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java.lang.Objectorg.apache.commons.jxpath.PackageFunctions
public class PackageFunctions
Extension functions provided by Java classes. The class prefix specified in the constructor is used when a constructor or a static method is called. Usually, a class prefix is a package name (hence the name of this class). Let's say, we declared a PackageFunction like this:
We can now use XPaths like:new PackageFunctions("java.util.", "util")
"util:Date.new()"
new java.util.Date()
"util:Collections.singleton('foo')"
java.util.Collections.singleton("foo")
"util:substring('foo', 1, 2)"
"foo".substring(1, 2)
. Note that in
this case, the class prefix is not used. JXPath does not check that
the first parameter of the function (the method target) is in fact
a member of the package described by this PackageFunctions object.If the first argument of a method or constructor is ExpressionContext, the expression context in which the function is evaluated is passed to the method.
There is one PackageFunctions object registered by default with each
JXPathContext. It does not have a namespace and uses no class prefix.
The existence of this object allows us to use XPaths like:
"java.util.Date.new()"
and "length('foo')"
without the explicit registration of any extension functions.
Constructor Summary | |
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PackageFunctions(java.lang.String classPrefix,
java.lang.String namespace)
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Method Summary | |
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Function |
getFunction(java.lang.String namespace,
java.lang.String name,
java.lang.Object[] parameters)
Returns a Function, if any, for the specified namespace, name and parameter types. |
java.util.Set |
getUsedNamespaces()
Returns the namespace specified in the constructor |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public PackageFunctions(java.lang.String classPrefix, java.lang.String namespace)
Method Detail |
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public java.util.Set getUsedNamespaces()
getUsedNamespaces
in interface Functions
public Function getFunction(java.lang.String namespace, java.lang.String name, java.lang.Object[] parameters)
getFunction
in interface Functions
namespace
- - if it is not the same as specified in the
construction, this method returns nullname
- - name of the method, which can one these forms:
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