com.gridsystems.nextgrid.api.pom.expr
Class XPathExpression

java.lang.Object
  nextgrid.api.pom.Expression
      com.gridsystems.nextgrid.api.pom.expr.XPathExpression

All Implemented Interfaces:

java.io.Serializable

public final class XPathExpression
extends nextgrid.api.pom.Expression

XPath expression wrapper to simplify expression handling.

XPath is focused on retrieving and selecting nodes from an XML document. In this case we use its ability in the following way:

• Jakarta Commons JXPath is used to use arbitrary Java objects as data sources, instead of plain XML files.
• We will consider that an XPath expression is equivalent to true if (and only if) it returns a minimum number of results, which is 1 by default.

Author:

Rodrigo Ruiz

See Also:

Serialized Form

Constructor Summary

XPathExpression(java.lang.String text)
Creates a new instance.

XPathExpression(java.lang.String text, int min, int max)
Creates a new instance.

Method Summary

boolean	boolEval(nextgrid.api.env.ProcessEnvironment env, java.lang.Object o)
org.apache.commons.jxpath.JXPathContext	getRootContext(nextgrid.api.env.ProcessEnvironment env) Gets a shared context instance for the specified Process Environment.
void	validate()

Methods inherited from class nextgrid.api.pom.Expression

getLang, getText

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XPathExpression

public XPathExpression(java.lang.String text)
                throws nextgrid.api.pom.ExpressionException

Creates a new instance.

Parameters:

text - The XPath expression

Throws:

nextgrid.api.pom.ExpressionException - If a compilation error occurs

XPathExpression

public XPathExpression(java.lang.String text,
                       int min,
                       int max)
                throws nextgrid.api.pom.ExpressionException

Creates a new instance.

Parameters:

text - The XPath expression

min - The minimum number of results

max - The maximum number of results

Throws:

nextgrid.api.pom.ExpressionException - If a compilation error occurs

Method Detail

validate

public void validate()
              throws nextgrid.api.pom.ExpressionException

Specified by:

validate in class nextgrid.api.pom.Expression

Throws:

nextgrid.api.pom.ExpressionException

boolEval

public boolean boolEval(nextgrid.api.env.ProcessEnvironment env,
                        java.lang.Object o)
                 throws nextgrid.api.pom.ExpressionException

Specified by:

boolEval in class nextgrid.api.pom.Expression

Throws:

nextgrid.api.pom.ExpressionException

getRootContext

public org.apache.commons.jxpath.JXPathContext getRootContext(nextgrid.api.env.ProcessEnvironment env)

Gets a shared context instance for the specified Process Environment.

This context will contain common variable definitions.

Parameters:

env - ProcessEnvironment for which to get a context

Returns:

The context