Examples of org.apache.commons.jxpath.PackageFunctions

org.apache.commons.jxpath.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:

 new PackageFunctions("java.util.", "util")

We can now use XPaths like:

"util:Date.new()": Equivalent to new java.util.Date()
"util:Collections.singleton('foo')": Equivalent to java.util.Collections.singleton("foo")
"util:substring('foo', 1, 2)": Equivalent to "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.

@author Dmitri Plotnikov @version $Revision: 1.10 $ $Date: 2003/03/11 00:59:12 $

            vars.declareVariable("test", new TestFunctions(4, "test"));


            FunctionLibrary lib = new FunctionLibrary();
            lib.addFunctions(new ClassFunctions(TestFunctions.class, "test"));
            lib.addFunctions(new ClassFunctions(TestFunctions2.class, "test"));
            lib.addFunctions(new PackageFunctions("", "call"));
            lib.addFunctions(
                new PackageFunctions(
                    "org.apache.commons.jxpath.ri.compiler.",
                    "jxpathtest"));
            lib.addFunctions(new PackageFunctions("", null));
            context.setFunctions(lib);
            context.getVariables().declareVariable("List.class", List.class);
            context.getVariables().declareVariable("NodeSet.class", NodeSet.class);
        }
        functions = new ClassFunctions(TestFunctions.class, "test");

            vars.declareVariable("test", new TestFunctions(4, "test"));


            FunctionLibrary lib = new FunctionLibrary();
            lib.addFunctions(new ClassFunctions(TestFunctions.class, "test"));
            lib.addFunctions(new ClassFunctions(TestFunctions2.class, "test"));
            lib.addFunctions(new PackageFunctions("", "call"));
            lib.addFunctions(
                new PackageFunctions(
                    "org.apache.commons.jxpath.ri.compiler.",
                    "jxpathtest"));
            lib.addFunctions(new PackageFunctions("", null));
            context.setFunctions(lib);
        }
        functions = new ClassFunctions(TestFunctions.class, "test");
    }

Examples of org.apache.commons.jxpath.PackageFunctions

Related Classes of org.apache.commons.jxpath.PackageFunctions