Java tutorial
/* * Copyright 2012 Google Inc. * * 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.googlecode.gflot.client.jsni; import com.google.gwt.core.client.*; /** * Utility class for manipulating JS arrays. These methods are not on other * JavaScriptObject subclasses, such as JsArray, because adding new methods might * break existing subtypes. * FIXME delete this class if we move to GWT 2.5+ someday */ public class JsArrayUtils { /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayInteger readOnlyJsArray(byte[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayInteger dest = JsArrayInteger.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayNumber readOnlyJsArray(double[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayNumber dest = JsArrayNumber.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayNumber readOnlyJsArray(float[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayNumber dest = JsArrayNumber.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayInteger readOnlyJsArray(int[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayInteger dest = JsArrayInteger.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * <p> * <b>NOTE: long values are not supported in JS, so long emulation is slow * and this method assumes that all the values can be safely stored in a * double.</b> * * @param array source array - its values are assumed to be in the valid range * for doubles -- if the values exceed 2^53, low-order bits will be lost * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayNumber readOnlyJsArray(long[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayNumber dest = JsArrayNumber.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static JsArrayInteger readOnlyJsArray(short[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArrayInteger dest = JsArrayInteger.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * Take a Java array, and produce a JS array that is only used for reading. As * this is actually a reference to the original array in prod mode, the source * must not be modified while this copy is in use or you will get different * behavior between DevMode and prod mode. * * @param array source array * @return JS array, which may be a copy or an alias of the input array */ public static <T extends JavaScriptObject> JsArray<T> readOnlyJsArray(T[] array) { if (GWT.isScript()) { return arrayAsJsArrayForProdMode(array).cast(); } JsArray<T> dest = JavaScriptObject.createArray().cast(); for (int i = 0; i < array.length; ++i) { dest.push(array[i]); } return dest; } /** * In production mode, Java arrays really are JS arrays, so just return it. * * @param array must be a Java array of some type * @return a JavaScriptObject, which should be used as the appropriate type of * JS array depending on the input array type */ private static native JavaScriptObject arrayAsJsArrayForProdMode(Object array) /*-{ return array; }-*/; private JsArrayUtils() { } }