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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Rhino code, released
* May 6, 1999.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1997-2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Norris Boyd
* Igor Bukanov
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License Version 2 or later (the "GPL"), in which
* case the provisions of the GPL are applicable instead of those above. If
* you wish to allow use of your version of this file only under the terms of
* the GPL and not to allow others to use your version of this file under the
* MPL, indicate your decision by deleting the provisions above and replacing
* them with the notice and other provisions required by the GPL. If you do
* not delete the provisions above, a recipient may use your version of this
* file under either the MPL or the GPL.
*
* ***** END LICENSE BLOCK ***** */
package org.mozilla.javascript;
import java.lang.reflect.*;
/**
* Avoid loading classes unless they are used.
*
* This improves startup time and average memory usage.
*/
public final class LazilyLoadedCtor implements java.io.Serializable {
private static final long serialVersionUID = 1L;
private static final int STATE_BEFORE_INIT = 0;
private static final int STATE_INITIALIZING = 1;
private static final int STATE_WITH_VALUE = 2;
private final ScriptableObject scope;
private final String propertyName;
private final String className;
private final boolean sealed;
private Object initializedValue;
private int state;
public LazilyLoadedCtor(ScriptableObject scope, String propertyName,
String className, boolean sealed)
{
this.scope = scope;
this.propertyName = propertyName;
this.className = className;
this.sealed = sealed;
this.state = STATE_BEFORE_INIT;
scope.addLazilyInitializedValue(propertyName, 0, this,
ScriptableObject.DONTENUM);
}
void init()
{
synchronized (this) {
if (state == STATE_INITIALIZING)
throw new IllegalStateException(
"Recursive initialization for "+propertyName);
if (state == STATE_BEFORE_INIT) {
state = STATE_INITIALIZING;
// Set value now to have something to set in finally block if
// buildValue throws.
Object value = Scriptable.NOT_FOUND;
try {
value = buildValue();
} finally {
initializedValue = value;
state = STATE_WITH_VALUE;
}
}
}
}
Object getValue()
{
if (state != STATE_WITH_VALUE)
throw new IllegalStateException(propertyName);
return initializedValue;
}
private Object buildValue()
{
Class cl = cast(Kit.classOrNull(className));
if (cl != null) {
try {
Object value = ScriptableObject.buildClassCtor(scope, cl,
sealed, false);
if (value != null) {
return value;
}
else {
// cl has own static initializer which is expected
// to set the property on its own.
value = scope.get(propertyName, scope);
if (value != Scriptable.NOT_FOUND)
return value;
}
} catch (InvocationTargetException ex) {
Throwable target = ex.getTargetException();
if (target instanceof RuntimeException) {
throw (RuntimeException)target;
}
} catch (RhinoException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (SecurityException ex) {
}
}
return Scriptable.NOT_FOUND;
}
@SuppressWarnings({"unchecked"})
private Class cast(Class cl) {
return (Class)cl;
}
}