nl.colorize.util.xml.XPath.java Source code

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Here is the source code for nl.colorize.util.xml.XPath.java

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//-----------------------------------------------------------------------------
// Colorize Java Commons
// Copyright 2007-2019 Colorize
// Apache license (http://www.colorize.nl/code_license.txt)
//-----------------------------------------------------------------------------

package nl.colorize.util.xml;

import java.util.List;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.filter.Filters;
import org.jdom2.xpath.XPathExpression;
import org.jdom2.xpath.XPathFactory;

/**
 * XPath expression that can be used to query XML documents parsed with JDOM.
 * This class is a wrapper around JDOM's XPath API (that in turn uses jaxen 
 * internally).
 */
public class XPath {

    private XPathExpression<Element> expression;

    protected XPath(XPathExpression<Element> expression) {
        this.expression = expression;
    }

    /**
     * Queries an XML document using this XPath expression and returns the first
     * element found. If there are no results this will return {@code null}.
     */
    public Element findFirst(Document document) {
        return expression.evaluateFirst(document);
    }

    /**
     * Queries an XML document using this XPath expression and returns a list
     * containing all found elements.
     */
    public List<Element> findAll(Document document) {
        return expression.evaluate(document);
    }

    /**
     * Queries an XML document using this XPath expression and returns the text
     * content of the first element found. If there are no results this will 
     * return {@code null}.
     */
    public String findText(Document document) {
        Element result = findFirst(document);
        if (result != null) {
            return result.getText();
        } else {
            return null;
        }
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof XPath) {
            return toString().equals(o.toString());
        }
        return false;
    }

    @Override
    public int hashCode() {
        return toString().hashCode();
    }

    @Override
    public String toString() {
        return expression.toString();
    }

    /**
     * Creates an {@code XPath} instance from an XPath expression in text form.
     * @throws IllegalArgumentException if the expression is not valid XPath.
     */
    public static XPath parse(String expression) {
        XPathFactory xpathFactory = XPathFactory.instance();
        XPathExpression<Element> compiled = xpathFactory.compile(expression, Filters.element());
        return new XPath(compiled);
    }
}