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Tuesday, May 29, 2012

Some handy JSF utility methods

Some handy JSF utility methods:

import java.io.*;
import java.text.*;
import java.util.*;
import javax.faces.application.*;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;

import javax.servlet.http.HttpSession;
import oracle.adf.view.faces.model.UploadedFile;


public class JSFUtils {

    private static final String NO_RESOURCE_FOUND = "Missing resource: ";

    /**
       * Method for taking a reference to a JSF binding expression and returning
       * the matching object (or creating it)     
       */
    public static Object resolveExpression(FacesContext ctx,
                                           String expression) {
        Application app = ctx.getApplication();
        ValueBinding bind = app.createValueBinding(expression);
        return bind.getValue(ctx);
    }

    /**
       * Convenience method for resolving a reference to a managed bean by name
       * rather than by expression
       */
    public static Object getManagedBeanValue(FacesContext ctx,
                                             String beanName) {
        StringBuffer buff = new StringBuffer("#{");
        buff.append(beanName);
        buff.append("}");
        return resolveExpression(ctx, buff.toString());
    }

    /**
       * Method for setting a new object into a JSF managed bean
       * Note: will fail silently if the supplied object does
       * not match the type of the managed bean
      */
    public static void setExpressionValue(FacesContext ctx, String expression,
                                          Object newValue) {
        Application app = ctx.getApplication();
        ValueBinding bind = app.createValueBinding(expression);
       
        Class bindClass = bind.getType(ctx);
        if (bindClass.isPrimitive()||bindClass.isInstance(newValue)) {
            bind.setValue(ctx, newValue);
        }
    }

    /**
       * Convenience method for setting the value of a managed bean by name
       * rather than by expression
       */
    public static void setManagedBeanValue(FacesContext ctx, String beanName,
                                           Object newValue) {
        StringBuffer buff = new StringBuffer("#{");
        buff.append(beanName);
        buff.append("}");
        setExpressionValue(ctx, buff.toString(), newValue);
    }


    /**
       * Convenience method for setting Session variables
      */
    public static

    void storeOnSession(FacesContext ctx, String key, Object object) {
        Map sessionState = ctx.getExternalContext().getSessionMap();
        sessionState.put(key, object);
    }

    /**
       * Convenience method for getting Session variables
      */
    public static Object getFromSession(FacesContext ctx, String key) {
        Map sessionState = ctx.getExternalContext().getSessionMap();
        return sessionState.get(key);
    }


    /**
       * Pulls a String resource from the property bundle that
       * is defined under the application <message-bundle> element in
       * the faces config. Respects Locale
       */
    public static String getStringFromBundle(String key) {
        ResourceBundle bundle = getBundle();
        return getStringSafely(bundle, key, null);
    }


    /**
       * Convenience method to construct a <code>FacesMesssage</code>
       * from a defined error key and severity
      */
    public static FacesMessage getMessageFromBundle(String key,
                                                    FacesMessage.Severity severity) {
        ResourceBundle bundle = getBundle();
        String summary = getStringSafely(bundle, key, null);
        String detail = getStringSafely(bundle, key + "_detail", summary);
        FacesMessage message = new FacesMessage(summary, detail);
        message.setSeverity(severity);
        return message;
    }

    /*
       * Internal method to pull out the correct local
       * message bundle
       */

    private static ResourceBundle getBundle() {
        FacesContext ctx = FacesContext.getCurrentInstance();
        UIViewRoot uiRoot = ctx.getViewRoot();
        Locale locale = uiRoot.getLocale();
        ClassLoader ldr = Thread.currentThread().getContextClassLoader();
        return ResourceBundle
        .getBundle(ctx.getApplication().getMessageBundle(), locale, ldr);
    }

    /*
       * Internal method to proxy for resource keys that don't exist
       */

    private static String getStringSafely(ResourceBundle bundle, String key,
                                          String defaultValue) {
        String resource = null;                                         
        try {                                         
            resource = bundle.getString(key);
        }
        catch (MissingResourceException mrex) {
            if (defaultValue != null) {
                resource = defaultValue;
            } else {
                resource = NO_RESOURCE_FOUND + key;
            }
        }
        return resource;
    }
    /**
     *
     * @param msg
     */
    public static void addFacesErrorMessage(String msg) {
        FacesContext ctx = getFacesContext();
        FacesMessage fm = new FacesMessage(FacesMessage.SEVERITY_ERROR,msg,null);
        ctx.addMessage(getRootViewComponentId(),fm);
      }
      /**
     *
     * @return
     */
    public static FacesContext getFacesContext() {
         return FacesContext.getCurrentInstance();
       }
       /**
     *
     * @return
     */
    public static String getRootViewComponentId() {
         return getFacesContext().getViewRoot().getId();
       } 
       /**
     *
     * @param beanname
     * @return
     */
       public static Object getBeanByName(String beanname) {
           FacesContext ctx = getFacesContext();
           Application app = ctx.getApplication();    
           return app.getVariableResolver().resolveVariable(ctx,beanname);
       }
      
       
     
    public static void  addValuesToSession(String key,String value) {
   
        FacesContext context = FacesContext.getCurrentInstance();
        HttpSession session = (HttpSession) context.getExternalContext().getSession(false);
        session.setAttribute(key, value);
       
    }
   
 
}






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