import java.lang.*; import java.awt.*; import java.applet.*; /* * Purpose: The main program of the applet */ public class ControlStructure extends Applet { Image img, img2; ControlPanel ControlWin; TextArea CodeWinEdit, CodeWinDisplay; Panel InputWin; ImageScrollPanel ScrolledDiagramWin; public void init() { img = createImage(1500, 1500); setLayout(new BorderLayout()); Panel Contain = new Panel(); ScrolledDiagramWin = new ImageScrollPanel(img, 1300, 1300); ScrolledDiagramWin.reshape(0, 0, 550, 300); /* * input code textarea (Editable) */ CodeWinEdit = new TextArea("while (x > 0) {\n" + " x++;\n" + " printf(\"x : %d\\n\");\n" + " do x--; while (x > 0);\n" + " if (x>0)\n" + " x=1;\n" + " else\n" + " x=0;\n" + "}\n"); CodeWinEdit.resize(225, 200); CodeWinEdit.setBackground(Color.gray); CodeWinEdit.setEditable(true); Panel panel1 = new Panel(); panel1.setLayout(new BorderLayout()); panel1.add("North", new Label("Input Code (Editable)", Label.CENTER)); panel1.add("Center", CodeWinEdit); /* * simplified code textarea (Non-editable) */ CodeWinDisplay = new TextArea("", 15, 10); CodeWinDisplay.resize(225, 200); CodeWinDisplay.setBackground(Color.gray); CodeWinDisplay.setEditable(false); Panel panel2 = new Panel(); panel2.setLayout(new BorderLayout()); panel2.add("North", new Label("Simplified Code (Non-editable)", Label.CENTER)); panel2.add("Center", CodeWinDisplay); Panel CodeWin = new Panel(); CodeWin.setLayout(new GridLayout(1, 2)); CodeWin.add(panel1); CodeWin.add(panel2); ControlWin = new ControlPanel(CodeWinEdit, CodeWinDisplay, ScrolledDiagramWin); ScrolledDiagramWin.setControlPanel(ControlWin); add("North", ControlWin); add("Center", ScrolledDiagramWin); add("South", CodeWin); } } /* End Class ControlStructure */ /* * Purpose: the control panel */ class ControlPanel extends Panel { TextArea t, d; ImageScrollPanel fd; public Button ConvertButton, ClearButton, RunButton; public ProgramObj program=null; public ControlPanel(TextArea input, TextArea dpy, ImageScrollPanel FlowDiagram) { t = input; d = dpy; fd = FlowDiagram; setLayout(new FlowLayout(FlowLayout.LEFT)); ConvertButton = new Button("Convert !"); ClearButton = new Button("Clear"); RunButton = new Button(" Run "); add(ConvertButton); add(ClearButton); add(RunButton); RunButton.disable(); } public boolean action(Event e, Object arg) { if (e.target instanceof Button) { String str = ((Button)(e.target)).getLabel(); if (str.equals("Convert !")) { StringBuffer s = new StringBuffer(); Parse Parsing = new Parse(t.getText()); program = Parsing.go(); if (program == null) { System.err.println("Error: convert empty program!"); } else if (Parsing.ErrStatus) { MsgDialog ErrMsg = new MsgDialog("Error", Parsing.ErrStr); ErrMsg.show(); } else { fd.clear(); fd.ImgGc.setColor(Color.black); program.draw(70, 50, fd.ImgGc); fd.redraw(); program.print(s, 0); String string = s.toString(); d.setText(string); RunButton.enable(); } } else if (str.equals("Clear")) { t.setText(""); d.setText(""); fd.clear(); fd.redraw(); RunButton.disable(); } else if (str.equals(" Run ")) { RunFlowChart Run = new RunFlowChart(fd, d, program, this); Thread t = new Thread(Run); t.start(); ConvertButton.disable(); ClearButton.disable(); RunButton.disable(); } } return true; } } /* End Class ControlPanel */ /* * Purpose: the scrolling drawing area containing the flowchart */ class ImageScrollPanel extends ScrollPanel { private Image img; public Graphics ImgGc; public int width, height; ControlPanel cp; public ImageScrollPanel(Image i, int w, int h) { super(i, w, h); img = i; ImgGc = img.getGraphics(); width = w; height = h; clear(); } public void setControlPanel(ControlPanel p) { cp = p; } public boolean mouseDown(Event e, int x, int y) { if (cp.program == null) return true; int posx = x+horiz.getValue(); int posy = y+vert.getValue(); cp.program.CheckInside(posx, posy); return true; } public void clear() { ImgGc.setColor(Color.white); ImgGc.fillRect(0, 0, width, height); } public void redraw() { super.setImage(img, width, height); } } /* End Class ImageScrollPanel */ /* * Purpose: Dialog showing the content of condition and statements */ class ShowContentDialog extends Frame { Button bokay; TextArea ta; String text, head; public ShowContentDialog() { super(); setBackground(Color.white); setForeground(Color.black); setLayout(new BorderLayout()); bokay = new Button("OK"); Panel panel = new Panel(); panel.add(bokay); add("Center", ta = new TextArea("")); add("South", panel); resize(300, 200); ta.setEditable(false); } public void setHeading(String str) { setTitle(str); } public void setText(String str) { ta.setText(str); } /* public void paint(Graphics g) { super.paint(g); FontMetrics fm = g.getFontMetrics(); g.drawString(text, (250-fm.stringWidth(text))/2, 80); } */ public boolean action(Event e, Object arg) { if (e.target instanceof Button) { hide(); } return true; } } /* End Class ShowContentDialog */ /* * Purpose: Message Dialog */ class MsgDialog extends Frame { Button bokay; String text; public MsgDialog(String heading, String msg) { super(heading); setText(msg); setBackground(Color.gray); setForeground(Color.white); setLayout(new BorderLayout()); bokay = new Button("OK"); Panel panel = new Panel(); panel.add(bokay); add("South", panel); resize(250, 150); } public void setText(String str) { text = new String(str); } public void paint(Graphics g) { super.paint(g); FontMetrics fm = g.getFontMetrics(); g.drawString(text, (250-fm.stringWidth(text))/2, 80); } public boolean action(Event e, Object arg) { if (e.target instanceof Button) { hide(); } return true; } } /* End Class MsgDialog */ /* * Purpose: Dialog to ask the user the truth value of a condition */ class ConditionDialog extends Frame { Button btrue, bfalse; RunFlowChart run; String text; public ConditionDialog(RunFlowChart r) { super("Runing the Program"); run = r; setBackground(Color.gray); setForeground(Color.white); setLayout(new BorderLayout()); btrue = new Button("True"); bfalse = new Button("False"); Panel panel = new Panel(); panel.add(btrue); panel.add(bfalse); add("South", panel); resize(250, 150); } public void setText(String str) { text = new String(str); } public void paint(Graphics g) { super.paint(g); FontMetrics fm = g.getFontMetrics(); g.drawString(text, (250-fm.stringWidth(text))/2, 80); } public boolean action(Event e, Object arg) { if (e.target instanceof Button) { String str = ((Button)(e.target)).getLabel(); hide(); if (str == "True") run.ConditionValue = true; else run.ConditionValue = false; run.t.resume(); } return true; } } /* End Class ConditionDialog */ /* * Purpose: Dialog to ask the user to continue the execution of the flow * chart program */ class NextDialog extends Frame { Button bnext; RunFlowChart run; String text; public NextDialog(RunFlowChart r) { super("Runing the Program"); run = r; setBackground(Color.gray); setForeground(Color.white); setLayout(new BorderLayout()); bnext = new Button("Next"); Panel panel = new Panel(); panel.add(bnext); add("South", panel); resize(250, 150); } public void setText(String str) { text = new String(str); } public void paint(Graphics g) { super.paint(g); FontMetrics fm = g.getFontMetrics(); g.drawString(text, (250-fm.stringWidth(text))/2, 100-fm.getHeight()); g.drawString("Press next to continue", (250-fm.stringWidth("Press next to continue"))/2, 100); } public boolean action(Event e, Object arg) { if (e.target instanceof Button) { hide(); run.t.resume(); } return true; } } /* End Class NextDialog */ /* * Purpose: A simple dialog displaying a text string and a okay button */ class OkayDialog extends Frame { Button bokay; RunFlowChart run; String text; public OkayDialog(RunFlowChart r) { super("Runing the Program"); run = r; setBackground(Color.gray); setForeground(Color.white); setLayout(new BorderLayout()); bokay = new Button("OK"); Panel panel = new Panel(); panel.add(bokay); add("South", panel); resize(250, 150); } public void setText(String str) { text = new String(str); } public void paint(Graphics g) { super.paint(g); FontMetrics fm = g.getFontMetrics(); g.drawString(text, (250-fm.stringWidth(text))/2, 80); } public boolean action(Event e, Object arg) { if (e.target instanceof Button) { hide(); run.t.resume(); } return true; } } /* End Class OkayDialog */ /* * Purpose: running the program in the flow chart */ class RunFlowChart implements Runnable { ProgramObj program; ImageScrollPanel flowchart; ControlPanel control; ConditionDialog conditionD; NextDialog nextD; OkayDialog okayD; public Thread t; public boolean ConditionValue = false; TextArea dpy; public RunFlowChart(ImageScrollPanel fc, TextArea d, ProgramObj p, ControlPanel cp) { program = p; flowchart = fc; control = cp; dpy = d; conditionD = new ConditionDialog(this); nextD = new NextDialog(this); okayD = new OkayDialog(this); } public void run() { go(program); } void redraw() { flowchart.clear(); flowchart.ImgGc.setColor(Color.black); program.draw(70, 50, flowchart.ImgGc); flowchart.redraw(); } void go(ControlObj obj) { if (obj == null) return; if (obj instanceof ProgramObj) { obj.active = true; ((ProgramObj)obj).begin = true; redraw(); t = Thread.currentThread(); nextD.setText("The beginning of the program"); nextD.show(); t.suspend(); obj.active = false; go(((ProgramObj)obj).content); obj.active = true; ((ProgramObj)obj).begin = false; redraw(); t = Thread.currentThread(); dpy.select(0, 0); okayD.setText("The end of the program"); okayD.show(); t.suspend(); obj.active = false; control.ConvertButton.enable(); control.ClearButton.enable(); control.RunButton.enable(); } else if (obj instanceof StmtList) { go(((StmtList)obj).CodeSeg); go(((StmtList)obj).next); } else if (obj instanceof StatementObj) { obj.active = true; redraw(); t = Thread.currentThread(); dpy.select(obj.SelectStart, obj.SelectEnd); nextD.setText("Now Statements "+((StatementObj)obj).StatementNo+" is executing...."); nextD.show(); t.suspend(); obj.active = false; } else if (obj instanceof IfObj) { obj.active = true; redraw(); t = Thread.currentThread(); dpy.select(obj.SelectStart, obj.SelectEnd); conditionD.setText("The truth value of Condition "+((IfObj)obj).ConditionNo+"?"); conditionD.show(); t.suspend(); obj.active = false; if (ConditionValue == true) go(((IfObj)obj).yes); else go(((IfObj)obj).no); } else if (obj instanceof WhileObj) { while (true) { obj.active = true; redraw(); t = Thread.currentThread(); dpy.select(obj.SelectStart, obj.SelectEnd); conditionD.setText("The truth value of Condition "+((WhileObj)obj).ConditionNo+"?"); conditionD.show(); t.suspend(); obj.active = false; if (ConditionValue == true) go(((WhileObj)obj).content); else break; } } else if (obj instanceof RepeatObj) { do { obj.active = false; go(((RepeatObj)obj).content); obj.active = true; redraw(); t = Thread.currentThread(); dpy.select(obj.SelectStart, obj.SelectEnd); conditionD.setText("The truth value of Condition "+((RepeatObj)obj).ConditionNo+"?"); conditionD.show(); t.suspend(); obj.active = false; } while (ConditionValue == true); } } /* End Method go */ } /* End Class RunFlowChart */ /************************************************************************ The following classes are the internal representation of the user inputed program or flowchart. ************************************************************************/ class ControlType { static int IF=0; static int WHILE=1; static int REPEAT=2; static int STATEMENT=3; static int STMTLIST=4; static int PROGRAM=5; } class UnitInfo { Dimension unitsize; int up, bottom; public UnitInfo(int w, int h, int u, int b) { unitsize = new Dimension(w, h); up = u; bottom = b; } public UnitInfo() { this(0,0,0,0); } } /* * This is the base class of all the nodes in the internal representation of * the flowcharts. There are four main methods need to implement when * subclassing it: * * size() - return the size of this particular instance of the class needed * in the flow diagram * draw() - draw this instance of the class on the flow diagram * print() - print the simplified code * CheckInside() [optoinal] - if this class has a condition box or statement * box drawn on the flow diagram, this method check * whether a point is inside the box */ abstract class ControlObj { int type; Dimension boxsize = new Dimension(90, 40); static int hseparation = 20; static int vseparation = 40; boolean active = false; int SelectStart=1, SelectEnd=2; public abstract UnitInfo size(); public abstract void draw(int x, int y, Graphics g); public abstract void print(StringBuffer sb, int indentation); public abstract boolean CheckInside(int x, int y); public Polygon recordCondition(int x, int y) { int xarray[] = new int[5]; int yarray[] = new int[5]; xarray[0] = x; xarray[1] = x+boxsize.width/2; xarray[2] = x+boxsize.width; xarray[3] = x+boxsize.width/2; xarray[4] = x; yarray[0] = y+boxsize.height/2; yarray[1] = y; yarray[2] = y+boxsize.height/2; yarray[3] = y+boxsize.height; yarray[4] = y+boxsize.height/2; Polygon p = new Polygon(xarray, yarray, 5); return p; } /* End Method recordCondition() */ public void drawCondition(int x, int y, int no, Graphics g) { int xarray[] = new int[5]; int yarray[] = new int[5]; xarray[0] = x; xarray[1] = x+boxsize.width/2; xarray[2] = x+boxsize.width; xarray[3] = x+boxsize.width/2; xarray[4] = x; yarray[0] = y+boxsize.height/2; yarray[1] = y; yarray[2] = y+boxsize.height/2; yarray[3] = y+boxsize.height; yarray[4] = y+boxsize.height/2; Polygon p = new Polygon(xarray, yarray, 5); if (active) { g.setColor(Color.yellow); g.fillPolygon(p); g.setColor(Color.black); } g.drawPolygon(p); /* g.drawLine(x, y+boxsize.height/2, x+boxsize.width/2, y); g.drawLine(x+boxsize.width/2, y, x+boxsize.width, y+boxsize.height/2); g.drawLine(x+boxsize.width, y+boxsize.height/2, x+boxsize.width/2, y+boxsize.height); g.drawLine(x+boxsize.width/2, y+boxsize.height, x, y+boxsize.height/2); */ g.setColor(Color.red); g.drawString("Condition "+Integer.toString(no), x+10, y+25); g.setColor(Color.black); } public void drawDownArrowLine(int x1, int y1, int x2, int y2, Graphics g) { int maxy = Math.max(y1, y2); int miny = Math.min(y1, y2); g.drawLine(x1, y1, x2, y2); g.drawLine(x1, miny+(maxy-miny)/2, x1-5, miny+(maxy-miny)/2-5); g.drawLine(x1, miny+(maxy-miny)/2, x1+5, miny+(maxy-miny)/2-5); } public void drawUpArrowLine(int x1, int y1, int x2, int y2, Graphics g) { int maxy = Math.max(y1, y2); int miny = Math.min(y1, y2); g.drawLine(x1, y1, x2, y2); g.drawLine(x1, miny+(maxy-miny)/2, x1-5, miny+(maxy-miny)/2+5); g.drawLine(x1, miny+(maxy-miny)/2, x1+5, miny+(maxy-miny)/2+5); } public void drawLeftArrowLine(int x1, int y1, int x2, int y2, Graphics g) { int maxx = Math.max(x1, x2); int minx = Math.min(x1, x2); g.drawLine(x1, y1, x2, y2); g.drawLine(minx+(maxx-minx)/2, y1, minx+(maxx-minx)/2+5, y1-5); g.drawLine(minx+(maxx-minx)/2, y1, minx+(maxx-minx)/2+5, y1+5); } public void drawRightArrowLine(int x1, int y1, int x2, int y2, Graphics g) { int maxx = Math.max(x1, x2); int minx = Math.min(x1, x2); g.drawLine(x1, y1, x2, y2); g.drawLine(minx+(maxx-minx)/2, y1, minx+(maxx-minx)/2-5, y1-5); g.drawLine(minx+(maxx-minx)/2, y1, minx+(maxx-minx)/2-5, y1+5); } } /* End Class ControlObj */ class StmtList extends ControlObj { ControlObj CodeSeg; StmtList next; public StmtList() { type = ControlType.STMTLIST; } public UnitInfo size() { UnitInfo tmp = new UnitInfo(0,0,0,0); UnitInfo u1 = CodeSeg.size(); if (next == null) return u1; UnitInfo u2 = next.size(); int lup1 = u1.up; int rup1 = u1.unitsize.width - u1.up; int lbottom1 = u1.bottom; int rbottom1 = u1.unitsize.width - u1.bottom; int lup2 = u2.up; int rup2 = u2.unitsize.width - u2.up; int lbottom2 = u2.bottom; int rbottom2 = u2.unitsize.width - u2.bottom; tmp.unitsize.height = u1.unitsize.height + u2.unitsize.height; tmp.unitsize.width = u1.unitsize.width + u2.unitsize.width - Math.min(lbottom1, lup2) - Math.min(rbottom1, rup2); if (lbottom1 > lup2) { tmp.up = u1.up; tmp.bottom = (lbottom1-lup2) + lbottom2; } else { tmp.up = (lup2-lbottom1) + lup1; tmp.bottom = lbottom2; } return tmp; } /* End of size() */ public boolean CheckInside(int x, int y) { if (CodeSeg.CheckInside(x, y) == false) return false; if (next != null) return next.CheckInside(x, y); return true; } public void draw(int x, int y, Graphics g) { UnitInfo u1 = CodeSeg.size(); if (next == null) { CodeSeg.draw(x, y, g); } else { UnitInfo u2 = next.size(); if (u1.bottom > u2.up) { CodeSeg.draw(x, y, g); next.draw(x+(u1.bottom-u2.up), y+u1.unitsize.height, g); } else { CodeSeg.draw(x+(u2.up-u1.bottom), y, g); next.draw(x, y+u1.unitsize.height, g); } } } /* End of draw(int, int, Graphics) */ public void print(StringBuffer sb, int indentation) { CodeSeg.print(sb, indentation); if (next != null) next.print(sb, indentation); } } /* End Class StmtList */ class StatementObj extends ControlObj { int StatementNo; String StatementContent; int posx=-1, posy=-1; ShowContentDialog dialog = new ShowContentDialog(); public StatementObj() { type = ControlType.STATEMENT; } public UnitInfo size() { UnitInfo tmp = new UnitInfo(boxsize.width, boxsize.height+vseparation, boxsize.width/2, boxsize.width/2); return tmp; } public boolean CheckInside(int x, int y) { if (x < 0) return true; if ( (x >= posx && x <= posx+boxsize.width) && (y >= posy && y <= posy+boxsize.height) ) { /* System.out.println(StatementContent); */ dialog.setTitle("Content of Statements "+StatementNo); dialog.setText(StatementContent); dialog.show(); return false; } else return true; } public void draw(int x, int y, Graphics g) { if (active) { g.setColor(Color.yellow); g.fillRect(x, y, boxsize.width, boxsize.height); g.setColor(Color.black); } posx = x; posy = y; g.drawRect(x, y, boxsize.width, boxsize.height); drawDownArrowLine(x+boxsize.width/2, y+boxsize.height, x+boxsize.width/2, y+boxsize.height+vseparation, g); /* FontMetrics fm = g.getFontMetrics(); g.drawString("Statements", x+(boxsize.width-fm.stringWidth("Statements"))/2, y+(boxsize.height+fm.getHeight())/2); */ g.setColor(Color.red); g.drawString("Statements "+Integer.toString(StatementNo), x+10, y+25); g.setColor(Color.black); } public void print(StringBuffer sb, int indentation) { SelectStart = sb.length()+indentation; SelectEnd = SelectStart+("Statments "+StatementNo).length(); for (int i=0; i nosize.unitsize.height) { g.drawLine(x+yessize.unitsize.width+2*hseparation+nosize.bottom, y+boxsize.height/2+vseparation+nosize.unitsize.height, x+yessize.unitsize.width+2*hseparation+nosize.bottom, y+boxsize.height/2+vseparation+yessize.unitsize.height); } else { g.drawLine(x+yessize.bottom, y+boxsize.height/2+vseparation+yessize.unitsize.height, x+yessize.bottom, y+boxsize.height/2+vseparation+nosize.unitsize.height); } } else { g.drawLine(x+yessize.unitsize.width+hseparation+boxsize.width/2, y+boxsize.height/2, x+yessize.unitsize.width+2*hseparation+boxsize.width/2, y+boxsize.height/2); drawDownArrowLine(x+yessize.unitsize.width+2*hseparation+boxsize.width/2, y+boxsize.height/2, x+yessize.unitsize.width+2*hseparation+boxsize.width/2, y+boxsize.height/2+vseparation+yessize.unitsize.height, g); } drawDownArrowLine(x+yessize.unitsize.width+hseparation, y+boxsize.height/2+vseparation+Math.max(yessize.unitsize.height, nosize.unitsize.height), x+yessize.unitsize.width+hseparation, y+boxsize.height/2+vseparation+Math.max(yessize.unitsize.height, nosize. unitsize.height)+vseparation, g); g.drawLine(x+yessize.bottom, y+boxsize.height/2+vseparation+Math.max(yessize.unitsize.height, nosize.unitsize.height), x+yessize.unitsize.width+2*hseparation+nosize.bottom, y+boxsize.height/2+vseparation+Math.max(yessize.unitsize.height, nosize.unitsize.height)); } public void print(StringBuffer sb, int indentation) { int indent; SelectStart = sb.length()+indentation+4; SelectEnd = SelectStart+("Condition "+ConditionNo).length(); if (indentation < 0) { indent = -1*indentation; } else { indent = indentation; for (int i=0; i