public static void mergePluginLists( 
        PluginContainer childContainer, PluginContainer parentContainer,
        boolean handleAsInheritance) {
    if (childContainer == null || parentContainer == null) {
        // nothing to do.
        return;
    }

    List parentPlugins = parentContainer.getPlugins();
    if (parentPlugins == null || parentPlugins.isEmpty()) {
        return;
    }

    List childPlugins = childContainer.getPlugins();

    // clone the parent plugin map, since we'll be removing from it
    Map parentPluginMap = new HashMap(parentContainer.getPluginsAsMap());

    List mergedPlugins = new ArrayList(childPlugins.size());

    if (!childPlugins.isEmpty()) {
        for (Iterator itr = childPlugins.iterator(); itr.hasNext();) {
            Plugin childPlugin = (Plugin) itr.next();
            String key = childPlugin.getKey();
            Plugin parentPlugin = (Plugin) parentPluginMap.get(key);

            if (parentPlugin != null) {
                String parentInherited = parentPlugin.getInherited();
                if (!handleAsInheritance ||
                        parentInherited == null ||
                        Boolean.valueOf(parentInherited).booleanValue()) {
                    mergePluginDefinitions(
                            childPlugin, parentPlugin, handleAsInheritance);
                    if (handleAsInheritance && parentInherited == null) {
                        childPlugin.unsetInheritanceApplied();
                    }
                }
                parentPluginMap.remove(key);
            }
            mergedPlugins.add(childPlugin);
        }
    }

    int maxNewSize = mergedPlugins.size() + parentPluginMap.size();
    List newChildPlugins = new ArrayList(maxNewSize);

    for (Iterator itr = parentPlugins.iterator(); itr.hasNext();) {
        Plugin parentPlugin = (Plugin) itr.next();
        if (parentPluginMap.containsKey(parentPlugin.getKey())) {
            String parentInherited = parentPlugin.getInherited();
            if (!handleAsInheritance ||
                    parentInherited == null ||
                    Boolean.valueOf(parentInherited).booleanValue()) {
                if (handleAsInheritance && parentInherited == null) {
                    parentPlugin.unsetInheritanceApplied();
                }
                newChildPlugins.add(parentPlugin);
            }                
        }
    }

    newChildPlugins.addAll(mergedPlugins);

    childContainer.setPlugins(newChildPlugins);
    childContainer.flushPluginMap();
}