Replace usage of Xpath by pure java code walking through the DOM.

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@990619 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
jsdelfino 2010-08-29 18:30:47 +00:00
parent b095bb2e40
commit 6dea67b43e
3 changed files with 128 additions and 11 deletions

View file

@ -20,10 +20,14 @@
package sample;
import static java.lang.System.out;
import static sample.Xutil.dom;
import static sample.Xutil.elem;
import static sample.Xutil.elems;
import static sample.Xutil.print;
import static sample.Xutil.select;
import static sample.Xutil.text;
import static sample.Xutil.xpath;
import static sample.Xutil.xdom;
import static sample.Xutil.xfilter;
import static sample.Xutil.xreduce;
import org.w3c.dom.Element;
@ -52,8 +56,10 @@ public class ClientTest {
public String wello(String s) {
out.println("ClientTest.wello(" + s + ")");
final Element hreq = dom("http://sample", "hello", elem("name", text(s)));
final Element hreq = xdom("http://sample", "hello", elem("name", text(s)));
final Element hres = wello.call("hello", hreq);
return xpath("//*", hres);
return xreduce(print, "", xfilter(select("result"), elems(hres)));
}
}

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@ -20,10 +20,15 @@
package sample;
import static java.lang.System.out;
import static sample.Xutil.dom;
import static sample.Xutil.elem;
import static sample.Xutil.elems;
import static sample.Xutil.print;
import static sample.Xutil.select;
import static sample.Xutil.text;
import static sample.Xutil.xpath;
import static sample.Xutil.xdom;
import static sample.Xutil.xfilter;
import static sample.Xutil.xml;
import static sample.Xutil.xreduce;
import org.w3c.dom.Element;
@ -42,9 +47,13 @@ public class WelloTest {
WSDLReference upper;
public Element call(String op, Element e) {
out.println("WelloTest." + op + "(" + Xutil.xml(e) + ")");
final Element ureq = dom("http://sample", "upper", elem("s", text("Hello " + xpath("//name", e))));
out.println("WelloTest." + op + "(" + xml(e) + ")");
final String name = xreduce(print, "", xfilter(select("name"), elems(e)));
final Element ureq = xdom("http://sample", "upper", elem("s", text("Hello " + name)));
final Element ures = upper.call("upper", ureq);
return dom("http://sample", "helloResponse", elem("result", text(xpath("//*", ures))));
final String s = xreduce(print, "", xfilter(select("result"), elems(ures)));
return xdom("http://sample", "helloResponse", elem("result", text(s)));
}
}

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@ -20,6 +20,9 @@
package sample;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
@ -36,9 +39,10 @@ import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* A little bit of magic code and utility functions to help work with DOM.
* Just for fun, a little bit of magic code and utility functions to help work with XML DOM.
*/
class Xutil {
static class NodeBuilder {
@ -51,7 +55,7 @@ class Xutil {
/**
* Convert a name and a list of children to a document element.
*/
static Element dom(String ns, String name, final NodeBuilder... nodes) {
static Element xdom(String ns, String name, final NodeBuilder... nodes) {
return (Element)node(elem(ns, name, nodes), db.newDocument());
}
@ -139,4 +143,102 @@ class Xutil {
}
}
/**
* A pure Java FP-style alternative to xpath.
*/
interface Mapper<T> {
T map(final Element e);
}
static Mapper<Element> identity = new Mapper<Element>() {
public Element map(Element e) {
return e;
};
};
interface Reducer<T> {
T reduce(final T accum, final Element e);
}
static Reducer<String> print = new Reducer<String>() {
public String reduce(String accum, Element e) {
return accum + e.getTextContent();
}
};
/**
* Apply a mapper to a list of elements.
*/
static <T> List<T> xmap(final Mapper<T> f, final Iterable<Element> l) {
final List<T> v = new ArrayList<T>();
for(Element e: l)
v.add(f.map(e));
return v;
}
/**
* Apply a filter to a list of elements.
*/
static List<Element> xfilter(final Mapper<Boolean> f, final Iterable<Element> l) {
final List<Element> v = new ArrayList<Element>();
for(Element e: l)
if(f.map(e))
v.add(e);
return v;
}
/**
* Perform a reduction over a list of elements.
*/
static <T> T xreduce(final Reducer<T> f, final T initial, final Iterable<Element> l) {
T accum = initial;
for(Element e: l)
accum = f.reduce(accum, e);
return accum;
}
/**
* Return a filter that selects elements by name.
*/
static Mapper<Boolean> select(final String name) {
return new Mapper<Boolean>() {
public Boolean map(Element e) {
return name.equals(e.getLocalName());
}
};
}
/**
* Return the child elements of a node.
*/
static Iterable<Element> elems(final Node parent) {
final List<Element> l = new ArrayList<Element>();
for (Node n: children(parent))
if (n instanceof Element)
l.add((Element)n);
return l;
}
/**
* An iterable over the children of a node.
*/
private static Iterable<Node> children(Node parent) {
final NodeList l = parent.getChildNodes();
final int n = l.getLength();
return new Iterable<Node>() {
public Iterator<Node> iterator() {
return new Iterator<Node>() {
int i = 0;
public boolean hasNext() {
return i < n;
}
public Node next() {
return l.item(i++);
}
public void remove() {
}
};
}
};
}
}