Description
Evaluates the specified XPath expression and returns the result as a string.
License
Open Source License
Parameter
Parameter | Description |
---|
expression | The XPath expression to evaluate. |
node | The node to run the expression on. |
Exception
Parameter | Description |
---|
XPathExpressionException | If there was a problem processing the specified XPathexpression. |
Return
The string result.
Declaration
public static String asString(String expression, Node node)
throws XPathExpressionException
Method Source Code
//package com.java2s;
/*// w w w .j av a 2 s.c om
* Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
import javax.xml.xpath.XPathExpressionException;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class Main {
/**
* Evaluates the specified XPath expression and returns the result as a
* string.
*
* @param expression
* The XPath expression to evaluate.
* @param node
* The node to run the expression on.
*
* @return The string result.
*
* @throws XPathExpressionException
* If there was a problem processing the specified XPath
* expression.
*/
public static String asString(String expression, Node node)
throws XPathExpressionException {
return evaluateAsString(expression, node);
}
/**
* Evaluates the specified expression on the specified node and returns the
* result as a String.
*
* @param expression
* The Xpath expression to evaluate.
* @param node
* The node on which to evaluate the expression.
*
* @return The result of evaluating the specified expression, or null if the
* evaluation didn't return any result.
*
* @throws XPathExpressionException
* If there are any problems evaluating the Xpath expression.
*/
private static String evaluateAsString(String expression, Node node)
throws XPathExpressionException {
if (isEmpty(node))
return null;
String s = evaluateXPath(node, expression);
if (s == null) {
return null;
} else {
return s.trim();
}
}
/**
* Returns true if the specified node is null or has no children.
*
* @param node
* The node to test.
*
* @return True if the specified node is null or has no children.
*/
public static boolean isEmpty(Node node) {
return (node == null);
}
private static String evaluateXPath(Node node, String xPath) {
int currentSearchIndex = 0;
while (currentSearchIndex < xPath.length()) {
int endingIndex = xPath.indexOf("/", currentSearchIndex);
String noderNameFromXPath = null;
if (endingIndex == -1) {
noderNameFromXPath = xPath.substring(currentSearchIndex);
} else {
noderNameFromXPath = xPath.substring(currentSearchIndex,
endingIndex);
}
node = findChildNodeWithName(node, noderNameFromXPath);
if (endingIndex == -1) {
break;
}
currentSearchIndex = endingIndex + 1;
}
if (node != null && node.getFirstChild() != null) {
return node.getFirstChild().getNodeValue();
} else if (node != null) {
return node.getNodeValue();
} else {
return null;
}
}
private static Node findChildNodeWithName(Node node, String childName) {
if (node == null) {
return null;
} else {
if (node.getNodeName().equals(childName)) {
return node;
} else {
NodeList nodeList = node.getChildNodes();
for (int i = 0; i < nodeList.getLength(); i++) {
if (nodeList.item(i).getNodeName().equals(childName)) {
return nodeList.item(i);
}
}
return null;
}
}
}
}
Related
- asNode(String nodeName, Node node)
- asNodeList(String nodeName, Node node)
- asLong(String expression, Node node)
- asInteger(String expression, Node node)