/******************************************************************************* * * * File: Applet_04.java Revision: 1.0 * * * * Contents: controlling a browser from within an applet * * * * Creation: 08.07.1996 Last Modification: 17.04.2002 * * * * Platform: IBM-compatible PC running Windows 98SE * * * * Environment: Java 1.4 * * * * Author: Andreas Rozek Phone: ++49 (711) 6770682 * * Kirschblütenweg 15 Fax: - * * D-70569 Stuttgart EMail: Andreas.Rozek@T-Online.De * * Germany * * * * URL: http://www.Andreas-Rozek.de/ * * * * Copyright: this software is published under the "GNU General Public Li- * * cense" (see "http://www.gnu.org/copyleft/gpl.html" for addi- * * tional information) * * * * Comments: meanwhile, the original source code (for Java 1.0.2) has been * * updated in order to compile under Java 1.1.8 and Java 1.4 w/o * * major problems * * * *******************************************************************************/ import java.applet.*; // basic applet classes import java.awt.*; // basic AWT classes (& interfaces) import java.io.*; // Java file handling and stream IO import java.net.*; // Java network support import java.util.*; // Java utility classes and data structures public class Applet_04 extends java.applet.Applet { /**** information about author, version and copyright of this applet ****/ final static String AppletInfo = "Applet_04 - controlling a browser from within an applet\n" + "\n" + "Andreas Rozek\n" + "Kirschblütenweg 15\n" + "D-70569 Stuttgart\n" + "Germany\n" + "\n" + "Phone: ++49 (711) 6770682\n" + "Fax: -\n" + "EMail: Andreas.Rozek@T-Online.De\n" + "URL: http://www.Andreas-Rozek.de"; /**** information about foreseen applet parameters ****/ final static String[][] ParameterInfo = null; /**** desired applet insets ****/ final static Insets AppletInsets = new Insets(0,4,4,4); /**** user interface components ****/ Button ShowButton; // initiates the display of a new web page Checkbox SelfBox, ParentBox, TopBox, BlankBox, NameBox; CheckboxGroup TargetGroup; /******************************************************************************* * * * getAppletInfo provides information about author, version and copyright * * * *******************************************************************************/ public String getAppletInfo () { return AppletInfo; // see above for definition of "AppletInfo" }; /******************************************************************************* * * * getInsets returns actual applet insets * * * *******************************************************************************/ public final Insets getInsets () { return AppletInsets; }; /******************************************************************************* * * * getParameterInfo provides information about foreseen applet parameters * * * *******************************************************************************/ public String[][] getParameterInfo () { return ParameterInfo; // see above for definition of "ParameterInfo" }; /******************************************************************************* * * * handleEvent main applet event handler * * * *******************************************************************************/ public synchronized boolean handleEvent (Event AWTEvent) { if ((AWTEvent.id == Event.ACTION_EVENT) && (AWTEvent.target == ShowButton)) { Checkbox TargetBox = TargetGroup.getSelectedCheckbox(); if (TargetBox == SelfBox) { getAppletContext().showDocument(URL_of("self.html"), "_self"); return true; }; if (TargetBox == ParentBox) { getAppletContext().showDocument(URL_of("parent.html"), "_parent"); return true; }; if (TargetBox == TopBox) { getAppletContext().showDocument(URL_of("top.html"), "_top"); return true; }; if (TargetBox == BlankBox) { getAppletContext().showDocument(URL_of("blank.html"), "_blank"); return true; }; if (TargetBox == NameBox) { getAppletContext().showDocument(URL_of("named.html"), "separate Top-Level window"); return true; }; }; /**** let somebody else handle this event ****/ return super.handleEvent(AWTEvent); // applets don't seem to have a "processEvent" }; /******************************************************************************* * * * init initialize an applet each time it's loaded or reloaded * * * *******************************************************************************/ public void init () { Label TextLabel; // temporarily stores a text label /**** unify the visual appearance of an applet on different platforms ****/ setBackground(Color.lightGray); setFont(new Font("Helvetica", Font.PLAIN, 11)); /**** prepare user interface ****/ setLayout(new GridBagLayout()); TargetGroup = new CheckboxGroup(); TextLabel = new Label("Applet_04 - controlling a browser"); TextLabel.setFont(new Font("Helvetica", Font.BOLD, 12)); add_GridItem(TextLabel, 0,0, 2,1, fill_x, 0,0, 1,2,0,0, align_w, 0,0); add_GridItem(new ColorBox(0,2, Color.black), 0,1, 2,1, fill_x, 0,0, 0,0,4,0, align_w, 0,0); TextLabel = new Label("display a new web page"); add_GridItem(TextLabel, 0,2, 1,1, fill_x, 0,0, 0,2,0,0, align_w, 0,0); ShowButton = new Button("Show"); add_GridItem(ShowButton, 1,2, 1,1, fill_x, 0,0, 0,2,0,0, align_w, 0,0); SelfBox = new Checkbox("in the current frame", TargetGroup, true); add_GridItem(SelfBox, 0,3, 2,1, fill_x, 0,0, 0,8,0,0, align_w, 0,0); ParentBox = new Checkbox("in the parent frame", TargetGroup, false); add_GridItem(ParentBox, 0,4, 2,1, fill_x, 0,0, 0,8,0,0, align_w, 0,0); TopBox = new Checkbox("in the top-most frame", TargetGroup, false); add_GridItem(TopBox, 0,5, 2,1, fill_x, 0,0, 0,8,0,0, align_w, 0,0); BlankBox = new Checkbox("in a new unnamed top-level window", TargetGroup, false); add_GridItem(BlankBox, 0,6, 2,1, fill_x, 0,0, 0,8,0,0, align_w, 0,0); NameBox = new Checkbox("in a new named top-level window", TargetGroup, false); add_GridItem(NameBox, 0,7, 2,1, fill_x, 0,0, 0,8,0,0, align_w, 0,0); TextLabel = new Label(""); add_GridItem(TextLabel, 0,8, 1,1, fill_both, 0,0, 0,2,0,0, align_w, 9,9); /**** resize and show applet ****/ // resize(preferredSize()); setVisible(true); }; /******************************************************************************* * * * paint (re)draws applet contents * * * *******************************************************************************/ public void paint (Graphics Graf) { int Width = getSize().width-1; // "cache" applet dimensions int Height = getSize().height-1; /**** draw border with "3D" effect ****/ Graf.setColor(Color.white); Graf.drawLine(0,0, Width-1,0); Graf.drawLine(0,0, 0,Height); Graf.setColor(Color.gray); Graf.drawLine(Width,0, Width,Height); Graf.drawLine(1,Height, Width,Height); }; /******************************************************************************* * * * URL_of constructs an URL for a test document * * * *******************************************************************************/ public final URL URL_of (String DocName) { try { return new URL(getDocumentBase(), DocName); } catch (MalformedURLException Signal) { /* empty */ }; return getDocumentBase(); }; /******************************************************************************* * * * Assisting Fields and Methods * * * *******************************************************************************/ /**** local equivalents of "GridBagConstraints" constants ****/ final static int align_c = GridBagConstraints.CENTER; final static int align_n = GridBagConstraints.NORTH; final static int align_ne = GridBagConstraints.NORTHEAST; final static int align_e = GridBagConstraints.EAST; final static int align_se = GridBagConstraints.SOUTHEAST; final static int align_s = GridBagConstraints.SOUTH; final static int align_sw = GridBagConstraints.SOUTHWEST; final static int align_w = GridBagConstraints.WEST; final static int align_nw = GridBagConstraints.NORTHWEST; final static int fill_none = GridBagConstraints.NONE; final static int fill_x = GridBagConstraints.HORIZONTAL; final static int fill_y = GridBagConstraints.VERTICAL; final static int fill_both = GridBagConstraints.BOTH; /******************************************************************************* * * * add_GridItem adds a "Component" to a "GridBag" using the given constraints * * * *******************************************************************************/ void add_GridItem ( Component Item, // the item to be added to the grid int GridX, // leftmost column to be occupied by a grid element int GridY, // topmost row to be occupied by a grid element int GridWidth, // number of columns to be occupied by a grid element int GridHeight, // number of rows to be occupied by a grid element int Fill, // in which direction should a grid element be expanded? int IPadX, // internal horizontal padding int IPadY, // internal vertical padding int InsetTop, // top margin between cell and grid element int InsetLeft, // left margin between cell and grid element int InsetBottom, // bottom margin between cell and grid element int InsetRight, // right margin between cell and grid element int Anchor, // grid element alignment inside a cell int WeightX, // element "priority" for gaining extra horizontal space int WeightY // element "priority" for gaining extra vertical space ) { if (Item == null) return; /**** create a new "GridBagConstraints" object... ****/ GridBagConstraints Constraints = new GridBagConstraints(); /**** fill in the given arguments... ****/ Constraints.gridx = GridX; Constraints.gridy = GridY; Constraints.gridwidth = GridWidth; Constraints.gridheight = GridHeight; Constraints.fill = Fill; Constraints.ipadx = IPadX; Constraints.ipady = IPadY; Constraints.insets = new Insets(InsetTop, InsetLeft, InsetBottom, InsetRight); Constraints.anchor = Anchor; Constraints.weightx = Math.max(0,Math.min(99,WeightX)) * 100.0; Constraints.weighty = Math.max(0,Math.min(99,WeightY)) * 100.0; /**** then add "Item" using the given constraints ****/ add(Item); ((GridBagLayout) getLayout()).setConstraints(Item,Constraints); }; }; /******************************************************************************* * * * ColorBox * * * *******************************************************************************/ class ColorBox extends Canvas { int Width, Height; // desired dimensions public ColorBox (int LineWidth, int LineHeight, Color LineColor) { super(); // just to be complete Width = Math.max(0,LineWidth); Height = Math.max(0,LineHeight); setBackground(LineColor); }; public Dimension getMinimumSize () { return new Dimension((Width == 0 ? 1 : Width),(Height == 0 ? 1 : Height)); }; public Dimension getPreferredSize () { return new Dimension((Width == 0 ? Math.max(getSize().width, 1) : Width), (Height == 0 ? Math.max(getSize().height,1) : Height)); }; };