@Override
    public <T extends Node> void install(String key, ToolbarItem<T> item) {
        injector.inject(item);
        final ToolbarItem<?> oldItem = byKey.put(key, item);
        if (oldItem == null) {
            switch (item.getSide()) {
                case LEFT:  leftSide.add(item); break;
                case RIGHT: rightSide.add(item); break;
                default: throw new UnsupportedOperationException(format(
                    "Unknown enum constant '%s'.", item.getSide()));
            }
        } else {
            switch (oldItem.getSide()) {
                case LEFT:  leftSide.set(leftSide.indexOf(oldItem), item); break;
                case RIGHT: rightSide.set(rightSide.indexOf(oldItem), item); break;
                default: throw new UnsupportedOperationException(format(
                    "Unknown enum constant '%s'.", item.getSide()));
            }
        }
    }
Default implementation of the {@link ToolbarComponent}-interface.

@author Emil Forslund
@since  3.1.5
tool-parent/tool-core/src/main/java/com/speedment/tool/core/internal/toolbar/ToolbarComponentImpl.java