javax.faces.component.StateHolderSaver Maven / Gradle / Ivy
/*
* $Id: StateHolderSaver.java,v 1.16.4.1 2008/12/08 18:07:13 rlubke Exp $
*/
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package javax.faces.component;
import javax.faces.context.FacesContext;
import java.io.Serializable;
/**
* Helper class for saving and restoring attached objects.
*/
class StateHolderSaver implements Serializable {
private static final long serialVersionUID = 6470180891722042701L;
private String className = null;
private Serializable savedState = null;
public StateHolderSaver(FacesContext context, Object toSave) {
className = toSave.getClass().getName();
if (toSave instanceof StateHolder) {
// do not save an attached object that is marked transient.
if (!((StateHolder)toSave).isTransient()) {
savedState = (Serializable) ((StateHolder)toSave).saveState(context);
} else {
className = null;
}
}
else if (toSave instanceof Serializable) {
savedState = (Serializable) toSave;
className = null;
}
}
/**
*
* @return the restored {@link StateHolder} instance.
*/
public Object restore(FacesContext context) throws IllegalStateException {
Object result = null;
Class toRestoreClass;
// if the Object to save implemented Serializable but not
// StateHolder
if (null == className && null != savedState) {
return savedState;
}
// if the Object to save did not implement Serializable or
// StateHolder
if ( className == null) {
return null;
}
// else the object to save did implement StateHolder
try {
toRestoreClass = loadClass(className, this);
}
catch (ClassNotFoundException e) {
throw new IllegalStateException(e);
}
if (null != toRestoreClass) {
try {
result = toRestoreClass.newInstance();
}
catch (InstantiationException e) {
throw new IllegalStateException(e);
}
catch (IllegalAccessException a) {
throw new IllegalStateException(a);
}
}
if (null != result && null != savedState &&
result instanceof StateHolder) {
// don't need to check transient, since that was done on
// the saving side.
((StateHolder)result).restoreState(context, savedState);
}
return result;
}
private static Class loadClass(String name,
Object fallbackClass) throws ClassNotFoundException {
ClassLoader loader =
Thread.currentThread().getContextClassLoader();
if (loader == null) {
loader = fallbackClass.getClass().getClassLoader();
}
return Class.forName(name, false, loader);
}
}