实践zookeeper之curator

Curator n ˈkyoor͝ˌātər: a keeper or custodian of a museum or other collection - A ZooKeeper Keeper.
Apache Curator is a Java/JVM client library for Apache ZooKeeper, a distributed coordination service. It includes a highlevel API framework and utilities to make using Apache ZooKeeper much easier and more reliable. It also includes recipes for common use cases and extensions such as service discovery and a Java 8 asynchronous DSL.
CuratorFrameworkFactory

public static CuratorFramework newClient(String connectString, RetryPolicy retryPolicy)
public static CuratorFramework newClient(String connectString, int sessionTimeoutMs, int connectionTimeoutMs, RetryPolicy retryPolicy)
builder()
CuratorFramework

state

状态
CreateBuilder

DeleteBuilder

ExistsBuilder

SetDataBuilder

GetDataBuilder

GetChildrenBuilder

GetACLBuilder

SetACLBuilder

ReconfigBuilder

GetConfigBuilder

transaction

事务
4.0.1源码

package org.apache.curator.framework;

import org.apache.curator.CuratorZookeeperClient;
import org.apache.curator.framework.api.*;
import org.apache.curator.framework.api.transaction.CuratorMultiTransaction;
import org.apache.curator.framework.api.transaction.CuratorOp;
import org.apache.curator.framework.api.transaction.CuratorTransaction;
import org.apache.curator.framework.api.transaction.TransactionOp;
import org.apache.curator.framework.imps.CuratorFrameworkImpl;
import org.apache.curator.framework.imps.CuratorFrameworkState;
import org.apache.curator.framework.listen.Listenable;
import org.apache.curator.framework.schema.SchemaSet;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.framework.state.ConnectionStateErrorPolicy;
import org.apache.curator.utils.EnsurePath;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.server.quorum.flexible.QuorumVerifier;

import java.io.Closeable;
import java.util.concurrent.TimeUnit;

/**
 * Zookeeper framework-style client
 */
public interface CuratorFramework extends Closeable
{
    /**
     * Start the client. Most mutator methods will not work until the client is started
     */
    public void start();

    /**
     * Stop the client
     */
    public void close();

    /**
     * Returns the state of this instance
     *
     * @return state
     */
    public CuratorFrameworkState getState();

    /**
     * Return true if the client is started, not closed, etc.
     *
     * @return true/false
     * @deprecated use {@link #getState()} instead
     */
    @Deprecated
    public boolean isStarted();

    /**
     * Start a create builder
     *
     * @return builder object
     */
    public CreateBuilder create();

    /**
     * Start a delete builder
     *
     * @return builder object
     */
    public DeleteBuilder delete();

    /**
     * Start an exists builder
     * <p>
     * The builder will return a Stat object as if org.apache.zookeeper.ZooKeeper.exists() were called.  Thus, a null
     * means that it does not exist and an actual Stat object means it does exist.
     *
     * @return builder object
     */
    public ExistsBuilder checkExists();

    /**
     * Start a get data builder
     *
     * @return builder object
     */
    public GetDataBuilder getData();

    /**
     * Start a set data builder
     *
     * @return builder object
     */
    public SetDataBuilder setData();

    /**
     * Start a get children builder
     *
     * @return builder object
     */
    public GetChildrenBuilder getChildren();

    /**
     * Start a get ACL builder
     *
     * @return builder object
     */
    public GetACLBuilder getACL();

    /**
     * Start a set ACL builder
     *
     * @return builder object
     */
    public SetACLBuilder setACL();

    /**
     * Start a reconfig builder
     *
     * @return builder object
     */
    public ReconfigBuilder reconfig();

    /**
     * Start a getConfig builder
     *
     * @return builder object
     */
    public GetConfigBuilder getConfig();

    /**
     * Start a transaction builder
     *
     * @return builder object
     * @deprecated use {@link #transaction()} instead
     */
    public CuratorTransaction inTransaction();

    /**
     * Start a transaction builder
     *
     * @return builder object
     */
    public CuratorMultiTransaction transaction();

    /**
     * Allocate an operation that can be used with {@link #transaction()}.
     * NOTE: {@link CuratorOp} instances created by this builder are
     * reusable.
     *
     * @return operation builder
     */
    public TransactionOp transactionOp();

    /**
     * Perform a sync on the given path - syncs are always in the background
     *
     * @param path                    the path
     * @param backgroundContextObject optional context
     * @deprecated use {@link #sync()} instead
     */
    @Deprecated
    public void sync(String path, Object backgroundContextObject);

    /**
     * Create all nodes in the specified path as containers if they don't
     * already exist
     *
     * @param path path to create
     * @throws Exception errors
     */
    public void createContainers(String path) throws Exception;

    /**
     * Start a sync builder. Note: sync is ALWAYS in the background even
     * if you don't use one of the background() methods
     *
     * @return builder object
     */
    public SyncBuilder sync();

    /**
     * Start a remove watches builder.
     * @return builder object
     */
    public RemoveWatchesBuilder watches();

    /**
     * Returns the listenable interface for the Connect State
     *
     * @return listenable
     */
    public Listenable<ConnectionStateListener> getConnectionStateListenable();

    /**
     * Returns the listenable interface for events
     *
     * @return listenable
     */
    public Listenable<CuratorListener> getCuratorListenable();

    /**
     * Returns the listenable interface for unhandled errors
     *
     * @return listenable
     */
    public Listenable<UnhandledErrorListener> getUnhandledErrorListenable();

    /**
     * Returns a facade of the current instance that does _not_ automatically
     * pre-pend the namespace to all paths
     *
     * @return facade
     * @deprecated Since 2.9.0 - use {@link #usingNamespace} passing <code>null</code>
     */
    @Deprecated
    public CuratorFramework nonNamespaceView();

    /**
     * Returns a facade of the current instance that uses the specified namespace
     * or no namespace if <code>newNamespace</code> is <code>null</code>.
     *
     * @param newNamespace the new namespace or null for none
     * @return facade
     */
    public CuratorFramework usingNamespace(String newNamespace);

    /**
     * Return the current namespace or "" if none
     *
     * @return namespace
     */
    public String getNamespace();

    /**
     * Return the managed zookeeper client
     *
     * @return client
     */
    public CuratorZookeeperClient getZookeeperClient();

    /**
     * Allocates an ensure path instance that is namespace aware
     *
     * @param path path to ensure
     * @return new EnsurePath instance
     * @deprecated Since 2.9.0 - prefer {@link CreateBuilder#creatingParentContainersIfNeeded()}, {@link ExistsBuilder#creatingParentContainersIfNeeded()}
     * or {@link CuratorFramework#createContainers(String)}
     */
    @Deprecated
    public EnsurePath newNamespaceAwareEnsurePath(String path);

    /**
     * Curator can hold internal references to watchers that may inhibit garbage collection.
     * Call this method on watchers you are no longer interested in.
     *
     * @param watcher the watcher
     * 
     * @deprecated As of ZooKeeper 3.5 Curators recipes will handle removing watcher references
     * when they are no longer used. If you write your own recipe, follow the example of Curator
     * recipes and use {@link #newWatcherRemoveCuratorFramework} calling {@link WatcherRemoveCuratorFramework#removeWatchers()}
     * when closing your instance.
     */
    @Deprecated
    public void clearWatcherReferences(Watcher watcher);
        
    /**
     * Block until a connection to ZooKeeper is available or the maxWaitTime has been exceeded
     * @param maxWaitTime The maximum wait time. Specify a value &lt;= 0 to wait indefinitely
     * @param units The time units for the maximum wait time.
     * @return True if connection has been established, false otherwise.
     * @throws InterruptedException If interrupted while waiting
     */
    public boolean blockUntilConnected(int maxWaitTime, TimeUnit units) throws InterruptedException;
    
    /**
     * Block until a connection to ZooKeeper is available. This method will not return until a
     * connection is available or it is interrupted, in which case an InterruptedException will
     * be thrown
     * @throws InterruptedException If interrupted while waiting
     */
    public void blockUntilConnected() throws InterruptedException;

    /**
     * Returns a facade of the current instance that tracks
     * watchers created and allows a one-shot removal of all watchers
     * via {@link WatcherRemoveCuratorFramework#removeWatchers()}
     *
     * @return facade
     */
    public WatcherRemoveCuratorFramework newWatcherRemoveCuratorFramework();

    /**
     * Return the configured error policy
     *
     * @return error policy
     */
    public ConnectionStateErrorPolicy getConnectionStateErrorPolicy();

    /**
     * Current maintains a cached view of the Zookeeper quorum config.
     *
     * @return the current config
     */
    public QuorumVerifier getCurrentConfig();

    /**
     * Return this instance's schema set
     *
     * @return schema set
     */
    SchemaSet getSchemaSet();

    /**
     * Return true if this instance is running in ZK 3.4.x compatibility mode
     *
     * @return true/false
     */
    boolean isZk34CompatibilityMode();
}