Note that as an exception, classes from the java package need not be qualified hence, we can write println(Object) instead of the valid, but longer, println(). The string to be passed provides a signature that Oracle Nashorn uses at resolution time. The second call uses a JavaScript object property to access the println(Object) variant. In the following code, the first call to println will select the println(String) overloaded method. This need mainly occurs with ambiguous parameters when you are passing a function object in which different interface types are permitted by overloaded methods, such as with the submit methods of executors. Still, there is a way to precisely select the required target if you need to. This means that you should never have to worry about overloaded methods when dealing with Java APIs. ![]() Oracle Nashorn properly selects the most suitable target at runtime on a per-invocation basis. The java.io.PrintStream class is a good example, providing many print and println methods for objects, strings, arrays, and primitive types. Java allows method overloading, that is, the definition within a single class of several methods that have the same names but different signatures. The global JavaScript scope is not affected, making JavaImporter a much better alternative to importClass and importPackage. JavaImporter takes a variable number of arguments as Java packages, and the returned object can be used in a with statement whose scope includes the specified package imports. Var CollectionsAndFiles = new JavaImporter( This is very simple to do thanks to the new OpenJDK build infrastructure (for example, sh configure & make images on a Mac OS X operating system with the XCode command-line tools installed). ![]() You can also use a custom build of OpenJDK 8. The examples can be run using a recent JDK 8 early-access release. It shows the Java-to-JavaScript interoperability and how Java types can be implemented and extended from JavaScript, providing a seamless integration between the two languages. It covers using the standalone engine through the jjs command-line tool as well as using Oracle Nashorn as an embedded scripting engine inside Java applications. This article is an introduction to using Oracle Nashorn in several ways. It provides better compliance with the ECMA normalized JavaScript specification and better runtime performance through invokedynamic-bound call sites. Java SE 8 will instead ship with a new engine called Oracle Nashorn, which is based on JSR 292 and invokedynamic. not the most elegant way, but this works.Until Java SE 7, JDKs shipped with a JavaScript scripting engine based on Mozilla Rhino. ![]() I have an ugly workaround in place right now which is based on a global variable that counts the number of time the shinyjs::runjs arm of the if statement was executed if the button counter has a different value from this global variable, I allow shinyjs::runjs to be executed. I tried to look at the reactLog but my app is so complex that this ends up being a huge messy ball of connected nodes that can hardly be read. The problem is that the expression inside the observeEvent is fired at least twice although the button is clicked only once and the of the event expression (input$init) remains the same. However, I am in a bit of a quandary right now because I have a follow-up problem with the implementation of this code in my real app and because I can not share this app due to BI issues. Hi off, your suggested code works just fine as is. Shinyjs::runjs("document.getElementById('downloadData').click() ") library(shiny)ĪctionButton("init", "Download", icon = icon("download")),ÄownloadButton("downloadData", "Download", style = "visibility: hidden ") However this isn't a perfect solution in terms of security because the actual download link will be visible in the html page source code. If your checks fail it will show the modal dialog, if they pass it will run some JS code using the shinyJS package to simulate a 'click' of the hidden download button and then the download handler code will run. Then I used an actionButton styled the same way as a download button to initiate an observeEvent block of code. ![]() The CSS styling hides the visibility of the actual downloadButton but it remains functional and accessible to client-side JS code. This was a bit tricky but I think I have a solution using some CSS and JS.
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