public final T build() {
        if (!built.compareAndSet(false, true)) {
            throw new IllegalStateException("Already Built");
        }
        checkLocations();
        T node = build0();
        if (masterChangeListeners != null) {
            for (MasterChangeListener masterChangeListener : masterChangeListeners) {
                node.addMasterChangeListener(masterChangeListener);
            }
        }
        return node;
    }
@author Robert HG (254963746@qq.com) on 4/21/16.
lts-core/src/main/java/com/github/ltsopensource/core/cluster/AbstractNodeBuilder.java