public ZookeeprTickCondition(String workPath, ZkClient zkClient) {
this.zkClient = zkClient;
this.workPath = ZookeeperConstant.ROOT + "/" + workPath;
zkClient.createPersistent(this.workPath, true);
zkClient.subscribeChildChanges(
this.workPath,
new IZkChildListener() {
@Override
public void handleChildChange(String parentPath, List<String> currentChilds)
throws Exception {
if (currentChilds != null && !currentChilds.isEmpty()) {
return;
}
tryOccupy();
}
});
}
@SuppressWarnings("unchecked")
protected Element<T> getFirstElement() throws InterruptedException {
final Object mutex = new Object();
IZkChildListener notifyListener =
new IZkChildListener() {
@Override
public void handleChildChange(String parentPath, List<String> currentChilds)
throws Exception {
synchronized (mutex) {
mutex.notify();
}
}
};
try {
while (true) {
List<String> elementNames;
synchronized (mutex) {
elementNames = _zkClient.subscribeChildChanges(_elementsPath, notifyListener);
while (elementNames == null || elementNames.isEmpty()) {
mutex.wait();
elementNames = _zkClient.getChildren(_elementsPath);
}
}
String elementName = getSmallestElement(elementNames);
try {
String elementPath = getElementPath(elementName);
return new Element<T>(elementName, (T) _zkClient.readData(elementPath));
} catch (ZkNoNodeException e) {
// somebody else picked up the element first, so we have to
// retry with the new first element
}
}
} catch (InterruptedException e) {
throw e;
} catch (Exception e) {
throw ExceptionUtil.convertToRuntimeException(e);
} finally {
_zkClient.unsubscribeChildChanges(_elementsPath, notifyListener);
}
}
@Override
public List<String> addChildListener(String path, IZkChildListener listener) {
return client.subscribeChildChanges(path, listener);
}
public List<String> addTargetChildListener(String path, final IZkChildListener listener) {
return client.subscribeChildChanges(path, listener);
}
public static void subscribeChildChanges(String path, IZkChildListener listener) {
zkClient.subscribeChildChanges(path, listener);
}