--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/samples/dynalink/DOMLinkerExporter.java Wed Dec 09 16:56:34 2015 +0530
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of Oracle nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.util.ArrayList;
+import java.util.List;
+import jdk.dynalink.CallSiteDescriptor;
+import jdk.dynalink.CompositeOperation;
+import jdk.dynalink.NamedOperation;
+import jdk.dynalink.Operation;
+import jdk.dynalink.StandardOperation;
+import jdk.dynalink.linker.GuardingDynamicLinker;
+import jdk.dynalink.linker.GuardingDynamicLinkerExporter;
+import jdk.dynalink.linker.GuardedInvocation;
+import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
+import jdk.dynalink.linker.LinkRequest;
+import jdk.dynalink.linker.LinkerServices;
+import jdk.dynalink.linker.support.Guards;
+import jdk.dynalink.linker.support.Lookup;
+import org.w3c.dom.Attr;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+import org.w3c.dom.Element;
+
+/**
+ * This is a dynalink pluggable linker (see http://openjdk.java.net/jeps/276).
+ * This linker handles XML DOM Element objects specially. This linker links
+ * special properties starting with "_" and treats those as child element names
+ * to access. This kind of child element access makes it easy to write XML DOM
+ * accessing scripts. See for example ./dom_linker_gutenberg.js.
+ */
+public final class DOMLinkerExporter extends GuardingDynamicLinkerExporter {
+ static {
+ System.out.println("pluggable dynalink DOM linker loaded");
+ }
+
+ // return List of child Elements of the given Element matching the given name.
+ private static List<Element> getChildElements(Element elem, String name) {
+ NodeList nodeList = elem.getChildNodes();
+ List<Element> childElems = new ArrayList<>();
+ int len = nodeList.getLength();
+ for (int i = 0; i < len; i++) {
+ Node node = nodeList.item(i);
+ if (node.getNodeType() == Node.ELEMENT_NODE &&
+ ((Element)node).getTagName().equals(name)) {
+ childElems.add((Element)node);
+ }
+ }
+ return childElems;
+ }
+
+ // method that returns either unique child element matching given name
+ // or a list of child elements of that name (if there are more than one matches).
+ public static Object getElementsByName(Object elem, final String name) {
+ List<Element> elems = getChildElements((Element)elem, name);
+ return elems.size() == 1? elems.get(0) : elems;
+ }
+
+ // method to extract text context under a given DOM Element
+ public static Object getElementText(Object elem) {
+ NodeList nodeList = ((Element)elem).getChildNodes();
+ int len = nodeList.getLength();
+ StringBuilder text = new StringBuilder();
+ for (int i = 0; i < len; i++) {
+ Node node = nodeList.item(i);
+ if (node.getNodeType() == Node.TEXT_NODE) {
+ text.append(node.getNodeValue());
+ }
+ }
+ return text.toString();
+ }
+
+ private static final MethodHandle ELEMENTS_BY_NAME;
+ private static final MethodHandle ELEMENT_TEXT;
+ private static final MethodHandle IS_ELEMENT;
+ static {
+ ELEMENTS_BY_NAME = Lookup.PUBLIC.findStatic(DOMLinkerExporter.class,
+ "getElementsByName",
+ MethodType.methodType(Object.class, Object.class, String.class));
+ ELEMENT_TEXT = Lookup.PUBLIC.findStatic(DOMLinkerExporter.class,
+ "getElementText",
+ MethodType.methodType(Object.class, Object.class));
+ IS_ELEMENT = Guards.isInstance(Element.class, MethodType.methodType(Boolean.TYPE, Object.class));
+ }
+
+ @Override
+ public List<GuardingDynamicLinker> get() {
+ final ArrayList<GuardingDynamicLinker> linkers = new ArrayList<>();
+ linkers.add(new TypeBasedGuardingDynamicLinker() {
+ @Override
+ public boolean canLinkType(final Class<?> type) {
+ return Element.class.isAssignableFrom(type);
+ }
+
+ @Override
+ public GuardedInvocation getGuardedInvocation(LinkRequest request,
+ LinkerServices linkerServices) throws Exception {
+ final Object self = request.getReceiver();
+ if (! (self instanceof Element)) {
+ return null;
+ }
+
+ CallSiteDescriptor desc = request.getCallSiteDescriptor();
+ Operation op = desc.getOperation();
+ Object name = NamedOperation.getName(op);
+ boolean getProp = CompositeOperation.contains(
+ NamedOperation.getBaseOperation(op),
+ StandardOperation.GET_PROPERTY);
+ if (getProp && name instanceof String) {
+ String nameStr = (String)name;
+
+ // Treat names starting with "_" as special names.
+ // Everything else is linked other dynalink bean linker!
+ // This avoids collision with Java methods of org.w3c.dom.Element class
+ // Assumption is that Java APIs won't start with "_" character!!
+ if (nameStr.equals("_")) {
+ // short-hand to get text content under a given DOM Element
+ return new GuardedInvocation(ELEMENT_TEXT, IS_ELEMENT);
+ } else if (nameStr.startsWith("_")) {
+ return new GuardedInvocation(
+ MethodHandles.insertArguments(ELEMENTS_BY_NAME, 1, nameStr.substring(1)),
+ IS_ELEMENT);
+ }
+
+ }
+
+ return null;
+ }
+ });
+ return linkers;
+ }
+}