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Diffstat (limited to 'trunk/infrastructure/rhino1_7R1/examples/File.java')
| -rw-r--r-- | trunk/infrastructure/rhino1_7R1/examples/File.java | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/trunk/infrastructure/rhino1_7R1/examples/File.java b/trunk/infrastructure/rhino1_7R1/examples/File.java new file mode 100644 index 0000000..62bd980 --- /dev/null +++ b/trunk/infrastructure/rhino1_7R1/examples/File.java @@ -0,0 +1,348 @@ +/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (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.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Rhino code, released + * May 6, 1998. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1997-2000 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Norris Boyd + * + * Alternatively, the contents of this file may be used under the terms of + * the GNU General Public License Version 2 or later (the "GPL"), in which + * case the provisions of the GPL are applicable instead of those above. If + * you wish to allow use of your version of this file only under the terms of + * the GPL and not to allow others to use your version of this file under the + * MPL, indicate your decision by deleting the provisions above and replacing + * them with the notice and other provisions required by the GPL. If you do + * not delete the provisions above, a recipient may use your version of this + * file under either the MPL or the GPL. + * + * ***** END LICENSE BLOCK ***** */ + +import org.mozilla.javascript.*; +import java.io.*; +import java.util.Vector; + +/** + * Define a simple JavaScript File object. + * + * This isn't intended to be any sort of definitive attempt at a + * standard File object for JavaScript, but instead is an example + * of a more involved definition of a host object. + * + * Example of use of the File object: + * <pre> + * js> defineClass("File") + * js> file = new File("myfile.txt"); + * [object File] + * js> file.writeLine("one"); <i>only now is file actually opened</i> + * js> file.writeLine("two"); + * js> file.writeLine("thr", "ee"); + * js> file.close(); <i>must close file before we can reopen for reading</i> + * js> var a = file.readLines(); <i>creates and fills an array with the contents of the file</i> + * js> a; + * one,two,three + * js> + * </pre> + * + * + * File errors or end-of-file signaled by thrown Java exceptions will + * be wrapped as JavaScript exceptions when called from JavaScript, + * and may be caught within JavaScript. + * + * @author Norris Boyd + */ +public class File extends ScriptableObject { + + /** + * The zero-parameter constructor. + * + * When Context.defineClass is called with this class, it will + * construct File.prototype using this constructor. + */ + public File() { + } + + /** + * The Java method defining the JavaScript File constructor. + * + * If the constructor has one or more arguments, and the + * first argument is not undefined, the argument is converted + * to a string as used as the filename.<p> + * + * Otherwise System.in or System.out is assumed as appropriate + * to the use. + */ + public static Scriptable jsConstructor(Context cx, Object[] args, + Function ctorObj, + boolean inNewExpr) + { + File result = new File(); + if (args.length == 0 || args[0] == Context.getUndefinedValue()) { + result.name = ""; + result.file = null; + } else { + result.name = Context.toString(args[0]); + result.file = new java.io.File(result.name); + } + return result; + } + + /** + * Returns the name of this JavaScript class, "File". + */ + public String getClassName() { + return "File"; + } + + /** + * Get the name of the file. + * + * Used to define the "name" property. + */ + public String jsGet_name() { + return name; + } + + /** + * Read the remaining lines in the file and return them in an array. + * + * Implements a JavaScript function.<p> + * + * This is a good example of creating a new array and setting + * elements in that array. + * + * @exception IOException if an error occurred while accessing the file + * associated with this object + */ + public Object jsFunction_readLines() + throws IOException + { + Vector v = new Vector(); + String s; + while ((s = jsFunction_readLine()) != null) { + v.addElement(s); + } + Object[] lines = new Object[v.size()]; + v.copyInto(lines); + + Scriptable scope = ScriptableObject.getTopLevelScope(this); + Context cx = Context.getCurrentContext(); + return cx.newObject(scope, "Array", lines); + } + + /** + * Read a line. + * + * Implements a JavaScript function. + * @exception IOException if an error occurred while accessing the file + * associated with this object, or EOFException if the object + * reached the end of the file + */ + public String jsFunction_readLine() throws IOException { + return getReader().readLine(); + } + + /** + * Read a character. + * + * @exception IOException if an error occurred while accessing the file + * associated with this object, or EOFException if the object + * reached the end of the file + */ + public String jsFunction_readChar() throws IOException { + int i = getReader().read(); + if (i == -1) + return null; + char[] charArray = { (char) i }; + return new String(charArray); + } + + /** + * Write strings. + * + * Implements a JavaScript function. <p> + * + * This function takes a variable number of arguments, converts + * each argument to a string, and writes that string to the file. + * @exception IOException if an error occurred while accessing the file + * associated with this object + */ + public static void jsFunction_write(Context cx, Scriptable thisObj, + Object[] args, Function funObj) + throws IOException + { + write0(thisObj, args, false); + } + + /** + * Write strings and a newline. + * + * Implements a JavaScript function. + * @exception IOException if an error occurred while accessing the file + * associated with this object + * + */ + public static void jsFunction_writeLine(Context cx, Scriptable thisObj, + Object[] args, Function funObj) + throws IOException + { + write0(thisObj, args, true); + } + + public int jsGet_lineNumber() + throws FileNotFoundException + { + return getReader().getLineNumber(); + } + + /** + * Close the file. It may be reopened. + * + * Implements a JavaScript function. + * @exception IOException if an error occurred while accessing the file + * associated with this object + */ + public void jsFunction_close() throws IOException { + if (reader != null) { + reader.close(); + reader = null; + } else if (writer != null) { + writer.close(); + writer = null; + } + } + + /** + * Finalizer. + * + * Close the file when this object is collected. + */ + protected void finalize() { + try { + jsFunction_close(); + } + catch (IOException e) { + } + } + + /** + * Get the Java reader. + */ + public Object jsFunction_getReader() { + if (reader == null) + return null; + // Here we use toObject() to "wrap" the BufferedReader object + // in a Scriptable object so that it can be manipulated by + // JavaScript. + Scriptable parent = ScriptableObject.getTopLevelScope(this); + return Context.javaToJS(reader, parent); + } + + /** + * Get the Java writer. + * + * @see File#jsFunction_getReader + * + */ + public Object jsFunction_getWriter() { + if (writer == null) + return null; + Scriptable parent = ScriptableObject.getTopLevelScope(this); + return Context.javaToJS(writer, parent); + } + + /** + * Get the reader, checking that we're not already writing this file. + */ + private LineNumberReader getReader() throws FileNotFoundException { + if (writer != null) { + throw Context.reportRuntimeError("already writing file \"" + + name + + "\""); + } + if (reader == null) + reader = new LineNumberReader(file == null + ? new InputStreamReader(System.in) + : new FileReader(file)); + return reader; + } + + /** + * Perform the guts of write and writeLine. + * + * Since the two functions differ only in whether they write a + * newline character, move the code into a common subroutine. + * + */ + private static void write0(Scriptable thisObj, Object[] args, boolean eol) + throws IOException + { + File thisFile = checkInstance(thisObj); + if (thisFile.reader != null) { + throw Context.reportRuntimeError("already writing file \"" + + thisFile.name + + "\""); + } + if (thisFile.writer == null) + thisFile.writer = new BufferedWriter( + thisFile.file == null ? new OutputStreamWriter(System.out) + : new FileWriter(thisFile.file)); + for (int i=0; i < args.length; i++) { + String s = Context.toString(args[i]); + thisFile.writer.write(s, 0, s.length()); + } + if (eol) + thisFile.writer.newLine(); + } + + /** + * Perform the instanceof check and return the downcasted File object. + * + * This is necessary since methods may reside in the File.prototype + * object and scripts can dynamically alter prototype chains. For example: + * <pre> + * js> defineClass("File"); + * js> o = {}; + * [object Object] + * js> o.__proto__ = File.prototype; + * [object File] + * js> o.write("hi"); + * js: called on incompatible object + * </pre> + * The runtime will take care of such checks when non-static Java methods + * are defined as JavaScript functions. + */ + private static File checkInstance(Scriptable obj) { + if (obj == null || !(obj instanceof File)) { + throw Context.reportRuntimeError("called on incompatible object"); + } + return (File) obj; + } + + /** + * Some private data for this class. + */ + private String name; + private java.io.File file; // may be null, meaning to use System.out or .in + private LineNumberReader reader; + private BufferedWriter writer; +} + |