Example usage for org.apache.commons.jxpath BasicVariables BasicVariables

Introduction

In this page you can find the example usage for org.apache.commons.jxpath BasicVariables BasicVariables.

Prototype

BasicVariables

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Usage

From source file:org.paxml.core.Context.java

/**
 * Select objects with xpath./*from w  w w.j  a  va2  s  .  c o m*/
 * 
 * @param from
 *            the object to select properties from, null to select from
 *            entire context.
 * @param xpath
 *            the xpath
 * @param alwaysList
 *            true to return a list with one item inside if the xpath
 *            results in one object to be selected.
 * @return either a list of objects that satisfies the xpath, or the object
 *         itself if the xpath results in one object to be selected and the
 *         "alwaysList" parameter is false.
 */
public Object xpathSelect(Object from, String xpath, boolean alwaysList) {
    Variables vars = new BasicVariables();

    if (from == null) {
        ObjectTree nameGlobal = getRootContext().getNameMap(false, true);
        ObjectTree nameLocal = getNameMap(true, false);

        vars.declareVariable(XPATH_NAME_GLOBAL_VAR, nameGlobal);
        vars.declareVariable(XPATH_NAME_LOCAL_VAR, nameLocal);

        ObjectTree nameAuto = new ObjectTree(null, nameGlobal);
        nameAuto.addValues(nameLocal);

        from = nameAuto;
    }

    JXPathContext xpathContext = JXPathContext.newContext(from);
    xpathContext.setVariables(vars);
    xpathContext.setIdentityManager(this);

    setXpathFunctions(xpathContext);

    try {
        Object selected = xpathContext.iterate(xpath);

        List<Object> list = new ArrayList<Object>(1);
        if (selected instanceof Iterator) {
            final Iterator<?> it = (Iterator<?>) selected;
            while (it.hasNext()) {
                Object obj = it.next();
                list.add(getXpathResultObject(obj));
            }
            if (list.size() == 1) {
                selected = list.get(0);
            } else {
                selected = list;
            }
        } else {

            selected = getXpathResultObject(selected);

            if (selected != null && alwaysList) {
                list.add(selected);
            }
        }
        if (alwaysList) {
            return list;
        } else {
            if (selected instanceof List) {
                list = (List) selected;
                final int size = list.size();
                if (size == 0) {
                    return null;
                } else if (size == 1) {
                    return list.get(0);
                }
            }
            return selected;
        }
    } catch (NullPointerException e) {
        // when jxpath throws null pointer exception, it has problem
        // searching non-existing paths
        return null;
    }
}

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