FacesMessage.Severity severity,
                                                Object... params) {
        FacesMessage message = getMessage(context, messageId, params);
        message.setSeverity(severity);
        return message;
    }

   
    /**
     * <p>This version of getMessage() is used for localizing implementation
     * specific messages.</p>
     *
     * @param messageId - the key of the message in the resource bundle
     * @param params    - substittion parameters
     *
     * @return a localized <code>FacesMessage</code> with the severity
     *  of FacesMessage.SEVERITY_ERROR
     */
      static FacesMessage getMessage(String messageId, 
                                                 Object... params) {
        Locale locale = null;
        FacesContext context = FacesContext.getCurrentInstance();
        // context.getViewRoot() may not have been initialized at this point.
        if (context != null && context.getViewRoot() != null) {
            locale = context.getViewRoot().getLocale();
            if (locale == null) {
                locale = Locale.getDefault();
            }
        } else {
            locale = Locale.getDefault();
        }
        
        return getMessage(locale, messageId, params);
    }

     /**
      * <p>Creates and returns a FacesMessage for the specified Locale.</p>
      *
      * @param locale    - the target <code>Locale</code>
      * @param messageId - the key of the message in the resource bundle
      * @param params    - substittion parameters
      *
      * @return a localized <code>FacesMessage</code> with the severity
      *  of FacesMessage.SEVERITY_ERROR
      */
      static FacesMessage getMessage(Locale locale, 
                                                 String messageId, 
                                                 Object... params) {       
        String summary = null;
        String detail = null;       
        ResourceBundle bundle;
        String bundleName;

        // see if we have a user-provided bundle
        Application app = getApplication();
	Class appClass = app.getClass();
        if (null != (bundleName = app.getMessageBundle())) {
            if (null != 
                (bundle = 
                    ResourceBundle.getBundle(bundleName, locale,
				     getCurrentLoader(appClass)))) {
                // see if we have a hit
                try {
                    summary = bundle.getString(messageId);
                    detail = bundle.getString(messageId + "_detail");
                }
                catch (MissingResourceException e) {
                    // ignore
                }
            }
        }
    
        // we couldn't find a summary in the user-provided bundle
        if (null == summary) {
            // see if we have a summary in the app provided bundle
            bundle = ResourceBundle.getBundle(FacesMessage.FACES_MESSAGES, 
                                              locale,
                                              getCurrentLoader(appClass));
            if (null == bundle) {
                throw new NullPointerException();
            }
            // see if we have a hit
            try {
                summary = bundle.getString(messageId);
                detail = bundle.getString(messageId + "_detail");
            } catch (MissingResourceException e) {
                // ignore
            }
        }

        // no hit found in the standard javax.faces.Messages bundle.
        // check the Mojarra resources
        if (summary == null) {
            // see if we have a summary in the app provided bundle
            bundle = ResourceBundle.getBundle(MOJARRA_RESOURCE_BASENAME,
                                              locale,
                                              getCurrentLoader(appClass));
            if (null == bundle) {
                throw new NullPointerException();
            }
            // see if we have a hit
            try {
                summary = bundle.getString(messageId);
            } catch (MissingResourceException e) {
                return null;
            }
        }

        // At this point, we have a summary and a bundle.     
        FacesMessage ret = new BindingFacesMessage(locale, summary, detail, params);
        ret.setSeverity(FacesMessage.SEVERITY_ERROR);
        return (ret);
    }


    /**
     * <p>Creates and returns a FacesMessage for the specified Locale.</p>
     *
     * @param context   - the <code>FacesContext</code> for the current request
     * @param messageId - the key of the message in the resource bundle
     * @param params    - substittion parameters
     *
     * @return a localized <code>FacesMessage</code> with the severity
     *  of FacesMessage.SEVERITY_ERROR
     */
     static FacesMessage getMessage(FacesContext context, 
                                                String messageId,
                                                Object... params) {
                                                
        if (context == null || messageId == null ) {
            throw new NullPointerException(" context " 
                + context 
                + " messageId " 
                + messageId);
        }
        Locale locale;
        // viewRoot may not have been initialized at this point.
        if (context.getViewRoot() != null) {
            locale = context.getViewRoot().getLocale();
        } else {
            locale = Locale.getDefault();
        }
        
        if (null == locale) {
            throw new NullPointerException(" locale is null ");
        }
        
        FacesMessage message = getMessage(locale, messageId, params);
        if (message != null) {
            return message;
        }
        locale = Locale.getDefault();
        return (getMessage(locale, messageId, params));
    }  
                       

    /**
     * <p>Returns the <code>label</code> property from the specified
     * component.</p>
     *
     * @param context   - the <code>FacesContext</code> for the current request
     * @param component - the component of interest
     *
     * @return the label, if any, of the component
     */
     static Object getLabel(FacesContext context, 
                                        UIComponent component) {
                                        
        Object o = component.getAttributes().get("label");
        if (o == null || (o instanceof String && ((String) o).length() == 0)) {
            o = component.getValueExpression("label");
        }
        // Use the "clientId" if there was no label specified.
        if (o == null) {
            o = component.getClientId(context);
        }
        return o;
    }

    protected static Application getApplication() {
        FacesContext context = FacesContext.getCurrentInstance();
        if (context != null) {
            return (FacesContext.getCurrentInstance().getApplication());
        }
        ApplicationFactory afactory = (ApplicationFactory)
            FactoryFinder.getFactory(FactoryFinder.APPLICATION_FACTORY);
        return (afactory.getApplication());
    }

    protected static ClassLoader getCurrentLoader(Class fallbackClass) {
        ClassLoader loader =
            Thread.currentThread().getContextClassLoader();
        if (loader == null) {
            loader = fallbackClass.getClassLoader();
        }
        return loader;
    }

    /**
     * This class overrides FacesMessage to provide the evaluation
     * of binding expressions in addition to Strings.
     * It is often the case, that a binding expression may reference
     * a localized property value that would be used as a 
     * substitution parameter in the message.  For example:
     *  <code>#{bundle.userLabel}</code>
     * "bundle" may not be available until the page is rendered.
     * The "late" binding evaluation in <code>getSummary</code> and 
     * <code>getDetail</code> allow the expression to be evaluated
     * when that property is available.
     */
    static class BindingFacesMessage extends FacesMessage {
        BindingFacesMessage(
            Locale locale,
            String messageFormat,
            String detailMessageFormat,
            // array of parameters, both Strings and ValueBindings
            Object[] parameters) {

            super(messageFormat, detailMessageFormat);
            this.locale = locale;
            this.parameters = parameters;
            if (parameters != null) {
                resolvedParameters = new Object[parameters.length];
            }
        }

        public String getSummary() {
            String pattern = super.getSummary();
            resolveBindings();
            return getFormattedString(pattern, resolvedParameters);
        }

        public String getDetail() {
            String pattern = super.getDetail();
            resolveBindings();
            return getFormattedString(pattern, resolvedParameters);
        }

        private void resolveBindings() {
            FacesContext context = null;
            if (parameters != null) {
                for (int i = 0; i < parameters.length; i++) {
                    Object o = parameters[i];
                    if (o instanceof ValueBinding) {
                        if (context == null) {
                            context = FacesContext.getCurrentInstance();
                        }
                        o = ((ValueBinding) o).getValue(context);
                    }
                    if (o instanceof ValueExpression) {
                        if (context == null) {
                            context = FacesContext.getCurrentInstance();
                        }
                        o = ((ValueExpression) o).getValue(context.getELContext());
                    }
                    // to avoid 'null' appearing in message
                    if (o == null) {
                        o = "";
                    }
                    resolvedParameters[i] = o;
                }
            }
        }

        private String getFormattedString(String msgtext, Object[] params) {
            String localizedStr = null;
                                                                                
            if (params == null || msgtext == null ) {
                return msgtext;
            }
            StringBuffer b = new StringBuffer(100);
            MessageFormat mf = new MessageFormat(msgtext);
            if (locale != null) {
                mf.setLocale(locale);
                b.append(mf.format(params));
                localizedStr = b.toString();
            }
            return localizedStr;
        }

        private Locale locale;
        private Object[] parameters;
        private Object[] resolvedParameters;
    }
    
} // end of class MessageFactory
