Java tutorial
/* * Copyright 2011, The gwtquery team. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.cgxlib.xq.client.js; /* * #%L * CGXlib * %% * Copyright (C) 2016 CGXlib (http://www.cgxlib.com) * %% * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * #L% Code is originally from gwtquery, and modified by CGXlib team. */ import com.cgxlib.xq.client.Function; import com.cgxlib.xq.client.Properties; import com.cgxlib.xq.client.XQ; import com.google.gwt.core.client.*; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.Node; import com.google.gwt.dom.client.NodeList; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.DOM; import static com.cgxlib.xq.client.XQ.browser; /** * A bunch of utility methods for XQ. */ public class JsUtils { private static JsUtilsImpl utilsImpl = GWT.create(JsUtilsImpl.class); /** * Wraps a XQ function into a native javascript one so as we can * export Java methods without using JSNI. */ public static native JavaScriptObject wrapFunction(Function f) /*-{ return function (r) { var o = @java.util.ArrayList::new()(); for (i in arguments) { r = @com.cgxlib.xq.client.js.JsCache::gwtBox(*)([arguments[i]]); o.@java.util.ArrayList::add(Ljava/lang/Object;)(r); } o = o.@java.util.ArrayList::toArray()(); f.@com.cgxlib.xq.client.Function::setArguments([Ljava/lang/Object;)(o); return f.@com.cgxlib.xq.client.Function::fe([Ljava/lang/Object;)(o); } }-*/; /** * Returns a property present in a javascript object. */ public static <T> T prop(JavaScriptObject o, Object id, Class<? extends T> type) { return o == null ? null : o.<JsCache>cast().get(id, type); } /** * Returns a property present in a javascript object. */ public static <T> T prop(JavaScriptObject o, Object id) { return o == null ? null : o.<JsCache>cast().<T>get(id); } /** * Set a property to a javascript object. */ public static void prop(JavaScriptObject o, Object id, Object val) { if (o != null) { o.<JsCache>cast().put(id, val); } } /** * Assign a function to a property of the window object. */ public static void export(String name, Function f) { export(XQ.window, name, f); } /** * Export a function as a property of a javascript object. */ public static void export(JavaScriptObject o, String name, Function f) { prop(o, name, (Object) (f != null ? wrapFunction(f) : null)); } /** * Camelize style property names. * for instance: font-name -> fontName */ public static native String camelize(String s) /*-{ return s.replace(/\-(\w)/g, function (all, letter) { return letter.toUpperCase(); }); }-*/; /** * Merge the oldNodes list into the newNodes one. If oldNodes is null, a new * list will be created and returned. If oldNodes is not null, a new list will * be created depending on the create flag. */ public static NodeList<Element> copyNodeList(NodeList<Element> oldNodes, NodeList<Element> newNodes, boolean create) { NodeList<Element> ret = oldNodes == null || create ? JsNodeArray.create() : oldNodes; JsCache idlist = JsCache.create(); for (int i = 0; oldNodes != null && i < oldNodes.getLength(); i++) { Element e = oldNodes.getItem(i); idlist.put(e.hashCode(), 1); if (create) { ret.<JsNodeArray>cast().addNode(e, i); } } for (int i = 0, l = newNodes.getLength(), j = ret.getLength(); i < l; i++) { Element e = newNodes.getItem(i); if (!idlist.exists(e.hashCode())) { ret.<JsNodeArray>cast().addNode(newNodes.getItem(i), j++); } } return ret; } /** * Use the method in the xq class. * $(elem).cur(prop, force); */ @Deprecated public static double cur(Element elem, String prop, boolean force) { return XQ.$(elem).cur(prop, force); } /** * Compare two numbers using javascript equality. */ public static native boolean eq(double s1, double s2) /*-{ return s1 == s2; }-*/; /** * Compare two objects using javascript equality. */ public static native boolean eq(Object s1, Object s2) /*-{ return s1 == s2; }-*/; /** * Returns the owner document element of an element. */ public static Document getOwnerDocument(Node n) { return n == null || !isElement(n) ? null : n.getNodeType() == Node.DOCUMENT_NODE ? n.<Document>cast() : n.getOwnerDocument(); } /** * Check if an object has a property with <code>name</code> defined. * It supports dots in the name meaning checking nested properties. * <p/> * Example: * <pre> * // Check whether a browser supports touch events * hasProperty(window, "ontouchstart"); * </pre> */ public static native boolean hasProperty(JavaScriptObject o, String name)/*-{ var p = name.split('.'); for (var i in p) { if (!(o && p[i] in o)) return false; o = o[p[i]]; } return true; }-*/; /** * Check whether an element has an attribute, this is here since GWT Element.getAttribute * implementation returns an empty string instead of null when the attribute is not * present. */ public static native boolean hasAttribute(Element o, String name) /*-{ return !!(o && o.getAttribute(name)); }-*/; /** * Hyphenize style property names. * for instance: fontName -> font-name */ public static native String hyphenize(String name) /*-{ return name.replace(/([A-Z])/g, "-$1").toLowerCase(); }-*/; /** * Check is a javascript object can be used as an array. */ public static native boolean isArray(JavaScriptObject o) /*-{ return Object.prototype.toString.call(o) == '[object Array]' || typeof o.length == 'number'; }-*/; /** * Check is a javascript object is a FormData. */ public static native boolean isFormData(JavaScriptObject o) /*-{ return Object.prototype.toString.call(o) == '[object FormData]'; }-*/; /** * Return whether the event was prevented. */ public static native boolean isDefaultPrevented(JavaScriptObject e) /*-{ return e.defaultPrevented || e.returnValue === false || e.getPreventDefault && e.getPreventDefault() ? true : false; }-*/; /** * Return whether a node is detached to the DOM. * <p/> * Be careful : This method works only on node that should be inserted within the body node. */ public static boolean isDetached(Node n) { assert n != null; if ("html".equalsIgnoreCase(n.getNodeName())) { return false; } return !getOwnerDocument(n).getBody().isOrHasChild(n); } /** * Check is a javascript object can be cast to an Element. */ public static native boolean isElement(Object o) /*-{ return !!o && 'nodeType' in o && 'nodeName' in o; }-*/; /** * Check is a javascript object can be cast to an Event. */ public static boolean isEvent(JavaScriptObject o) { return hasProperty(o, "currentTarget"); } /** * Check is a javascript object is a function. */ public static native boolean isFunction(JavaScriptObject o) /*-{ return Object.prototype.toString.call(o) == '[object Function]'; }-*/; /** * Check is a javascript can be cast to a node list. */ public static native boolean isNodeList(JavaScriptObject o) /*-{ var r = Object.prototype.toString.call(o); return r == '[object HTMLCollection]' || r == '[object NodeList]' || (typeof o == 'object' && o.length && o[0].tagName) ? true : false; }-*/; /** * Check is a javascript object is a Window. */ public static boolean isWindow(JavaScriptObject o) { return hasProperty(o, "alert"); } /** * Check if an element is a DOM or a XML node. */ public static boolean isXML(Node o) { return o == null ? false : !"HTML".equals(getOwnerDocument(o).getDocumentElement().getNodeName()); } /** * Load an external javascript library. The inserted script replaces the * element with the given id in the document. * * @deprecated use {@link com.cgxlib.xq.client.plugins.ajax.Ajax#loadScript(String)} */ @Deprecated public static void loadScript(String url, String id) { XQ gs = XQ.$(DOM.createElement("script")); XQ gp = XQ.$("#" + id).parent(); if (gp.size() != 1) { gp = XQ.$(XQ.document.getBody()); } XQ.$("#" + id).remove(); gp.append(gs.attr("src", url).attr("type", "text/javascript").attr("id", id)); } /** * Return the element which is truth in the double scope. */ public static native double or(double s1, double s2) /*-{ return s1 || s2; }-*/; /** * Return the element which is truth in the javascript scope. */ public static native <T> T or(T s1, T s2) /*-{ return s1 || s2; }-*/; /** * Parses a json string returning a Object with useful method to get the * content. */ public static Properties parseJSON(String json) { try { return utilsImpl.parseJSON(json); } catch (Exception e) { if (!GWT.isProdMode()) { System.err.println("Error while parsing json: " + e.getMessage() + ".\n" + json); } return Properties.create(); } } /** * Parses a xml string and return the xml document element which can then be * passed to XQ to create a typical XQ object that can be traversed * and manipulated. */ public static Element parseXML(String xml) { return utilsImpl.parseXML(xml); } public static String text(Element e) { return utilsImpl.text(e); } /** * Utility method to cast objects in production. * Useful for casting native implementations to interfaces like JsInterop */ public static native <T> T cast(Object o) /*-{ return o; }-*/; /** * Utility method to cast objects to array of string in production. */ public static native String[] castArrayString(Object a) /*-{ return a }-*/; /** * Call any arbitrary function present in a Javascript object. * It checks the existence of the function and object hierarchy before executing it. * It's very useful in order to avoid writing jsni blocks for very simple snippets. * <p/> * Note that GWT 3.0 jsinterop will come with a method similar, so we might deprecate * this in the future. * <p/> * Example * <pre> * // Create a svg node in our document. * Element svg = jsni(document, "createElementNS", "http://www.w3.org/2000/svg", "svg"); * // Append it to the dom * $(svg).appendTo(document); * // show the svg element in the debug console * jsni("console.log", svg); * </pre> * * @param jso the object containing the method to execute * @param meth the literal name of the function to call, dot separators are allowed. * @param args an array with the arguments to pass to the function. * @return the java ready boxed object returned by the jsni method or null, if the * call return a number we will get a Double, if it returns a boolean we get a java * Boolean, strings comes as java String, otherwise we get the javascript object. */ public static <T> T jsni(JavaScriptObject jso, String meth, Object... args) { return runJavascriptFunction(jso, meth, args); } /** * Run any arbitrary function in javascript scope using the window as the base object. * It checks the existence of the function and object hierarchy before executing it. * It's very useful in order to avoid writing jsni blocks for very simple snippets. * <p/> * Note that GWT 3.0 jsinterop will come with a method similar, so we might deprecate * this in the future. * <p/> * Example * <pre> * // Create a svg node in our document. * Element svg = jsni("document.createElementNS", "http://www.w3.org/2000/svg", "svg"); * // Append it to the dom * $(svg).appendTo(document); * // show the svg element in the debug console * jsni("console.log", svg); * </pre> * * @param meth the literal name of the function to call, dot separators are allowed. * @param args an array with the arguments to pass to the function. * @return the java ready boxed object returned by the jsni method or null, if the * call return a number we will get a Double, if it returns a boolean we get a java * Boolean, strings comes as java String, otherwise we get the javascript object. */ public static <T> T jsni(String meth, Object... args) { return runJavascriptFunction(null, meth, args); } /** * Call via jsni any arbitrary function present in a Javascript object. * <p/> * It's thought for avoiding to create jsni methods to call external functions and * facilitate the writing of js wrappers. * <p/> * Example * <pre> * // Create a svg node in our document. * Element svg = runJavascriptFunction(document, "createElementNS", "http://www.w3.org/2000/svg", "svg"); * // Append it to the dom * $(svg).appendTo(document); * </pre> * * @param o the javascript object where the function is, it it is null we use window. * @param meth the literal name of the function to call, dot separators are allowed. * @param args an array with the arguments to pass to the function. * @return the java ready boxed object returned by the jsni method or null, if the * call return a number we will get a Double, if it returns a boolean we get a java * Boolean, strings comes as java String, otherwise we get the javascript object. * @deprecated use jsni instead. */ public static <T> T runJavascriptFunction(JavaScriptObject o, String meth, Object... args) { return runJavascriptFunctionImpl(o, meth, JsObjectArray.create().add(args).<JsArrayMixed>cast()); } private static native <T> T runJavascriptFunctionImpl(JavaScriptObject o, String meth, JsArrayMixed args) /*-{ var f = o || $wnd, p = meth.split('.'); for (var i in p) { o = f; f = f[p[i]]; if (!f) return null; } return @com.cgxlib.xq.client.js.JsUtils::isFunction(*)(f) && @com.cgxlib.xq.client.js.JsCache::gwtBox(*)([f.apply(o, args)]); }-*/; /** * Check if a number is true in the javascript scope. */ public static native boolean truth(double a) /*-{ return a ? true : false; }-*/; /** * Check if an object is true in the javascript scope. */ public static native boolean truth(Object a) /*-{ return a ? true : false; }-*/; /** * Remove duplicates from an elements array. */ public static JsArray<Element> unique(JsArray<Element> a) { return utilsImpl.unique(a); } public static String XML2String(JavaScriptObject js) { return utilsImpl.XML2String(js); } public static String JSON2String(JavaScriptObject js) { return utilsImpl.JSON2String(js); } /** * Returns a QueryString representation of a JavascriptObject. * <p/> * TODO: jquery implementation accepts a second parameter (traditional) */ public static String param(JavaScriptObject js) { Properties prop = js.cast(); String ret = ""; for (String k : prop.keys()) { ret += ret.isEmpty() ? "" : "&"; JsCache o = prop.getArray(k).cast(); if (o != null) { for (int i = 0, l = o.length(); i < l; i++) { ret += i > 0 ? "&" : ""; Properties p = o.<JsCache>cast().getJavaScriptObject(i); if (p != null) { ret += k + "[]=" + p.toJsonString(); } else { ret += k + "[]=" + o.getString(i); } } } else { Properties p = prop.getJavaScriptObject(k); if (p != null) { ret += k + "=" + p.tostring(); } else { String v = prop.getStr(k); if (v != null && !v.isEmpty() && !"null".equalsIgnoreCase(v)) { ret += k + "=" + v; } } } } return ret; } /** * A Function which wraps a javascript function. */ public static class JsFunction extends Function implements Command { private JavaScriptObject jso = null; public JsFunction(JavaScriptObject f) { if (JsUtils.isFunction(f)) { jso = f; } } public boolean equals(Object obj) { return jso.equals(obj); } public int hashCode() { return jso.hashCode(); } private native Object exec(JavaScriptObject f, Object data) /*-{ return @com.cgxlib.xq.client.js.JsCache::gwtBox(*)([f(data)]); }-*/; public void f() { if (jso != null) { setArguments(exec(jso, arguments(0))); } } public void execute() { f(); } } /** * Default JsUtils implementation. */ public static class JsUtilsImpl { public Properties parseJSON(String json) { return JsonUtils.safeEval(json); } public native String JSON2String(JavaScriptObject o) /*-{ return $wnd.JSON.stringify(o); }-*/; public native Element parseXML(String xml) /*-{ return new DOMParser().parseFromString(xml, "text/xml").documentElement; }-*/; public String text(Element e) { return e.getInnerText(); } public JsArray<Element> unique(JsArray<Element> a) { JsArray<Element> ret = JavaScriptObject.createArray().cast(); JsCache cache = JsCache.create(); for (int i = 0; i < a.length(); i++) { Element e = a.get(i); int id = e.hashCode(); if (!cache.exists(id)) { cache.putNumber(id, 1); ret.push(e); } } return ret; } public native String XML2String(JavaScriptObject o) /*-{ return (new XMLSerializer()).serializeToString(o); }-*/; } /** * IE JsUtils implemetation. */ public static class JsUtilsImplIE6 extends JsUtilsImpl { @Override public Properties parseJSON(String json) { return JsonUtils.unsafeEval(json); } @Override public String JSON2String(JavaScriptObject js) { // This is a very basic implementation for IE6/IE7 of JSON.stringify // If many people demand a better one we could consider to use json2.js // @see https://github.com/douglascrockford/JSON-js/blob/master/json2.js Properties prop = js.cast(); String ret = ""; for (String k : prop.keys()) { String ky = k.matches("\\d+") ? k : "\"" + k + "\""; JsCache o = prop.getArray(k).cast(); if (o != null) { ret += ky + ":["; for (int i = 0, l = o.length(); i < l; i++) { Properties p = o.<JsCache>cast().getJavaScriptObject(i); if (p != null) { ret += p.toJsonString() + ","; } else { ret += "\"" + o.getString(i) + "\","; } } ret += "],"; } else { Properties p = prop.getJavaScriptObject(k); if (p != null) { ret += ky + ":" + p.toJsonString() + ","; } else { ret += ky + ":\"" + prop.getStr(k) + "\","; } } } return "{" + ret.replaceAll(",\\s*([\\]}]|$)", "$1") .replaceAll("([:,\\[])\"(-?[\\d\\.]+|null|false|true)\"", "$1$2") + "}"; } @Override public native Element parseXML(String xml) /*-{ var d = new ActiveXObject("Microsoft.XmlDom"); d.loadXML(xml); return d.documentElement; }-*/; @Override public String text(Element e) { return isXML(e) ? xmlText(e) : super.text(e); } @Override public JsArray<Element> unique(JsArray<Element> a) { // in IE6 XML elements does not support adding hashId to the object if (browser.ie6 && isXML(a.get(0))) { return a; } return super.unique(a); } @Override public native String XML2String(JavaScriptObject o) /*-{ return o.xml; }-*/; private native String xmlText(Element e) /*-{ return e.text; }-*/; } }