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43 package org.netbeans.html.boot.spi;
45 import java.io.Closeable;
46 import java.io.IOException;
47 import java.io.InputStream;
48 import java.io.InputStreamReader;
49 import java.io.Reader;
51 import java.util.HashMap;
52 import java.util.HashSet;
55 import java.util.concurrent.Executor;
56 import net.java.html.js.JavaScriptBody;
57 import org.netbeans.html.boot.impl.FnContext;
59 /** Represents single JavaScript function that can be invoked.
60 * Created via {@link Presenter#defineFn(java.lang.String, java.lang.String...)}.
62 * @author Jaroslav Tulach
64 public abstract class Fn {
65 private final Presenter presenter;
68 * @deprecated Ineffective as of 0.6.
69 * Provide a presenter via {@link #Fn(org.netbeans.html.boot.spi.Fn.Presenter)}
77 /** Creates new function object and associates it with given presenter.
79 * @param presenter the browser presenter associated with this function
82 protected Fn(Presenter presenter) {
83 this.presenter = presenter;
86 /** True, if currently active presenter is the same as presenter this
87 * function has been created for via {@link #Fn(org.netbeans.html.boot.spi.Fn.Presenter)}.
89 * @return true, if proper presenter is used
91 public final boolean isValid() {
92 return presenter != null && FnContext.currentPresenter(false) == presenter;
95 /** Helper method to check if the provided instance is valid function.
96 * Checks if the parameter is non-null and if so, does {@link #isValid()}
99 * @param fnOrNull function or <code>null</code>
100 * @return true if the parameter is non-null and valid
103 public static boolean isValid(Fn fnOrNull) {
104 return fnOrNull != null && fnOrNull.isValid();
107 /** Helper method to find current presenter and ask it to define new
108 * function by calling {@link Presenter#defineFn(java.lang.String, java.lang.String...)}.
110 * @param caller the class who wishes to define the function
111 * @param code the body of the function (can reference <code>this</code> and <code>names</code> variables)
112 * @param names names of individual parameters
113 * @return the function object that can be {@link Fn#invoke(java.lang.Object, java.lang.Object...) invoked}
114 * - can return <code>null</code> if there is {@link #activePresenter() no presenter}
117 public static Fn define(Class<?> caller, String code, String... names) {
118 return define(caller, false, code, names);
121 /** Helper method to find current presenter and ask it to define new
124 * @param caller the class who wishes to define the function
125 * @param keepParametersAlive whether Java parameters should survive in JavaScript
126 * after the method invocation is over
127 * @param code the body of the function (can reference <code>this</code> and <code>names</code> variables)
128 * @param names names of individual parameters
129 * @return the function object that can be {@link Fn#invoke(java.lang.Object, java.lang.Object...) invoked}
130 * - can return <code>null</code> if there is {@link #activePresenter() no presenter}
133 public static Fn define(Class<?> caller, boolean keepParametersAlive, String code, String... names) {
134 final Presenter p = FnContext.currentPresenter(false);
138 if (p instanceof KeepAlive) {
140 if (!keepParametersAlive) {
141 arr = new boolean[names.length];
142 for (int i = 0; i < arr.length; i++) {
148 return ((KeepAlive)p).defineFn(code, names, arr);
150 return p.defineFn(code, names);
153 private static final Map<String,Set<Presenter>> LOADED = new HashMap<String, Set<Presenter>>();
155 /** Wraps function to ensure that the script represented by <code>resource</code>
156 * gets loaded into the browser environment before the function <code>fn</code>
159 * @param fn original function to call (if <code>null</code> returns <code>null</code>)
160 * @param caller the class who wishes to define/call the function
161 * @param resource resources (accessible via {@link ClassLoader#getResource(java.lang.String)})
162 * with a <em>JavaScript</em> that is supposed to loaded into the browser
164 * @return function that ensures the script is loaded and then delegates
165 * to <code>fn</code>. Returns <code>null</code> if the input <code>fn</code> is null
168 public static Fn preload(final Fn fn, final Class<?> caller, final String resource) {
172 return new Fn(fn.presenter()) {
174 public Object invoke(Object thiz, Object... args) throws Exception {
176 return fn.invoke(thiz, args);
180 public void invokeLater(Object thiz, Object... args) throws Exception {
182 fn.invokeLater(thiz, args);
185 private void loadResource() throws Exception {
186 Presenter p = presenter();
188 p = FnContext.currentPresenter(false);
191 Set<Presenter> there = LOADED.get(resource);
193 there = new HashSet<Presenter>();
194 LOADED.put(resource, there);
197 final ClassLoader l = caller.getClassLoader();
198 InputStream is = l.getResourceAsStream(resource);
199 if (is == null && resource.startsWith("/")) {
200 is = l.getResourceAsStream(resource.substring(1));
203 throw new IOException("Cannot find " + resource + " in " + l);
206 InputStreamReader r = new InputStreamReader(is, "UTF-8");
218 /** The currently active presenter.
220 * @return the currently active presenter or <code>null</code>
223 public static Presenter activePresenter() {
224 return FnContext.currentPresenter(false);
227 /** Activates given presenter. Used to associate the native
228 * JavaScript code specified by
229 * {@link JavaScriptBody} annotation with certain presenter:
231 * try ({@link Closeable} c = Fn.activate(presenter)) {
232 * doCallsInPresenterContext();
236 * @param p the presenter that should be active until closable is closed
237 * @return the closable to close
240 public static Closeable activate(Presenter p) {
241 return FnContext.activate(p);
244 /** Invokes the defined function with specified <code>this</code> and
245 * appropriate arguments.
247 * @param thiz the meaning of <code>this</code> inside of the JavaScript
248 * function - can be <code>null</code>
249 * @param args arguments for the function
250 * @return return value from the function
251 * @throws Exception if something goes wrong, as exception may be thrown
253 public abstract Object invoke(Object thiz, Object... args) throws Exception;
255 /** Invokes the defined function with specified <code>this</code> and
256 * appropriate arguments asynchronously. The invocation may be
257 * happen <em>"later"</em>.
259 * @param thiz the meaning of <code>this</code> inside of the JavaScript
260 * function - can be <code>null</code>
261 * @param args arguments for the function
262 * @throws Exception if something goes wrong, as exception may be thrown
265 public void invokeLater(Object thiz, Object... args) throws Exception {
269 /** Provides the function implementation access to the presenter provided
270 * in {@link #Fn(org.netbeans.html.boot.spi.Fn.Presenter) the constructor}.
272 * @return presenter passed in the constructor (may be, but should not be <code>null</code>)
275 protected final Presenter presenter() {
279 /** The representation of a <em>presenter</em> - usually a browser window.
280 * Should be provided by a library included in the application and registered
281 * in <code>META-INF/services</code>, for example with
282 * <code>@ServiceProvider(service = Fn.Presenter.class)</code> annotation.
284 * Since 0.7 a presenter may implement {@link Executor} interface, in case
285 * it supports single threaded execution environment. The executor's
286 * {@link Executor#execute(java.lang.Runnable)} method is then supposed
287 * to invoke the runnable immediately (in case we are on the right thread
288 * already) or return and asynchronously invoke the runnable later on the
289 * right thread (if we are on wrong thread).
291 public interface Presenter {
292 /** Creates new function with given parameter names and provided body.
294 * @param code the body of the function. Can refer to variables named
295 * as <code>names</code>
296 * @param names names of parameters of the function - these will be
297 * available when the <code>code</code> body executes
299 * @return function that can be later invoked
301 public Fn defineFn(String code, String... names);
303 /** Opens the browser, loads provided page and when the
304 * page is ready, it calls back to the provider runnable.
306 * @param page the URL for the page to display
307 * @param onPageLoad callback when the page is ready
309 public void displayPage(URL page, Runnable onPageLoad);
311 /** Loads a script into the browser JavaScript interpreter and
313 * @param code the script to execute
314 * @throws Exception if something goes wrong, throw an exception
316 public void loadScript(Reader code) throws Exception;
319 /** Additional interface to be implemented by {@link Presenter}s that
320 * wish to control what objects are passed into the JavaScript virtual
323 * If a JavaScript engine makes callback to Java method that returns
324 * a value, the {@link #toJavaScript(java.lang.Object)} method is
325 * consulted to convert the Java value to something reasonable inside
328 * <em>Note:</em> The implementation based on <em>JavaFX</em> <code>WebView</code>
329 * uses this interface to convert Java arrays to JavaScript ones.
334 public interface ToJavaScript {
335 /** Convert a Java return value into some object suitable for
336 * JavaScript virtual machine.
338 * @param toReturn the Java object to be returned
339 * @return the replacement value to return instead
341 public Object toJavaScript(Object toReturn);
344 /** Additional interface to be implemented by {@link Presenter}s that
345 * need to convert JavaScript object (usually array) to Java object
346 * when calling back from JavaScript to Java.
348 * <em>Note:</em> The implementation based on <em>JavaFX</em>
349 * <code>WebView</code> uses this interface to convert JavaScript arrays to
354 public interface FromJavaScript {
355 /** Convert a JavaScript object into suitable Java representation
356 * before a Java method is called with this object as an argument.
358 * @param js the JavaScript object
359 * @return replacement object for
361 public Object toJava(Object js);
364 /** Additional interface to {@link Presenter} to control more precisely
365 * garbage collection behavior of individual parameters. See
366 * {@link JavaScriptBody#keepAlive()} attribute for description of the
367 * actual behavior of the interface.
371 public interface KeepAlive {
372 /** Creates new function with given parameter names and provided body.
374 * @param code the body of the function. Can refer to variables named
375 * as <code>names</code>
376 * @param names names of parameters of the function - these will be
377 * available when the <code>code</code> body executes
378 * @param keepAlive array of booleans describing for each parameter
379 * whether it should be kept alive or not. Length of the array
380 * must be the same as length of <code>names</code> array. The
381 * array may be <code>null</code> to signal that all parameters
382 * should be <em>kept alive</em>.
384 * @return function that can be later invoked
386 public Fn defineFn(String code, String[] names, boolean[] keepAlive);