com.google.gwt.core.translatable.com.google.gwt.core.client.impl.WeakMapping Maven / Gradle / Ivy
/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.core.client.impl;
import com.google.gwt.core.client.GwtScriptOnly;
/**
* A class associating a (String, Object) map with arbitrary source objects
* (except for Strings). This implementation is used in web mode.
*/
@GwtScriptOnly
public class WeakMapping {
/*
* This implementation is used in web mode only. It stores the (key, value)
* maps in an expando field on their source objects.
*/
/**
* Returns the Object associated with the given key in the (key, value)
* mapping associated with the given Object instance.
*
* @param instance the source Object.
* @param key a String key.
* @return an Object associated with that key on the given instance, or null.
*/
public static native Object get(Object instance, String key) /*-{
if ([email protected]::expando) {
return [email protected]::expando[':' + key];
}
return null;
}-*/;
/**
* Associates a value with a given key in the (key, value) mapping associated
* with the given Object instance. Note that the key space is module-wide, so
* some care should be taken to choose sufficiently unique identifiers.
*
* @param instance the source Object.
* @param key a String key.
* @param value the Object to associate with the key on the given source
* Object.
*/
public static void set(Object instance, String key, Object value) {
assert !(instance instanceof String) : "Cannot use Strings with WeakMapping";
setNative(instance, key, value);
}
public static void setWeak(Object instance, String key, Object value) {
set(instance, key, value);
}
private static native void setNative(Object instance, String key, Object value) /*-{
if ([email protected]::expando) {
[email protected]::expando = {};
}
[email protected]::expando[':' + key] = value;
}-*/;
}