/**
* Return the stat of the node of the given path. Return null if no such a node exists.
*
* <p>If the watch is non-null and the call is successful (no exception is thrown), a watch will
* be left on the node with the given path. The watch will be triggered by a successful operation
* that creates/delete the node or sets the data on the node.
*
* @param path the node path
* @param watcher explicit watcher
* @return the stat of the node of the given path; return null if no such a node exists.
* @throws KeeperException If the server signals an error
* @throws InterruptedException If the server transaction is interrupted.
* @throws IllegalArgumentException if an invalid path is specified
*/
public Stat exists(final String path, Watcher watcher)
throws KeeperException, InterruptedException {
final String clientPath = path;
PathUtils.validatePath(clientPath);
// the watch contains the un-chroot path
WatchRegistration wcb = null;
if (watcher != null) {
wcb = new ExistsWatchRegistration(watcher, clientPath);
}
final String serverPath = prependChroot(clientPath);
RequestHeader h = new RequestHeader();
h.setType(ZooDefs.OpCode.exists);
ExistsRequest request = new ExistsRequest();
request.setPath(serverPath);
request.setWatch(watcher != null);
SetDataResponse response = new SetDataResponse();
ReplyHeader r = cnxn.submitRequest(h, request, response, wcb);
if (r.getErr() != 0) {
if (r.getErr() == KeeperException.Code.NONODE.intValue()) {
return null;
}
throw KeeperException.create(KeeperException.Code.get(r.getErr()), clientPath);
}
return response.getStat().getCzxid() == -1 ? null : response.getStat();
}
/**
* Set the data for the node of the given path if such a node exists and the given version matches
* the version of the node (if the given version is -1, it matches any node's versions). Return
* the stat of the node.
*
* <p>This operation, if successful, will trigger all the watches on the node of the given path
* left by getData calls.
*
* <p>A KeeperException with error code KeeperException.NoNode will be thrown if no node with the
* given path exists.
*
* <p>A KeeperException with error code KeeperException.BadVersion will be thrown if the given
* version does not match the node's version.
*
* <p>The maximum allowable size of the data array is 1 MB (1,048,576 bytes). Arrays larger than
* this will cause a KeeperExecption to be thrown.
*
* @param path the path of the node
* @param data the data to set
* @param version the expected matching version
* @return the state of the node
* @throws InterruptedException If the server transaction is interrupted.
* @throws KeeperException If the server signals an error with a non-zero error code.
* @throws IllegalArgumentException if an invalid path is specified
*/
public Stat setData(final String path, byte data[], int version)
throws KeeperException, InterruptedException {
final String clientPath = path;
PathUtils.validatePath(clientPath);
final String serverPath = prependChroot(clientPath);
RequestHeader h = new RequestHeader();
h.setType(ZooDefs.OpCode.setData);
SetDataRequest request = new SetDataRequest();
request.setPath(serverPath);
request.setData(data);
request.setVersion(version);
SetDataResponse response = new SetDataResponse();
ReplyHeader r = cnxn.submitRequest(h, request, response, null);
if (r.getErr() != 0) {
throw KeeperException.create(KeeperException.Code.get(r.getErr()), clientPath);
}
return response.getStat();
}