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Difference between revisions of "EL Variable Support"
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The fragment shows a c:forEach creating a variable called "book" whose value is the ''expression'' <nowiki>"#{BooksBean.books}"</nowiki>. When h:inputText evaluates "book" in its value attribute, the correct instance is evaluated based on the instance of BooksBean.books that was selected for that collection on a particular iteration of the forEach. | The fragment shows a c:forEach creating a variable called "book" whose value is the ''expression'' <nowiki>"#{BooksBean.books}"</nowiki>. When h:inputText evaluates "book" in its value attribute, the correct instance is evaluated based on the instance of BooksBean.books that was selected for that collection on a particular iteration of the forEach. | ||
| − | In order to support symbols like ''book'' at design-time we need to create a new type of symbol called '' | + | In order to support symbols like ''book'' at design-time we need to create a new type of symbol called ''IExpressionVariableInstanceSymbol''. |
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| + | == Expression Instance Symbol == | ||
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| + | Here is the class hierarchy for the new Expression Instance Symbol: | ||
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| + | [[Image:ExpressionVariableInstanceSymbol.png]] | ||
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| + | Notice that this defines ''IExpressionVariableInstanceSymbol'' as a specialization of an IInstanceSymbol, meaning that it is a kind of instance symbol like a managed bean or resource bundle. | ||
Latest revision as of 18:33, 3 October 2006
Background
Here is an example of the use of an EL variable:
<c:forEach var="book" items="\#\{BooksBean.books\}">
<h:inputText id="quantity" value="\#\{book.quantity\}" ... />
</c:forEach>
The fragment shows a c:forEach creating a variable called "book" whose value is the expression "#{BooksBean.books}". When h:inputText evaluates "book" in its value attribute, the correct instance is evaluated based on the instance of BooksBean.books that was selected for that collection on a particular iteration of the forEach.
In order to support symbols like book at design-time we need to create a new type of symbol called IExpressionVariableInstanceSymbol.
Expression Instance Symbol
Here is the class hierarchy for the new Expression Instance Symbol:
Notice that this defines IExpressionVariableInstanceSymbol as a specialization of an IInstanceSymbol, meaning that it is a kind of instance symbol like a managed bean or resource bundle.