diff -r 44779bfb4c13 -r 412a690d4414 nashorn/samples/dynalink/DOMLinkerExporter.java --- /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 getChildElements(Element elem, String name) { + NodeList nodeList = elem.getChildNodes(); + List 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 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 get() { + final ArrayList 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; + } +}