What issues, if any, are there from defining an XML empty element to mean true in an XML schema rather than using the built in boolean type?
E.g. representing true as
<myoption /> vs <myoption>true</myoption>
And representing false as
'myoption' element absent vs <myoption>false</myoption>
Best Regards
From a database point of view null is neither true nor false.
What about
<myoption state="true" />
<myoption state="false" />
?
Related
i am having a model below
class MaintenancePersonnel(models.Model):
performed_by=models.ForeignKey(User,on_delete=models.CASCADE)
work_performed=models.ForeignKey(EquipmentMaintenanceSchedule,on_delete=models.CASCADE)
comments=models.TextField(blank=True,null=True)
is_performed=models.BooleanField(default=False)
I want for a given work performed to have only one field that has is_performed False
i have tried using condition but this seems to force only one model to have is_performed equal to false regardless of the work performed
class Meta:
constraints = [
models.UniqueConstraint(fields=['work_performed','is_performed'], condition=models.Q(is_performed=False), name='unique_is_performed_False')
]
Try setting your UniqueConstraint field to just work_performed with the is_performed condition.
models.UniqueConstraint(fields=['work_performed'], condition=models.Q(is_performed=False), name='unique_is_performed_False')
This should limit your models to one work_performed where is_performed is false. It seems similar to the case provided in the docs
Within xp:RadioGroup there is xp:selectItem which requires itemLabel.
Data-Properties of xp:selectItem is either itemValue or value:
itemValue - is the value returned to the server
value - specifies the contest of the selection item (Can be literal string or expression)
Loading values in both value & itemValue throws an error e.g.
<xp:radioGroup id="radioGroup"
layout="lineDirection"
dojoType="dijit/form/RadioButton"
styleClass="zmdi">
<xp:selectItem itemLabel='ssh'
itemValue="serverValue"
value="SelectionContentsValue">
</xp:selectItem>
</xp:radioGroup>
The error thrown is:
Exception
Conversion Error setting value ''{0}'' for ''{1}''.
java.lang.IllegalArgumentException: Conversion Error setting value ''{0}'' for ''{1}''.
com.sun.faces.util.Util.getSelectItems(Util.java:489)
com.sun.faces.renderkit.html_basic.SelectManyCheckboxListRenderer.encodeEnd(SelectManyCheckboxListRenderer.java:130)
com.ibm.xsp.renderkit.html_basic.RadioRenderer.encodeEnd(RadioRenderer.java:48)
com.ibm.xsp.renderkit.ReadOnlyAdapterRenderer.encodeEnd(ReadOnlyAdapterRenderer.java:180)
javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:1005)
com.ibm.xsp.component.UISelectOneEx.encodeEnd(UISelectOneEx.java:331)
com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:858)
Removing the [ value="SelectionContentsValue" ] attribute from the xp:selectItem renders the radioGroup without issue.
ideas? thx
The value property of the is intended to be evaluated to something that is a UISelectItem.
Here, you are assigning it to a String "SelectionContentsValue".
During rendering, the Renderer asks the radioGroup "Please give me your all your selectItems".
It does this by iterating through it's children, and checking if each child is a UISelectItem.
For each UISelectItem that it finds, it evaluates the value property.
If value evaluates to null, it will then check for itemLabel, itemValue etc. and create the selectItem using these properties.
else if value evaluates to a UISelectItem, it will use this UISelectItem
else If value evaluates to something that is not a UISelectItem, it throws an IllegalArgumentException
Your situation is throwing the IllegalArgumentException because you have assigned a String to the 'value' property instead of a UISelectItem
So you should either use the itemLabel, itemValue properties and manually set those options that way. Or instead you can use the value property to compute the selectItem to one that has been prepared in some other place, or is dynamically loaded e.g. a managedBean or scoped variable.
I hope this helps let me know if any questions
Thank you Cameron, you comment sparked an idea to go track down, which I found here:
IBM Domino Designer> IBM Domino Designer 9.0.0> IBM Domino Designer User Guide> Designing XPages applications> Adding controls> Control reference selectItems - Selection Items
» Checkboxes can each checked "true", no mutual exclusivity with checkboxes.
Checkboxes are kinda like Hippies, "It's all cool man".
» Radio buttons are much more finicky:
» Radios require itemLabel with itemValue aliase optional, for each selection option:
» The 'value' data-property is for checkboxes. Value contains pipe-delimited selection values, in an array/vector of checkbox choices.
<xp:checkBoxGroup id="checkBoxGroup1" value="#{document1.fruit}">
<xp:selectItems>
<xp:this.value>
<![CDATA[${javascript:["Apples|apples|Garden of Eden|false","Oranges|oranges"]}]]>
</xp:this.value>
</xp:selectItems>
</xp:checkBoxGroup>
Given the following example xsd snippet:
< xs:attribute name="SEGMENT" default="" use="optional" type="xs:string"/ >
when xjc generates the class containing the SEGMENT bean attribute, the following getter is auto-generated:
public String getSEGMENT() {
if (segment == null) {
return "";
} else {
return segment;
}
}
My question is how do you get it do the same for xs:element objects? In other words, given the following xsd snippet:
< xs:element name="NAME" default="" type="xs:string"/ >
I want to know if I can get xjc to generate the following:
public String getNAME() {
if (name == null) {
return "";
} else {
return name;
}
}
How can this be done?
JAXB doesn't generate the same code for an element with default value as it does for an attribute with default value because the XML schema differentiates between element and attribute defaults:
Default values of both attributes and elements are declared using the default attribute, although this attribute has a slightly different consequence in each case. When an attribute is declared with a default value, the value of the attribute is whatever value appears as the attribute's value in an instance document; if the attribute does not appear in the instance document, the schema processor provides the attribute with a value equal to that of the default attribute. Note that default values for attributes only make sense if the attributes themselves are optional, and so it is an error to specify both a default value and anything other than a value of optional for use.
The schema processor treats defaulted elements slightly differently. When an element is declared with a default value, the value of the element is whatever value appears as the element's content in the instance document; if the element appears without any content, the schema processor provides the element with a value equal to that of the default attribute. However, if the element does not appear in the instance document, the schema processor does not provide the element at all. In summary, the differences between element and attribute defaults can be stated as: Default attribute values apply when attributes are missing, and default element values apply when elements are empty.
You can always count on the default value for a missing attribute (from here the special getter) but there is a catch with a missing element value.
Nonetheless, when you unmarshall an instance, the unmarshaller knows how to handle the default value. See here for details:
Element default values and marshalling
Element default values and unmarshalling
XJC won't add the getter code or initialize the fields with the default value, so if you need the "null safe check" you can either add it yourself manually after the code is generated by XJC or try to use some plugin to do it automatically:
JAXB 2 Default Value Plugin
CXF XJC Default Value Plugin
I'm storing value expressions in a JSF component with the f:attribute tag, e.g.:
<h:inputText ...>
<f:attribute name="myId1" value="#{bean.prop1}" />
<f:attribute name="myId2" value="#{bean.prop2}" />
<f:attribute name="myId3" value="#{bean.prop3}" />
</h:inputText>
Is there a way to access all of those value expressions programmatically? (without knowlegde of the names myId1, myId2,...)
Section 9.4.2 of the JSF 2.1 specification says that those values are stored "in the component’s ValueExpression Map".
That's the only occurrence of the term "ValueExpression Map" in the complete spec.
How do I access that map?
In the UIcomponent's Method getValueExpression() of the Jboss/Mojarra implementation the map
getStateHelper().get(UIComponentBase.PropertyKeys.bindings)
is used to obtain a single value expression.
I guess that map is a super set of the "ValueExpression Map"?
Can I be sure that all implementations and all inherited (standard) components use that map to store ValueExpressions?
Thanks.
In theory you should be able to see them all by UIComponent#getAttributes():
Map<String, Object> attributes = component.getAttributes();
for (Map.Entry<String, Object> entry : attributes.entrySet()) {
System.out.printf("name=%s, value=%s%n", entry.getKey(), entry.getValue());
}
However, that doesn't work the way as you'd expect. It only returns static attributes. This does not seem to ever going to be fixed/implemented. See also JSF issue 636. I'd suggest to stick to attribtues with predefinied prefix and an incremental numerical suffix, like as you've presented in your example. That's also what I've always used to pass additional information from the component on to custom validators and converters. You can just collect them as follows:
Map<String, Object> attributes = component.getAttributes();
List<Object> values = new ArrayList<Object>();
for (int i = 1; i < Integer.MAX_VALUE; i++) {
Object value = attributes.get("myId" + i);
if (value == null) break;
values.add(value);
}
System.out.println(values);
An alternative to the answer given by BalusC might be to use nested facets or UIParameter components. Facets can be retrieved as a map using getFacets but you probably need to put an additional UIOutput inside each facet to access its value expression.
Nested UIParameters can be accessed by iterating over the components children and checking for instanceof UIParameter. UIParameters have name and value attributes and so could be easily converted to a map.
I have used parameters in a custom component, but I'm not sure how a standard UIInput like in your example reacts to these.
BalusC is right. UIComponent#getAttributes().get(name) gets values from both places - at first from attributes map and then if not found from "value expression map". To put some value you have to call UIComponent#setValueExpression(name, ValueExpression). If value is literal, it gets stored into the attribute map, otherwise into the "value expression map". Everything is ok then.
Does anyone know a way to get the index of the element in a ui:repeat facelets tag?
<ui:repeat id="topTenGrd" var="dream" value="#{dreamModifyBean.topDreams}">
<h:outputText class="dream-title uppercase" value="#{dream.number}. #{dream.title}" />
</ui:repeat>
Specify a value for the "varStatus" attribute:
<ui:repeat id="..." var="..." value="..." varStatus="myVarStatus">
You can then access the loop index via EL:
#{myVarStatus.index}
Additionally, the following properties are available to the varStatus:
begin of type Integer
end of type Integer
index of type int
step of type Integer
even of type boolean
odd of type boolean
first of type boolean
last of type boolean
For more details, see:
https://docs.oracle.com/javaee/7/javaserver-faces-2-2/vdldocs-facelets/ui/repeat.html
The answer by Brian is good but I think it could be a bit more descriptive for information.
We create UI:Repeat
<ui:repeat id="repeatOne" var="listofValues" varStatus="myVarStatus"> </ui:repeat>
Using UI Repeat we can access the values from the variable we associated with the list 'listofValues'.
Using varStatus we can create another variable that holds different type of information. For example using #{myVarStatus.index} in our list to create a table we can use this information for our index on our list.
1.
2.
3.
Of course if you specify your array to start at 0 then so will your list unless you add 1 to each. #{myVarStatus.index + 1}
These are also very useful in 2D arrays that need to use 2 UI:Repeat that are nested.
Property ___Getter_________Description
current getCurrent() The item (from the collection) for the current round of iteration
index getIndex() The zero-based index for the current round of iteration
count getCount() The one-based count for the current round of iteration
first isFirst() Flag indicating whether the current round is the first pass through the iteration
last isLast() Flag indicating whether the current round is the last pass through the iteration
begin getBegin() The value of the begin attribute
end getEnd() The value of the end attribute
step getStep() The value of the step attribute
Additional Documentation with links:
Attributes for the UI:Repeat can be found here.