Java example source code file (PasswordView.java)
The PasswordView.java Java example source code
/*
* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package javax.swing.text;
import sun.swing.SwingUtilities2;
import java.awt.*;
import javax.swing.JPasswordField;
/**
* Implements a View suitable for use in JPasswordField
* UI implementations. This is basically a field ui that
* renders its contents as the echo character specified
* in the associated component (if it can narrow the
* component to a JPasswordField).
*
* @author Timothy Prinzing
* @see View
*/
public class PasswordView extends FieldView {
/**
* Constructs a new view wrapped on an element.
*
* @param elem the element
*/
public PasswordView(Element elem) {
super(elem);
}
/**
* Renders the given range in the model as normal unselected
* text. This sets the foreground color and echos the characters
* using the value returned by getEchoChar().
*
* @param g the graphics context
* @param x the starting X coordinate >= 0
* @param y the starting Y coordinate >= 0
* @param p0 the starting offset in the model >= 0
* @param p1 the ending offset in the model >= p0
* @return the X location of the end of the range >= 0
* @exception BadLocationException if p0 or p1 are out of range
*/
protected int drawUnselectedText(Graphics g, int x, int y,
int p0, int p1) throws BadLocationException {
Container c = getContainer();
if (c instanceof JPasswordField) {
JPasswordField f = (JPasswordField) c;
if (! f.echoCharIsSet()) {
return super.drawUnselectedText(g, x, y, p0, p1);
}
if (f.isEnabled()) {
g.setColor(f.getForeground());
}
else {
g.setColor(f.getDisabledTextColor());
}
char echoChar = f.getEchoChar();
int n = p1 - p0;
for (int i = 0; i < n; i++) {
x = drawEchoCharacter(g, x, y, echoChar);
}
}
return x;
}
/**
* Renders the given range in the model as selected text. This
* is implemented to render the text in the color specified in
* the hosting component. It assumes the highlighter will render
* the selected background. Uses the result of getEchoChar() to
* display the characters.
*
* @param g the graphics context
* @param x the starting X coordinate >= 0
* @param y the starting Y coordinate >= 0
* @param p0 the starting offset in the model >= 0
* @param p1 the ending offset in the model >= p0
* @return the X location of the end of the range >= 0
* @exception BadLocationException if p0 or p1 are out of range
*/
protected int drawSelectedText(Graphics g, int x,
int y, int p0, int p1) throws BadLocationException {
g.setColor(selected);
Container c = getContainer();
if (c instanceof JPasswordField) {
JPasswordField f = (JPasswordField) c;
if (! f.echoCharIsSet()) {
return super.drawSelectedText(g, x, y, p0, p1);
}
char echoChar = f.getEchoChar();
int n = p1 - p0;
for (int i = 0; i < n; i++) {
x = drawEchoCharacter(g, x, y, echoChar);
}
}
return x;
}
/**
* Renders the echo character, or whatever graphic should be used
* to display the password characters. The color in the Graphics
* object is set to the appropriate foreground color for selected
* or unselected text.
*
* @param g the graphics context
* @param x the starting X coordinate >= 0
* @param y the starting Y coordinate >= 0
* @param c the echo character
* @return the updated X position >= 0
*/
protected int drawEchoCharacter(Graphics g, int x, int y, char c) {
ONE[0] = c;
SwingUtilities2.drawChars(Utilities.getJComponent(this),
g, ONE, 0, 1, x, y);
return x + g.getFontMetrics().charWidth(c);
}
/**
* Provides a mapping from the document model coordinate space
* to the coordinate space of the view mapped to it.
*
* @param pos the position to convert >= 0
* @param a the allocated region to render into
* @return the bounding box of the given position
* @exception BadLocationException if the given position does not
* represent a valid location in the associated document
* @see View#modelToView
*/
public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
Container c = getContainer();
if (c instanceof JPasswordField) {
JPasswordField f = (JPasswordField) c;
if (! f.echoCharIsSet()) {
return super.modelToView(pos, a, b);
}
char echoChar = f.getEchoChar();
FontMetrics m = f.getFontMetrics(f.getFont());
Rectangle alloc = adjustAllocation(a).getBounds();
int dx = (pos - getStartOffset()) * m.charWidth(echoChar);
alloc.x += dx;
alloc.width = 1;
return alloc;
}
return null;
}
/**
* Provides a mapping from the view coordinate space to the logical
* coordinate space of the model.
*
* @param fx the X coordinate >= 0.0f
* @param fy the Y coordinate >= 0.0f
* @param a the allocated region to render into
* @return the location within the model that best represents the
* given point in the view
* @see View#viewToModel
*/
public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) {
bias[0] = Position.Bias.Forward;
int n = 0;
Container c = getContainer();
if (c instanceof JPasswordField) {
JPasswordField f = (JPasswordField) c;
if (! f.echoCharIsSet()) {
return super.viewToModel(fx, fy, a, bias);
}
char echoChar = f.getEchoChar();
int charWidth = f.getFontMetrics(f.getFont()).charWidth(echoChar);
a = adjustAllocation(a);
Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a :
a.getBounds();
n = (charWidth > 0 ?
((int)fx - alloc.x) / charWidth : Integer.MAX_VALUE);
if (n < 0) {
n = 0;
}
else if (n > (getStartOffset() + getDocument().getLength())) {
n = getDocument().getLength() - getStartOffset();
}
}
return getStartOffset() + n;
}
/**
* Determines the preferred span for this view along an
* axis.
*
* @param axis may be either View.X_AXIS or View.Y_AXIS
* @return the span the view would like to be rendered into >= 0.
* Typically the view is told to render into the span
* that is returned, although there is no guarantee.
* The parent may choose to resize or break the view.
*/
public float getPreferredSpan(int axis) {
switch (axis) {
case View.X_AXIS:
Container c = getContainer();
if (c instanceof JPasswordField) {
JPasswordField f = (JPasswordField) c;
if (f.echoCharIsSet()) {
char echoChar = f.getEchoChar();
FontMetrics m = f.getFontMetrics(f.getFont());
Document doc = getDocument();
return m.charWidth(echoChar) * getDocument().getLength();
}
}
}
return super.getPreferredSpan(axis);
}
static char[] ONE = new char[1];
}
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