/* * Copyright (c) 1998, 2004, 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 * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing.text.html; import java.util.Enumeration; import java.awt.*; import javax.swing.*; import javax.swing.text.*; import java.beans.*; import java.lang.reflect.*; /** * Component decorator that implements the view interface * for <object> elements. *
* This view will try to load the class specified by the
* classid
attribute. If possible, the Classloader
* used to load the associated Document is used.
* This would typically be the same as the ClassLoader
* used to load the EditorKit. If the document's
* ClassLoader is null, Class.forName
is used.
*
* If the class can successfully be loaded, an attempt will
* be made to create an instance of it by calling
* Class.newInstance
. An attempt will be made
* to narrow the instance to type java.awt.Component
* to display the object.
*
* This view can also manage a set of parameters with limitations. * The parameters to the <object> element are expected to * be present on the associated elements attribute set as simple * strings. Each bean property will be queried as a key on * the AttributeSet, with the expectation that a non-null value * (of type String) will be present if there was a parameter * specification for the property. Reflection is used to * set the parameter. Currently, this is limited to a very * simple single parameter of type String. *
* A simple example HTML invocation is: *
* <object classid="javax.swing.JLabel"> * <param name="text" value="sample text"> * </object> ** * @author Timothy Prinzing */ public class ObjectView extends ComponentView { /** * Creates a new ObjectView object. * * @param elem the element to decorate */ public ObjectView(Element elem) { super(elem); } /** * Create the component. The classid is used * as a specification of the classname, which * we try to load. */ protected Component createComponent() { AttributeSet attr = getElement().getAttributes(); String classname = (String) attr.getAttribute(HTML.Attribute.CLASSID); try { Class c = Class.forName(classname, true,Thread.currentThread(). getContextClassLoader()); Object o = c.newInstance(); if (o instanceof Component) { Component comp = (Component) o; setParameters(comp, attr); return comp; } } catch (Throwable e) { // couldn't create a component... fall through to the // couldn't load representation. } return getUnloadableRepresentation(); } /** * Fetch a component that can be used to represent the * object if it can't be created. */ Component getUnloadableRepresentation() { // PENDING(prinz) get some artwork and return something // interesting here. Component comp = new JLabel("??"); comp.setForeground(Color.red); return comp; } /** * Get a Class object to use for loading the * classid. If possible, the Classloader * used to load the associated Document is used. * This would typically be the same as the ClassLoader * used to load the EditorKit. If the documents * ClassLoader is null, *
Class.forName
is used.
*/
private Class getClass(String classname) throws ClassNotFoundException {
Class klass;
Class docClass = getDocument().getClass();
ClassLoader loader = docClass.getClassLoader();
if (loader != null) {
klass = loader.loadClass(classname);
} else {
klass = Class.forName(classname);
}
return klass;
}
/**
* Initialize this component according the KEY/VALUEs passed in
* via the <param> elements in the corresponding
* <object> element.
*/
private void setParameters(Component comp, AttributeSet attr) {
Class k = comp.getClass();
BeanInfo bi;
try {
bi = Introspector.getBeanInfo(k);
} catch (IntrospectionException ex) {
System.err.println("introspector failed, ex: "+ex);
return; // quit for now
}
PropertyDescriptor props[] = bi.getPropertyDescriptors();
for (int i=0; i < props.length; i++) {
// System.err.println("checking on props[i]: "+props[i].getName());
Object v = attr.getAttribute(props[i].getName());
if (v instanceof String) {
// found a property parameter
String value = (String) v;
Method writer = props[i].getWriteMethod();
if (writer == null) {
// read-only property. ignore
return; // for now
}
Class[] params = writer.getParameterTypes();
if (params.length != 1) {
// zero or more than one argument, ignore
return; // for now
}
Object [] args = { value };
try {
writer.invoke(comp, args);
} catch (Exception ex) {
System.err.println("Invocation failed");
// invocation code
}
}
}
}
}