I have a form to select exactly one agent from a list. The backing bean decides if the list should be rendered and fills the items of the radio buttons:
<h:selectOneRadio rendered="#{myBean.shoudRender}" value="#{myBean.selectedAgent}" id="agents">
<f:selectItems value="#{myBean.allAgents}" />
</h:selectOneRadio>
Is it 100% sure, that myBean.getShouldRender() will execute before myBean.getAllAgents?
Thanks!
Yes, it will. The UIComponent#encodeAll() will check if isRendered() returns true before continuing with encoding itself and its children.
On the other hand, this suggests that you're performing business logic in the getter of the <f:selectItems>. Otherwise, you wouldn't worry about it at all for the case it returns null or so and never have asked this question in first place. The getter method is the wrong place for performing business logic. You should do that in the (post)constructor or (action)listener method instead. The getter should solely return the already-prepared value.
Thus, this is wrong:
public boolean isShouldRender() {
boolean shouldRender = // Some business logic...
// ...
return shouldRender;
}
public List<Agent> getAllAgents() {
List<Agent> allAgents = // Some business logic...
// ...
return allAgents ;
}
Instead, you should do
// Have properties which you initialize during an event.
private boolean shouldRender;
private List<Agent> allAgents;
public void someEventMethod() { // E.g. postconstruct, action, ajax behavior, value change, etc.
shouldRender = // Some business logic.
allAgents = // Some business logic.
}
// Keep the getters untouched!
public boolean isShouldRender() {
return shouldRender;
}
public List<Agent> getAllAgents() {
return allAgents;
}
See also:
Why JSF calls getters multiple times
I work in a technology called XPages with is based based off of JSF.
In my world at least rendered would be evaluated first. So I think you will be ok.
Related
Let's say I specify an outputText component like this:
<h:outputText value="#{ManagedBean.someProperty}"/>
If I print a log message when the getter for someProperty is called and load the page, it is trivial to notice that the getter is being called more than once per request (twice or three times is what happened in my case):
DEBUG 2010-01-18 23:31:40,104 (ManagedBean.java:13) - Getting some property
DEBUG 2010-01-18 23:31:40,104 (ManagedBean.java:13) - Getting some property
If the value of someProperty is expensive to calculate, this can potentially be a problem.
I googled a bit and figured this is a known issue. One workaround was to include a check and see if it had already been calculated:
private String someProperty;
public String getSomeProperty() {
if (this.someProperty == null) {
this.someProperty = this.calculatePropertyValue();
}
return this.someProperty;
}
The main problem with this is that you get loads of boilerplate code, not to mention private variables that you might not need.
What are the alternatives to this approach? Is there a way to achieve this without so much unnecessary code? Is there a way to stop JSF from behaving in this way?
Thanks for your input!
This is caused by the nature of deferred expressions #{} (note that "legacy" standard expressions ${} behave exactly the same when Facelets is used instead of JSP). The deferred expression is not immediately evaluated, but created as a ValueExpression object and the getter method behind the expression is executed everytime when the code calls ValueExpression#getValue().
This will normally be invoked one or two times per JSF request-response cycle, depending on whether the component is an input or output component (learn it here). However, this count can get up (much) higher when used in iterating JSF components (such as <h:dataTable> and <ui:repeat>), or here and there in a boolean expression like the rendered attribute. JSF (specifically, EL) won't cache the evaluated result of the EL expression at all as it may return different values on each call (for example, when it's dependent on the currently iterated datatable row).
Evaluating an EL expression and invoking a getter method is a very cheap operation, so you should generally not worry about this at all. However, the story changes when you're performing expensive DB/business logic in the getter method for some reason. This would be re-executed everytime!
Getter methods in JSF backing beans should be designed that way that they solely return the already-prepared property and nothing more, exactly as per the Javabeans specification. They should not do any expensive DB/business logic at all. For that the bean's #PostConstruct and/or (action)listener methods should be used. They are executed only once at some point of request-based JSF lifecycle and that's exactly what you want.
Here is a summary of all different right ways to preset/load a property.
public class Bean {
private SomeObject someProperty;
#PostConstruct
public void init() {
// In #PostConstruct (will be invoked immediately after construction and dependency/property injection).
someProperty = loadSomeProperty();
}
public void onload() {
// Or in GET action method (e.g. <f:viewAction action>).
someProperty = loadSomeProperty();
}
public void preRender(ComponentSystemEvent event) {
// Or in some SystemEvent method (e.g. <f:event type="preRenderView">).
someProperty = loadSomeProperty();
}
public void change(ValueChangeEvent event) {
// Or in some FacesEvent method (e.g. <h:inputXxx valueChangeListener>).
someProperty = loadSomeProperty();
}
public void ajaxListener(AjaxBehaviorEvent event) {
// Or in some BehaviorEvent method (e.g. <f:ajax listener>).
someProperty = loadSomeProperty();
}
public void actionListener(ActionEvent event) {
// Or in some ActionEvent method (e.g. <h:commandXxx actionListener>).
someProperty = loadSomeProperty();
}
public String submit() {
// Or in POST action method (e.g. <h:commandXxx action>).
someProperty = loadSomeProperty();
return "outcome";
}
public SomeObject getSomeProperty() {
// Just keep getter untouched. It isn't intented to do business logic!
return someProperty;
}
}
Note that you should not use bean's constructor or initialization block for the job because it may be invoked multiple times if you're using a bean management framework which uses proxies, such as CDI.
If there are for you really no other ways, due to some restrictive design requirements, then you should introduce lazy loading inside the getter method. I.e. if the property is null, then load and assign it to the property, else return it.
public SomeObject getSomeProperty() {
// If there are really no other ways, introduce lazy loading.
if (someProperty == null) {
someProperty = loadSomeProperty();
}
return someProperty;
}
This way the expensive DB/business logic won't unnecessarily be executed on every single getter call.
See also:
Why is the getter called so many times by the rendered attribute?
Invoke JSF managed bean action on page load
How and when should I load the model from database for h:dataTable
How to populate options of h:selectOneMenu from database?
Display dynamic image from database with p:graphicImage and StreamedContent
Defining and reusing an EL variable in JSF page
Measure the render time of a JSF view after a server request
With JSF 2.0 you can attach a listener to a system event
<h:outputText value="#{ManagedBean.someProperty}">
<f:event type="preRenderView" listener="#{ManagedBean.loadSomeProperty}" />
</h:outputText>
Alternatively you can enclose the JSF page in an f:view tag
<f:view>
<f:event type="preRenderView" listener="#{ManagedBean.loadSomeProperty}" />
.. jsf page here...
<f:view>
I have written an article about how to cache JSF beans getter with Spring AOP.
I create a simple MethodInterceptor which intercepts all methods annotated with a special annotation:
public class CacheAdvice implements MethodInterceptor {
private static Logger logger = LoggerFactory.getLogger(CacheAdvice.class);
#Autowired
private CacheService cacheService;
#Override
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
String key = methodInvocation.getThis() + methodInvocation.getMethod().getName();
String thread = Thread.currentThread().getName();
Object cachedValue = cacheService.getData(thread , key);
if (cachedValue == null){
cachedValue = methodInvocation.proceed();
cacheService.cacheData(thread , key , cachedValue);
logger.debug("Cache miss " + thread + " " + key);
}
else{
logger.debug("Cached hit " + thread + " " + key);
}
return cachedValue;
}
public CacheService getCacheService() {
return cacheService;
}
public void setCacheService(CacheService cacheService) {
this.cacheService = cacheService;
}
}
This interceptor is used in a spring configuration file:
<bean id="advisor" class="org.springframework.aop.support.DefaultPointcutAdvisor">
<property name="pointcut">
<bean class="org.springframework.aop.support.annotation.AnnotationMatchingPointcut">
<constructor-arg index="0" name="classAnnotationType" type="java.lang.Class">
<null/>
</constructor-arg>
<constructor-arg index="1" value="com._4dconcept.docAdvance.jsfCache.annotation.Cacheable" name="methodAnnotationType" type="java.lang.Class"/>
</bean>
</property>
<property name="advice">
<bean class="com._4dconcept.docAdvance.jsfCache.CacheAdvice"/>
</property>
</bean>
Hope it will help!
Originally posted in PrimeFaces forum # http://forum.primefaces.org/viewtopic.php?f=3&t=29546
Recently, I have been obsessed evaluating the performance of my app, tuning JPA queries, replacing dynamic SQL queries with named queries, and just this morning, I recognized that a getter method was more of a HOT SPOT in Java Visual VM than the rest of my code (or majority of my code).
Getter method:
PageNavigationController.getGmapsAutoComplete()
Referenced by ui:include in in index.xhtml
Below, you will see that PageNavigationController.getGmapsAutoComplete() is a HOT SPOT (performance issue) in Java Visual VM. If you look further down, on the screen capture, you will see that getLazyModel(), PrimeFaces lazy datatable getter method, is a hot spot too, only when enduser is doing a lot of 'lazy datatable' type of stuff/operations/tasks in the app. :)
See (original) code below.
public Boolean getGmapsAutoComplete() {
switch (page) {
case "/orders/pf_Add.xhtml":
case "/orders/pf_Edit.xhtml":
case "/orders/pf_EditDriverVehicles.xhtml":
gmapsAutoComplete = true;
break;
default:
gmapsAutoComplete = false;
break;
}
return gmapsAutoComplete;
}
Referenced by the following in index.xhtml:
<h:head>
<ui:include src="#{pageNavigationController.gmapsAutoComplete ? '/head_gmapsAutoComplete.xhtml' : (pageNavigationController.gmaps ? '/head_gmaps.xhtml' : '/head_default.xhtml')}"/>
</h:head>
Solution: since this is a 'getter' method, move code and assign value to gmapsAutoComplete prior to method being called; see code below.
/*
* 2013-04-06 moved switch {...} to updateGmapsAutoComplete()
* because performance = 115ms (hot spot) while
* navigating through web app
*/
public Boolean getGmapsAutoComplete() {
return gmapsAutoComplete;
}
/*
* ALWAYS call this method after "page = ..."
*/
private void updateGmapsAutoComplete() {
switch (page) {
case "/orders/pf_Add.xhtml":
case "/orders/pf_Edit.xhtml":
case "/orders/pf_EditDriverVehicles.xhtml":
gmapsAutoComplete = true;
break;
default:
gmapsAutoComplete = false;
break;
}
}
Test results: PageNavigationController.getGmapsAutoComplete() is no longer a HOT SPOT in Java Visual VM (doesn't even show up anymore)
Sharing this topic, since many of the expert users have advised junior JSF developers to NOT add code in 'getter' methods. :)
If you are using CDI, you can use Producers methods.
It will be called many times, but the result of first call is cached in scope of the bean and is efficient for getters that are computing or initializing heavy objects!
See here, for more info.
You could probably use AOP to create some sort of Aspect that cached the results of our getters for a configurable amount of time. This would prevent you from needing to copy-and-paste boilerplate code in dozens of accessors.
If the value of someProperty is
expensive to calculate, this can
potentially be a problem.
This is what we call a premature optimization. In the rare case that a profiler tells you that the calculation of a property is so extraordinarily expensive that calling it three times rather than once has a significant performance impact, you add caching as you describe. But unless you do something really stupid like factoring primes or accessing a databse in a getter, your code most likely has a dozen worse inefficiencies in places you've never thought about.
I would also advice using such Framework as Primefaces instead of stock JSF, they address such issues before JSF team e. g in primefaces you can set partial submit. Otherwise BalusC has explained it well.
It still big problem in JSF. Fo example if you have a method isPermittedToBlaBla for security checks and in your view you have rendered="#{bean.isPermittedToBlaBla} then the method will be called multiple times.
The security check could be complicated e.g . LDAP query etc. So you must avoid that with
Boolean isAllowed = null ... if(isAllowed==null){...} return isAllowed?
and you must ensure within a session bean this per request.
Ich think JSF must implement here some extensions to avoid multiple calls (e.g annotation #Phase(RENDER_RESPONSE) calle this method only once after RENDER_RESPONSE phase...)
So, here is the jsf component:
<h:selectBooleanCheckbox id="cb#{index}" value="backingBean.value" />
And here is a part of the backing bean java:
/**
* getValue is a method which checks if a checkbox is selected or not, using the checkbox ID
*/
public boolean getValue() {
//TODO: get the checkbox id
String checkboxID = ??
if (getCheckedIDs().contains(checkboxID)) {
return true;
}
return false;
}
When the page is loading the checkboxes, I want to check this way if the checkbox is selected or not.
So the question is, what to write instead of ?? to get the ID of the checkbox who called the method?
It's very important that I can use only JSF 1.1, so there are many solutions which won't work with this version.
EDIT: as #Kukeltje correctly notes, the main issue is that the value expression is incorrect. Once you change that, the below is applicable.
You don't need to "calculate" the value ("set" or "unset") of your checkbox. JSF will simply call backingbean.setValue(x) (with x being true or false) depending on whether the checkbox is on or off at that moment (i.e. when you submit the page).
This happens automatically because you said value="#{backingBean.value}".
So in setValue() you simply store the argument, in getValue you return the stored argument. The rest is done by JSF for you.
If you want the checkbox to be on by default, you set the stored value to true.
For example:
private boolean storedValue = true; // or false if you want it to be off by default
public boolean getValue() {
return storedValue;
}
public void setValue(boolean value) {
this.storedValue = value;
}
I have a problem with a p:selectOneMenu, no matter what I do I cannot get JSF to call the setter on the JPA entity. JSF validation fails with this message:
form:location: Validation Error: Value is not valid
I have this working on several other class of the same type (ie, join table classes) but cannot for the life of me get this one working.
If anyone can throw some troubleshooting/debugging tips for this sort of problem it would be greatly appreciated.
Using log statements I have verified the following:
The Conveter is returning correct, non null values.
I have no Bean Validation in my JPA entities.
The setter setLocation(Location location) is never called.
This is the simplest example I can do and it simply will not work:
<h:body>
<h:form id="form">
<p:messages id="messages" autoUpdate="true" />
<p:selectOneMenu id="location" value="#{locationStockList.selected.location}" converter="locationConverter">
<p:ajax event="change" update=":form:lblLocation"/>
<f:selectItems value="#{locationStockList.locationSelection}"/>
</p:selectOneMenu>
</h:form>
</h:body>
Converter:
#FacesConverter(forClass=Location.class, value="locationConverter")
public class LocationConverter implements Converter, Serializable {
private static final Logger logger = Logger.getLogger(LocationConverter.class.getName());
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value.isEmpty())
return null;
try {
Long id = Long.parseLong(value);
Location location = ((LocationManagedBean) context.getApplication().getELResolver().getValue(context.getELContext(), null, "location")).find(id);
logger.log(Level.SEVERE, "Converted {0} to {1}" , new Object[] {value, location});
return location;
} catch (NumberFormatException e) {
return new Location();
}
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
if (value == null || value.toString().isEmpty() || !(value instanceof Location))
return "";
return String.valueOf(((Location) value).getId());
}
}
Console output:
// Getter method
INFO: Current value=ejb.locations.Location[id=null, name=null, latitude=0.0, longitude=0.0]
// Session Bean
INFO: Finding ejb.locations.Location with id=3
// Session Bean
INFO: ### Returning : ejb.locations.Location[id=3, name=mdmd, latitude=4.5, longitude=2.3]
// Converter
SEVERE: Converted 3 to ejb.locations.Location[id=3, name=mdmd, latitude=4.5, longitude=2.3]
// Getter method -> Where did my selected Location go ??
INFO: Current value=ejb.locations.Location[id=null, name=null, latitude=0.0, longitude=0.0]
Validation fails with the message "form:location: Validation Error: Value is not valid"
This error boils down to that the selected item does not match any of the available select item values specified by any nested <f:selectItem(s)> tag during processing of the form submit request.
As part of safeguard against tampered/hacked requests, JSF will reiterate over all available select item values and test if selectedItem.equals(availableItem) returns true for at least one available item value. If no one item value matches, then you'll get exactly this validation error.
This process is under the covers basically as below, whereby bean.getAvailableItems() fictionally represents the entire list of available select items as defined by <f:selectItem(s)>:
String submittedValue = request.getParameter(component.getClientId());
Converter converter = component.getConverter();
Object selectedItem = (converter != null) ? converter.getAsObject(context, component, submittedValue) : submittedValue;
boolean valid = false;
for (Object availableItem : bean.getAvailableItems()) {
if (selectedItem.equals(availableItem)) {
valid = true;
break;
}
}
if (!valid) {
throw new ValidatorException("Validation Error: Value is not valid");
}
So, based on the above logic, this problem can logically have at least the following causes:
The selected item is missing in the list of available items.
The equals() method of the class representing the selected item is missing or broken.
If a custom Converter is involved, then it has returned the wrong object in getAsObject(). Perhaps it's even null.
To solve it:
Ensure that exactly the same list is been preserved during the subsequent request, particularly in case of multiple cascading menus. Making the bean #ViewScoped instead of #RequestScoped should fix it in most cases. Also make sure that you don't perform the business logic in the getter method of <f:selectItem(s)>, but instead in #PostConstruct or an action event (listener) method. If you're relying on specific request parameters, then you'd need to explicitly store them in the #ViewScoped bean, or to re-pass them on subsequent requests by e.g. <f:param>. See also How to choose the right bean scope?
Ensure that the equals() method is implemented right. This is already done right on standard Java types such as java.lang.String, java.lang.Number, etc, but not necessarily on custom objects/beans/entites. See also Right way to implement equals contract. In case you're already using String, make sure that the request character encoding is configured right. If it contains special characters and JSF is configured to render the output as UTF-8 but interpret the input as e.g. ISO-8859-1, then it will fail. See also a.o. Unicode input retrieved via PrimeFaces input components become corrupted.
Debug/log the actions of your custom Converter and fix it accordingly. For guidelines, see also Conversion Error setting value for 'null Converter' In case you're using java.util.Date as available items with <f:convertDateTime>, make sure that you don't forget the full time part in the pattern. See also "Validation Error: Value is not valid" error from f:datetimeConverter.
See also:
Our selectOneMenu wiki page
How to populate options of h:selectOneMenu from database?
Make multiple dependent / cascading selectOneMenu dropdown lists in JSF
If anyone can throw some troubleshooting/debugging tips for this sort of problem it would be greatly appreciated.
Just ask a clear and concrete question here. Do not ask too broad questions ;)
In my case I forgot to implement a correct get/set methods. It happened because I have changed a lot of attributes along the development.
Without a proper get method, JSF can´t recover your selected item, and happens what BalusC said at item 1 of his answer:
1 . The selected item is missing in the list of available items. This can happen if the list of available items is served by a request scoped bean which is not properly reinitialized on subsequent request, or is incorrectly doing the business job inside a getter method which causes it to return a different list in some way.
This can be a Converter Issue or else DTO issue.
Try to solve this, by adding hashCode() and equals() methods in your object DTO; In the above scenario you can generate these methods within the Location object class which indicate as the 'DTO' here.
Example:
#Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + (int) (id ^ (id >>> 32));
return result;
}
#Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Location other = (Location) obj;
if (id != other.id)
return false;
return true;
}
Please note that the above example is for an 'id' of type 'long'.
Let's say I specify an outputText component like this:
<h:outputText value="#{ManagedBean.someProperty}"/>
If I print a log message when the getter for someProperty is called and load the page, it is trivial to notice that the getter is being called more than once per request (twice or three times is what happened in my case):
DEBUG 2010-01-18 23:31:40,104 (ManagedBean.java:13) - Getting some property
DEBUG 2010-01-18 23:31:40,104 (ManagedBean.java:13) - Getting some property
If the value of someProperty is expensive to calculate, this can potentially be a problem.
I googled a bit and figured this is a known issue. One workaround was to include a check and see if it had already been calculated:
private String someProperty;
public String getSomeProperty() {
if (this.someProperty == null) {
this.someProperty = this.calculatePropertyValue();
}
return this.someProperty;
}
The main problem with this is that you get loads of boilerplate code, not to mention private variables that you might not need.
What are the alternatives to this approach? Is there a way to achieve this without so much unnecessary code? Is there a way to stop JSF from behaving in this way?
Thanks for your input!
This is caused by the nature of deferred expressions #{} (note that "legacy" standard expressions ${} behave exactly the same when Facelets is used instead of JSP). The deferred expression is not immediately evaluated, but created as a ValueExpression object and the getter method behind the expression is executed everytime when the code calls ValueExpression#getValue().
This will normally be invoked one or two times per JSF request-response cycle, depending on whether the component is an input or output component (learn it here). However, this count can get up (much) higher when used in iterating JSF components (such as <h:dataTable> and <ui:repeat>), or here and there in a boolean expression like the rendered attribute. JSF (specifically, EL) won't cache the evaluated result of the EL expression at all as it may return different values on each call (for example, when it's dependent on the currently iterated datatable row).
Evaluating an EL expression and invoking a getter method is a very cheap operation, so you should generally not worry about this at all. However, the story changes when you're performing expensive DB/business logic in the getter method for some reason. This would be re-executed everytime!
Getter methods in JSF backing beans should be designed that way that they solely return the already-prepared property and nothing more, exactly as per the Javabeans specification. They should not do any expensive DB/business logic at all. For that the bean's #PostConstruct and/or (action)listener methods should be used. They are executed only once at some point of request-based JSF lifecycle and that's exactly what you want.
Here is a summary of all different right ways to preset/load a property.
public class Bean {
private SomeObject someProperty;
#PostConstruct
public void init() {
// In #PostConstruct (will be invoked immediately after construction and dependency/property injection).
someProperty = loadSomeProperty();
}
public void onload() {
// Or in GET action method (e.g. <f:viewAction action>).
someProperty = loadSomeProperty();
}
public void preRender(ComponentSystemEvent event) {
// Or in some SystemEvent method (e.g. <f:event type="preRenderView">).
someProperty = loadSomeProperty();
}
public void change(ValueChangeEvent event) {
// Or in some FacesEvent method (e.g. <h:inputXxx valueChangeListener>).
someProperty = loadSomeProperty();
}
public void ajaxListener(AjaxBehaviorEvent event) {
// Or in some BehaviorEvent method (e.g. <f:ajax listener>).
someProperty = loadSomeProperty();
}
public void actionListener(ActionEvent event) {
// Or in some ActionEvent method (e.g. <h:commandXxx actionListener>).
someProperty = loadSomeProperty();
}
public String submit() {
// Or in POST action method (e.g. <h:commandXxx action>).
someProperty = loadSomeProperty();
return "outcome";
}
public SomeObject getSomeProperty() {
// Just keep getter untouched. It isn't intented to do business logic!
return someProperty;
}
}
Note that you should not use bean's constructor or initialization block for the job because it may be invoked multiple times if you're using a bean management framework which uses proxies, such as CDI.
If there are for you really no other ways, due to some restrictive design requirements, then you should introduce lazy loading inside the getter method. I.e. if the property is null, then load and assign it to the property, else return it.
public SomeObject getSomeProperty() {
// If there are really no other ways, introduce lazy loading.
if (someProperty == null) {
someProperty = loadSomeProperty();
}
return someProperty;
}
This way the expensive DB/business logic won't unnecessarily be executed on every single getter call.
See also:
Why is the getter called so many times by the rendered attribute?
Invoke JSF managed bean action on page load
How and when should I load the model from database for h:dataTable
How to populate options of h:selectOneMenu from database?
Display dynamic image from database with p:graphicImage and StreamedContent
Defining and reusing an EL variable in JSF page
Measure the render time of a JSF view after a server request
With JSF 2.0 you can attach a listener to a system event
<h:outputText value="#{ManagedBean.someProperty}">
<f:event type="preRenderView" listener="#{ManagedBean.loadSomeProperty}" />
</h:outputText>
Alternatively you can enclose the JSF page in an f:view tag
<f:view>
<f:event type="preRenderView" listener="#{ManagedBean.loadSomeProperty}" />
.. jsf page here...
<f:view>
I have written an article about how to cache JSF beans getter with Spring AOP.
I create a simple MethodInterceptor which intercepts all methods annotated with a special annotation:
public class CacheAdvice implements MethodInterceptor {
private static Logger logger = LoggerFactory.getLogger(CacheAdvice.class);
#Autowired
private CacheService cacheService;
#Override
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
String key = methodInvocation.getThis() + methodInvocation.getMethod().getName();
String thread = Thread.currentThread().getName();
Object cachedValue = cacheService.getData(thread , key);
if (cachedValue == null){
cachedValue = methodInvocation.proceed();
cacheService.cacheData(thread , key , cachedValue);
logger.debug("Cache miss " + thread + " " + key);
}
else{
logger.debug("Cached hit " + thread + " " + key);
}
return cachedValue;
}
public CacheService getCacheService() {
return cacheService;
}
public void setCacheService(CacheService cacheService) {
this.cacheService = cacheService;
}
}
This interceptor is used in a spring configuration file:
<bean id="advisor" class="org.springframework.aop.support.DefaultPointcutAdvisor">
<property name="pointcut">
<bean class="org.springframework.aop.support.annotation.AnnotationMatchingPointcut">
<constructor-arg index="0" name="classAnnotationType" type="java.lang.Class">
<null/>
</constructor-arg>
<constructor-arg index="1" value="com._4dconcept.docAdvance.jsfCache.annotation.Cacheable" name="methodAnnotationType" type="java.lang.Class"/>
</bean>
</property>
<property name="advice">
<bean class="com._4dconcept.docAdvance.jsfCache.CacheAdvice"/>
</property>
</bean>
Hope it will help!
Originally posted in PrimeFaces forum # http://forum.primefaces.org/viewtopic.php?f=3&t=29546
Recently, I have been obsessed evaluating the performance of my app, tuning JPA queries, replacing dynamic SQL queries with named queries, and just this morning, I recognized that a getter method was more of a HOT SPOT in Java Visual VM than the rest of my code (or majority of my code).
Getter method:
PageNavigationController.getGmapsAutoComplete()
Referenced by ui:include in in index.xhtml
Below, you will see that PageNavigationController.getGmapsAutoComplete() is a HOT SPOT (performance issue) in Java Visual VM. If you look further down, on the screen capture, you will see that getLazyModel(), PrimeFaces lazy datatable getter method, is a hot spot too, only when enduser is doing a lot of 'lazy datatable' type of stuff/operations/tasks in the app. :)
See (original) code below.
public Boolean getGmapsAutoComplete() {
switch (page) {
case "/orders/pf_Add.xhtml":
case "/orders/pf_Edit.xhtml":
case "/orders/pf_EditDriverVehicles.xhtml":
gmapsAutoComplete = true;
break;
default:
gmapsAutoComplete = false;
break;
}
return gmapsAutoComplete;
}
Referenced by the following in index.xhtml:
<h:head>
<ui:include src="#{pageNavigationController.gmapsAutoComplete ? '/head_gmapsAutoComplete.xhtml' : (pageNavigationController.gmaps ? '/head_gmaps.xhtml' : '/head_default.xhtml')}"/>
</h:head>
Solution: since this is a 'getter' method, move code and assign value to gmapsAutoComplete prior to method being called; see code below.
/*
* 2013-04-06 moved switch {...} to updateGmapsAutoComplete()
* because performance = 115ms (hot spot) while
* navigating through web app
*/
public Boolean getGmapsAutoComplete() {
return gmapsAutoComplete;
}
/*
* ALWAYS call this method after "page = ..."
*/
private void updateGmapsAutoComplete() {
switch (page) {
case "/orders/pf_Add.xhtml":
case "/orders/pf_Edit.xhtml":
case "/orders/pf_EditDriverVehicles.xhtml":
gmapsAutoComplete = true;
break;
default:
gmapsAutoComplete = false;
break;
}
}
Test results: PageNavigationController.getGmapsAutoComplete() is no longer a HOT SPOT in Java Visual VM (doesn't even show up anymore)
Sharing this topic, since many of the expert users have advised junior JSF developers to NOT add code in 'getter' methods. :)
If you are using CDI, you can use Producers methods.
It will be called many times, but the result of first call is cached in scope of the bean and is efficient for getters that are computing or initializing heavy objects!
See here, for more info.
You could probably use AOP to create some sort of Aspect that cached the results of our getters for a configurable amount of time. This would prevent you from needing to copy-and-paste boilerplate code in dozens of accessors.
If the value of someProperty is
expensive to calculate, this can
potentially be a problem.
This is what we call a premature optimization. In the rare case that a profiler tells you that the calculation of a property is so extraordinarily expensive that calling it three times rather than once has a significant performance impact, you add caching as you describe. But unless you do something really stupid like factoring primes or accessing a databse in a getter, your code most likely has a dozen worse inefficiencies in places you've never thought about.
I would also advice using such Framework as Primefaces instead of stock JSF, they address such issues before JSF team e. g in primefaces you can set partial submit. Otherwise BalusC has explained it well.
It still big problem in JSF. Fo example if you have a method isPermittedToBlaBla for security checks and in your view you have rendered="#{bean.isPermittedToBlaBla} then the method will be called multiple times.
The security check could be complicated e.g . LDAP query etc. So you must avoid that with
Boolean isAllowed = null ... if(isAllowed==null){...} return isAllowed?
and you must ensure within a session bean this per request.
Ich think JSF must implement here some extensions to avoid multiple calls (e.g annotation #Phase(RENDER_RESPONSE) calle this method only once after RENDER_RESPONSE phase...)
I have a question regarding submitting form content with p:commandbutton that tends to work in the ajax way.
If I have a code like this:
<f:verbatim rendered="#{myBean.constructor}"></f:verbatim >
<h:form prependId="false">
....
.....
<p:commandButton value="#{msg.Add_Parameter_Set}" update="addParameterSetPnl,msgs" action="#{myBean.initNewParametersSet}"/>
</h:form>
When submitting the form with the command button, will the method getContructor from f:verbatim be called (I update different parts of the form)? How can I prevent it from being called?
I thought that submitting a form, only renders the content of the form / the content that was specified by update parameter..
It shouldn't harm. If you're doing expensive stuff in there, then you should move that to the constructor, #PostConstruct or action method of the bean in question, or introduce lazy loading or phase sniffing.
// In Constructor..
public Bean() {
constructed = getItSomehow();
}
// ..or #PostConstruct..
#PostConstruct
public void init() {
constructed = getItSomehow();
}
// ..or action method..
public String submit() {
constructed = getItSomehow();
return "outcome";
}
// ..or lazy loading..
public boolean getConstructed() {
if (constructed == null) constructed = getItSomehow();
return constructed;
}
// ..or phase sniffing (this one updates during render response only).
public boolean getConstructed() {
if (FacesContext.getCurrentInstance().getRenderResponse()) constructed = getItSomehow();
return constructed;
}
See also
Why JSF calls getters multiple times?