MessageFactory.java

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package guessNumber;

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 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>
 */

public class MessageFactory extends Object {
    //
    // Protected Constants
    //

    //
    // Class Variables
    //

    //
    // Instance Variables
    //

    // Attribute Instance Variables

    // Relationship Instance Variables

    //
    // Constructors and Initializers    
    //

    private MessageFactory() {
    }

    //
    // Class methods
    //

    //
    // General Methods
    //

    /**
     * This version of getMessage() is used in the RI for localizing RI
     * specific messages.
     */

    public 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);
    }

    public static FacesMessage getMessage(Locale locale, String messageId,
                                          Object params[]) {
        FacesMessage result = null;
        String
              summary = null,
              detail = null,
              bundleName = null;
        ResourceBundle bundle = null;

        // see if we have a user-provided bundle
        if (null != (bundleName = getApplication().getMessageBundle())) {
            if (null !=
                (bundle =
                      ResourceBundle.getBundle(bundleName, locale,
                                               getCurrentLoader(bundleName)))) {
                // see if we have a hit
                try {
                    summary = bundle.getString(messageId);
                    detail = bundle.getString(messageId + "_detail");
                }
                catch (MissingResourceException e) {
                }
            }
        }

        // 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(bundleName));
            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) {
            }
        }

        // we couldn't find a summary anywhere!  Return null
        if (null == summary) {
            return null;
        }

        if (null == summary || null == bundle) {
            throw new NullPointerException(" summary " + summary + " bundle " +
                                           bundle);
        }
        // At this point, we have a summary and a bundle.
        // 
        return (new BindingFacesMessage(locale, summary, detail, params));
    }


    //
    // Methods from MessageFactory
    // 
    public static FacesMessage getMessage(FacesContext context,
                                          String messageId) {
        return getMessage(context, messageId, null);
    }

    public static FacesMessage getMessage(FacesContext context,
                                          String messageId,
                                          Object params[]) {
        if (context == null || messageId == null) {
            throw new NullPointerException(" context "
                                           + context
                                           + " messageId "
                                           +
                                           messageId);
        }
        Locale locale = null;
        // viewRoot may not have been initialized at this point.
        if (context != null && context.getViewRoot() != null) {
            locale = context.getViewRoot().getLocale();
        } else {
            locale = Locale.getDefault();
        }
        if (null == locale) {
            throw new NullPointerException(" locale " + locale);
        }
        FacesMessage message = getMessage(locale, messageId, params);
        if (message != null) {
            return message;
        }
        locale = Locale.getDefault();
        return (getMessage(locale, messageId, params));
    }

    public static FacesMessage getMessage(FacesContext context,
                                          String messageId,
                                          Object param0) {
        return getMessage(context, messageId, new Object[]{param0});
    }

    public static FacesMessage getMessage(FacesContext context,
                                          String messageId,
                                          Object param0, Object param1) {
        return getMessage(context, messageId, new Object[]{param0, param1});
    }

    public static FacesMessage getMessage(FacesContext context,
                                          String messageId,
                                          Object param0, Object param1,
                                          Object param2) {
        return getMessage(context, messageId,
                          new Object[]{param0, param1, param2});
    }

    public static FacesMessage getMessage(FacesContext context,
                                          String messageId,
                                          Object param0, Object param1,
                                          Object param2, Object param3) {
        return getMessage(context, messageId,
                          new Object[]{param0, param1, param2, param3});
    }

    // Gets the "label" property from the component.

    public static Object getLabel(FacesContext context,
                                  UIComponent component) {
        Object o = component.getAttributes().get("label");
        if (o == null) {
            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(Object fallbackClass) {
        ClassLoader loader =
              Thread.currentThread().getContextClassLoader();
        if (loader == null) {
            loader = fallbackClass.getClass().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 ValueExpressions
              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 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