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JavaServer Faces by Hans Bergsten

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Data Types

A variable is always of a specific Java type. Besides the standard Java types for numeric, Boolean, and text values, the EL provides special support for custom classes developed according to the JavaBeans guidelines, java.util.Map objects, java.util.List objects, and arrays.

Bean properties can be accessed using the special property accessor operator (a dot), and be nested to any length:

#{aBean.aProperty.aPropertyOfTheProperty.andSoOn}

Map entries can be accessed the same way:

#{aMap.aKey}

List and array elements can be accessed using the array accessor operator (square brackets):

#{aList[0]}
#{anArray[0]}
#{anArrayOrList[anExressionWithANumbericValue]}

The array accessor operator can also access bean properties and Map entries. It must be used when the property name is determined by a subexpression, the property name is a reserved word or contains characters used for operators, such as a dot:

#{aMap[param.customerName]}
#{aBean['empty']}
#{aMap['com.mycomp.logo']}

A custom javax.faces.el.PropertyResolver class can extend or modify how the property and element accessor operators behave. See Appendix D for details.

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