Pass changed value from inputText to bean - jsf

Question

I'm trying to pass the changed value of the variable to a bean method:
<h:panelGroup rendered="#{! empty gradesBean.getAllGrades()}">
<h:dataTable value="#{gradesBean.getAllGrades()}" var="g">
<h:column>
<f:facet name="header">#{msg['outputSubject']}</f:facet>
<h:inputText value="#{g.subject}" onchange="#{g.subject}" />
</h:column>
<h:column>
<f:facet name="header">#{msg['outputGrade']}</f:facet>
<h:inputText value="#{g.mark}" onchange="#{g.mark}"/>
</h:column>
<h:column>
<h:form>
<h:commandButton value="#{msg['actionSave']}" action="#{gradesBean.edit(g)}" />
</h:form>
</h:column>
</h:dataTable>
(.........)
</h:panelGroup>
I want the changes of the user he does in the inputText on g.subject and g.mark to be passed to gradesBean.edit(g). When I try to do that somehow the same values of the original values of the both variables are passed. There are getter and setter methods in the respective object
#Named
#ViewScoped
public class GradesBean extends AbstractBean implements Serializable {
private static final long serialVersionUID = 320401008216711886L;
private static final String NO_GRADES_PRESENT = "keine Noten eingetragen";
private static final Logger loggerLogger.getLogger(GradesBean.class);
#Inject
private transient GradeDAO gradeDAO;
#Inject
private UserDAO userDAO;
private Grade grade;
private List<Grade> allGrades;
#PostConstruct
public void init() {
if (!isLoggedIn()) {
return;
}
grade = new Grade();
allGrades = getSession().getUser().getGrades();
}
public Grade getGrade() {
return grade;
}
public List<Grade> getAllGrades() {
return allGrades;
}
public String getGradeAverage() {
final List<BigDecimal> theDecimals = new ArrayList<>(allGrades.size());
for (final Grade g : allGrades) {
theDecimals.add(g.getMark());
}
final Configuration config = Configuration.getDefault();
final int scale = config.getScale();
final RoundingMode roundingMode = config.getRoundingMode();
try {
final BigDecimal average = de.unibremen.st.gradelog.businesslogic.Math
.average(theDecimals, scale, roundingMode);
return average.stripTrailingZeros().toPlainString();
} catch (final ArithmeticException e) {
logger.debug(
"Calculation of grade average has been called without any grades.", e);
return NO_GRADES_PRESENT;
}
}
public String getGradeMedian() {
final List<BigDecimal> theDecimals = new ArrayList<>(allGrades.size());
for (final Grade g : allGrades) {
theDecimals.add(g.getMark());
}
try {
final BigDecimal median = de.unibremen.st.gradelog.businesslogic.Math
.median(theDecimals);
return median.stripTrailingZeros().toPlainString();
} catch (final ArithmeticException e) {
logger.debug(
"Calculation of grades median has been called without any grades.", e);
return NO_GRADES_PRESENT;
}
}
public String save() {
if (!isLoggedIn()) {
return null;
}
final User user = getSession().getUser();
grade.setUser(user);
user.addGrade(grade);
gradeDAO.save(grade);
try {
userDAO.update(user);
} catch (final DuplicateUniqueFieldException e) {
throw new UnexpectedUniqueViolationException(e);
}
init();
return null;
}
public String edit() {
if (!isLoggedIn()) {
return null;
}
assertNotNull(grade);
final User user = getSession().getUser();
gradeDAO.update(grade);
try {
userDAO.update(user);
} catch (final DuplicateUniqueFieldException e) {
throw new UnexpectedUniqueViolationException(e);
}
init();
return null;
}
public String remove(final Grade theGrade) {
if (!isLoggedIn()) {
return null;
}
assertNotNull(theGrade);
final User user = getSession().getUser();
user.removeGrade(theGrade);
gradeDAO.remove(theGrade);
try {
userDAO.update(user);
} catch (final DuplicateUniqueFieldException e) {
throw new UnexpectedUniqueViolationException(e);
}
init();
return null;
}
}`

Answer 1

g.mark and g.subject will already call the corresponding setters on your backing bean class (I assume that public setters getMark() and getSubject() exist).
Since action="#{gradesBean.edit(g)}" is resolved at the server (when the page is first displayed), it will have the original values , not the changed values. Anyway , to see the changed values you can use ajax (f:ajax tag and the corresponding listener attribute should be set). But you don't have to do this. Simply change your handler to
action="#{gradesBean.edit()}" //no argument
and get the latest values from your bean class instance.
I could be more specific if you want.