/*
GNU LESSER GENERAL PUBLIC LICENSE
Copyright (C) 2006 The Lobo Project
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Contact info: lobochief@users.sourceforge.net
*/
package org.lobobrowser.js;
import java.lang.ref.WeakReference;
import java.util.WeakHashMap;
import org.lobobrowser.util.Objects;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.ContextFactory;
import org.mozilla.javascript.Scriptable;
public class JavaScript {
// TODO: Should the instance be specific to thread? GH #122
private static JavaScript instance = new JavaScript();
// objectMap must be a map that uses weak keys
// and refers to values using weak references.
// Keys are java objects other than ScriptableDelegate instances.
private final WeakHashMap<Object, WeakReference<JavaObjectWrapper>> javaObjectToWrapper = new WeakHashMap<>();
public static JavaScript getInstance() {
return instance;
}
public static void init() {
ContextFactory.initGlobal(new ContextFactory() {
@Override
protected Context makeContext() {
throw new UnsupportedOperationException("Internal error. Global context factory should not be used.");
}
});
}
/**
* Returns an object that may be used by the Javascript engine.
*
* @param raw
* @return
*/
public Object getJavascriptObject(final Object raw, final Scriptable scope) {
if ((raw instanceof String) || (raw instanceof Scriptable)) {
return raw;
} else if (raw == null) {
return null;
} else if (raw.getClass().isPrimitive()) {
return raw;
} else if (raw.getClass().isArray()) {
return raw;
} else if (raw instanceof ScriptableDelegate) {
// Classes that implement ScriptableDelegate retain
// the JavaScript object. Reciprocal linking cannot
// be done with weak hash maps and without leaking.
synchronized (this) {
final ScriptableDelegate delegate = (ScriptableDelegate) raw;
Scriptable javascriptObject = delegate.getScriptable();
if (javascriptObject == null) {
final JavaObjectWrapper jow = new JavaObjectWrapper(JavaClassWrapperFactory.getInstance().getClassWrapper(raw.getClass()), raw);
javascriptObject = jow;
jow.setParentScope(scope);
delegate.setScriptable(jow);
} else {
javascriptObject.setParentScope(scope);
}
return javascriptObject;
}
} else if (Objects.isBoxClass(raw.getClass())) {
return raw;
} else {
synchronized (this.javaObjectToWrapper) {
// WeakHashMaps will retain keys if the value refers to the key.
// That's why we need to refer to the value weakly too.
// TODO: The above comment should probably be moved to the context of the code further below
// where the value is being inserted into the map.
// This part of the code is simply querying an existing value.
final WeakReference<?> valueRef = this.javaObjectToWrapper.get(raw);
JavaObjectWrapper jow = null;
if (valueRef != null) {
jow = (JavaObjectWrapper) valueRef.get();
}
if (jow == null) {
final Class<? extends Object> javaClass = raw.getClass();
final JavaClassWrapper wrapper = JavaClassWrapperFactory.getInstance().getClassWrapper(javaClass);
jow = new JavaObjectWrapper(wrapper, raw);
this.javaObjectToWrapper.put(raw, new WeakReference<>(jow));
}
jow.setParentScope(scope);
return jow;
}
}
}
/*
private static String getStringValue(final Object object) {
if (object instanceof Undefined) {
return "undefined";
} else if (object instanceof Scriptable) {
return (String) ((Scriptable) object).getDefaultValue(String.class);
} else {
return String.valueOf(object);
}
}
*/
public Object getJavaObject(final Object javascriptObject, final Class<?> type) {
if (javascriptObject instanceof JavaObjectWrapper) {
final Object rawJavaObject = ((JavaObjectWrapper) javascriptObject).getJavaObject();
if (String.class == type) {
return String.valueOf(rawJavaObject);
} else {
return rawJavaObject;
}
}
// Relying on Rhino to do the right thing.
// TODO: Remove the older implementation archived below.
return Context.jsToJava(javascriptObject, type);
}
/*
public Object getJavaObject(final Object javascriptObject, final Class<?> type) {
if (type == Boolean.TYPE) {
if ((javascriptObject == null) || (javascriptObject == Undefined.instance)) {
return Boolean.FALSE;
}
}
if (javascriptObject instanceof JavaObjectWrapper) {
final Object rawJavaObject = ((JavaObjectWrapper) javascriptObject).getJavaObject();
if (String.class == type) {
return String.valueOf(rawJavaObject);
} else {
return rawJavaObject;
}
} else if (javascriptObject == null) {
return null;
} else if (type == String.class) {
if (javascriptObject instanceof String) {
return javascriptObject;
} else if (javascriptObject instanceof Double) {
final String text = String.valueOf(javascriptObject);
if (text.endsWith(".0")) {
return text.substring(0, text.length() - 2);
} else {
return text;
}
} else {
return getStringValue(javascriptObject);
}
} else if ((type == int.class) || (type == Integer.class)) {
if (javascriptObject instanceof Double) {
return new Integer(((Double) javascriptObject).intValue());
} else if (javascriptObject instanceof Integer) {
return javascriptObject;
} else if (javascriptObject instanceof String) {
return Integer.valueOf((String) javascriptObject);
} else if (javascriptObject instanceof Short) {
return new Integer(((Short) javascriptObject).shortValue());
} else if (javascriptObject instanceof Long) {
return new Integer(((Long) javascriptObject).intValue());
} else if (javascriptObject instanceof Float) {
return new Integer(((Float) javascriptObject).intValue());
} else {
return javascriptObject;
}
} else {
return javascriptObject;
}
}
*/
// Convenience method; useful when debugging
public static String getStackTrace() {
return org.mozilla.javascript.ScriptRuntime.constructError("", "").getScriptStackTrace();
}
}