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A driver for Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol.

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/*
 * Copyright (C) 2012-2017 DataStax Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datastax.driver.core;

import com.datastax.driver.core.exceptions.UnsupportedFeatureException;
import com.datastax.driver.core.utils.MoreFutures;
import com.google.common.util.concurrent.Futures;

/**
 * Options related to defaults for individual queries.
 */
public class QueryOptions {

    /**
     * The default consistency level for queries: {@link ConsistencyLevel#LOCAL_ONE}.
     */
    public static final ConsistencyLevel DEFAULT_CONSISTENCY_LEVEL = ConsistencyLevel.LOCAL_ONE;

    /**
     * The default serial consistency level for conditional updates: {@link ConsistencyLevel#SERIAL}.
     */
    public static final ConsistencyLevel DEFAULT_SERIAL_CONSISTENCY_LEVEL = ConsistencyLevel.SERIAL;

    /**
     * The default fetch size for SELECT queries: 5000.
     */
    public static final int DEFAULT_FETCH_SIZE = 5000;

    /**
     * The default value for {@link #getDefaultIdempotence()}: {@code false}.
     */
    public static final boolean DEFAULT_IDEMPOTENCE = false;

    public static final int DEFAULT_MAX_PENDING_REFRESH_NODE_LIST_REQUESTS = 20;

    public static final int DEFAULT_MAX_PENDING_REFRESH_NODE_REQUESTS = 20;

    public static final int DEFAULT_MAX_PENDING_REFRESH_SCHEMA_REQUESTS = 20;

    public static final int DEFAULT_REFRESH_NODE_LIST_INTERVAL_MILLIS = 1000;

    public static final int DEFAULT_REFRESH_NODE_INTERVAL_MILLIS = 1000;

    public static final int DEFAULT_REFRESH_SCHEMA_INTERVAL_MILLIS = 1000;

    private volatile ConsistencyLevel consistency = DEFAULT_CONSISTENCY_LEVEL;
    private volatile ConsistencyLevel serialConsistency = DEFAULT_SERIAL_CONSISTENCY_LEVEL;
    private volatile int fetchSize = DEFAULT_FETCH_SIZE;
    private volatile boolean defaultIdempotence = DEFAULT_IDEMPOTENCE;

    private volatile boolean metadataEnabled = true;

    private volatile int maxPendingRefreshNodeListRequests = DEFAULT_MAX_PENDING_REFRESH_NODE_LIST_REQUESTS;
    private volatile int maxPendingRefreshNodeRequests = DEFAULT_MAX_PENDING_REFRESH_NODE_REQUESTS;
    private volatile int maxPendingRefreshSchemaRequests = DEFAULT_MAX_PENDING_REFRESH_SCHEMA_REQUESTS;

    private volatile int refreshNodeListIntervalMillis = DEFAULT_REFRESH_NODE_LIST_INTERVAL_MILLIS;
    private volatile int refreshNodeIntervalMillis = DEFAULT_REFRESH_NODE_INTERVAL_MILLIS;
    private volatile int refreshSchemaIntervalMillis = DEFAULT_REFRESH_SCHEMA_INTERVAL_MILLIS;

    private volatile boolean reprepareOnUp = true;
    private volatile Cluster.Manager manager;
    private volatile boolean prepareOnAllHosts = true;

    /**
     * Creates a new {@link QueryOptions} instance using the {@link #DEFAULT_CONSISTENCY_LEVEL},
     * {@link #DEFAULT_SERIAL_CONSISTENCY_LEVEL} and {@link #DEFAULT_FETCH_SIZE}.
     */
    public QueryOptions() {
    }

    void register(Cluster.Manager manager) {
        this.manager = manager;
    }

    /**
     * Sets the default consistency level to use for queries.
     * 

* The consistency level set through this method will be use for queries * that don't explicitly have a consistency level, i.e. when {@link Statement#getConsistencyLevel} * returns {@code null}. * * @param consistencyLevel the new consistency level to set as default. * @return this {@code QueryOptions} instance. */ public QueryOptions setConsistencyLevel(ConsistencyLevel consistencyLevel) { this.consistency = consistencyLevel; return this; } /** * The default consistency level used by queries. * * @return the default consistency level used by queries. */ public ConsistencyLevel getConsistencyLevel() { return consistency; } /** * Sets the default serial consistency level to use for queries. *

* The serial consistency level set through this method will be use for queries * that don't explicitly have a serial consistency level, i.e. when {@link Statement#getSerialConsistencyLevel} * returns {@code null}. * * @param serialConsistencyLevel the new serial consistency level to set as default. * @return this {@code QueryOptions} instance. */ public QueryOptions setSerialConsistencyLevel(ConsistencyLevel serialConsistencyLevel) { this.serialConsistency = serialConsistencyLevel; return this; } /** * The default serial consistency level used by queries. * * @return the default serial consistency level used by queries. */ public ConsistencyLevel getSerialConsistencyLevel() { return serialConsistency; } /** * Sets the default fetch size to use for SELECT queries. *

* The fetch size set through this method will be use for queries * that don't explicitly have a fetch size, i.e. when {@link Statement#getFetchSize} * is less or equal to 0. * * @param fetchSize the new fetch size to set as default. It must be * strictly positive but you can use {@code Integer.MAX_VALUE} to disable * paging. * @return this {@code QueryOptions} instance. * @throws IllegalArgumentException if {@code fetchSize <e; 0}. * @throws UnsupportedFeatureException if version 1 of the native protocol is in * use and {@code fetchSize != Integer.MAX_VALUE} as paging is not supported by * version 1 of the protocol. See {@link Cluster.Builder#withProtocolVersion} * for more details on protocol versions. */ public QueryOptions setFetchSize(int fetchSize) { if (fetchSize <= 0) throw new IllegalArgumentException("Invalid fetchSize, should be > 0, got " + fetchSize); ProtocolVersion version = manager == null ? null : manager.protocolVersion(); if (fetchSize != Integer.MAX_VALUE && version == ProtocolVersion.V1) throw new UnsupportedFeatureException(version, "Paging is not supported"); this.fetchSize = fetchSize; return this; } /** * The default fetch size used by queries. * * @return the default fetch size used by queries. */ public int getFetchSize() { return fetchSize; } /** * Sets the default idempotence for queries. *

* This will be used for statements for which {@link com.datastax.driver.core.Statement#isIdempotent()} * returns {@code null}. * * @param defaultIdempotence the new value to set as default idempotence. * @return this {@code QueryOptions} instance. */ public QueryOptions setDefaultIdempotence(boolean defaultIdempotence) { this.defaultIdempotence = defaultIdempotence; return this; } /** * The default idempotence for queries. *

* It defaults to {@link #DEFAULT_IDEMPOTENCE}. * * @return the default idempotence for queries. */ public boolean getDefaultIdempotence() { return defaultIdempotence; } /** * Set whether the driver should prepare statements on all hosts in the cluster. *

* A statement is normally prepared in two steps: *

    *
  1. prepare the query on a single host in the cluster;
  2. *
  3. if that succeeds, prepare on all other hosts.
  4. *
* This option controls whether step 2 is executed. It is enabled by default. *

* The reason why you might want to disable it is to optimize network usage if you * have a large number of clients preparing the same set of statements at startup. * If your load balancing policy distributes queries randomly, each client will pick * a different host to prepare its statements, and on the whole each host has a good * chance of having been hit by at least one client for each statement. *

* On the other hand, if that assumption turns out to be wrong and one host hasn't * prepared a given statement, it needs to be re-prepared on the fly the first time * it gets executed; this causes a performance penalty (one extra roundtrip to resend * the query to prepare, and another to retry the execution). * * @param prepareOnAllHosts the new value to set to indicate whether to prepare * statements once or on all nodes. * @return this {@code QueryOptions} instance. */ public QueryOptions setPrepareOnAllHosts(boolean prepareOnAllHosts) { this.prepareOnAllHosts = prepareOnAllHosts; return this; } /** * Returns whether the driver should prepare statements on all hosts in the cluster. * * @return the value. * @see #setPrepareOnAllHosts(boolean) */ public boolean isPrepareOnAllHosts() { return this.prepareOnAllHosts; } /** * Set whether the driver should re-prepare all cached prepared statements on a host * when it marks it back up. *

* This option is enabled by default. *

* The reason why you might want to disable it is to optimize reconnection time when * you believe hosts often get marked down because of temporary network issues, rather * than the host really crashing. In that case, the host still has prepared statements * in its cache when the driver reconnects, so re-preparing is redundant. *

* On the other hand, if that assumption turns out to be wrong and the host had * really restarted, its prepared statement cache is empty, and statements need to be * re-prepared on the fly the first time they get executed; this causes a performance * penalty (one extra roundtrip to resend the query to prepare, and another to retry * the execution). * * @param reprepareOnUp whether the driver should re-prepare when marking a node up. * @return this {@code QueryOptions} instance. */ public QueryOptions setReprepareOnUp(boolean reprepareOnUp) { this.reprepareOnUp = reprepareOnUp; return this; } /** * Whether the driver should re-prepare all cached prepared statements on a host * when its marks that host back up. * * @return the value. * @see #setReprepareOnUp(boolean) */ public boolean isReprepareOnUp() { return this.reprepareOnUp; } /** * Toggle client-side token and schema metadata. *

* This feature is enabled by default. Some applications might wish to disable it * in order to eliminate the overhead of querying the metadata and building its * client-side representation. However, take note that doing so will have important * consequences: *

    *
  • most schema- or token-related methods in {@link Metadata} will return stale * or null/empty results (see the javadoc of each method for details);
  • *
  • {@link Metadata#newToken(String)} and * {@link Metadata#newTokenRange(Token, Token)} will throw an exception if metadata * was disabled before startup;
  • *
  • token-aware routing will not work properly: if metadata was never initialized, * {@link com.datastax.driver.core.policies.TokenAwarePolicy} will always delegate * to its child policy. Otherwise, it might not pick the best coordinator (i.e. chose * a host that is not a replica for the statement's routing key). In addition, statements * prepared while the metadata was disabled might also be sent to a non-optimal coordinator, * even if metadata was re-enabled later.
  • *
* * @param enabled whether metadata is enabled. * @return this {@code QueryOptions} instance. */ public QueryOptions setMetadataEnabled(boolean enabled) { boolean wasEnabled = this.metadataEnabled; this.metadataEnabled = enabled; if (!wasEnabled && enabled && manager != null) { // This is roughly the same as what we do in ControlConnection.tryConnect(): // 1. call submitNodeListRefresh() first to // be able to compute the token map for the first time, // which will be incomplete due to the lack of keyspace metadata Futures.addCallback(manager.submitNodeListRefresh(), new MoreFutures.SuccessCallback() { @Override public void onSuccess(Void result) { // 2. then call submitSchemaRefresh() to // refresh schema metadata and re-compute the token map // this time with information about keyspaces manager.submitSchemaRefresh(null, null, null, null); } }); } return this; } /** * Whether client-side token and schema metadata is enabled. * * @return the value. * @see #setMetadataEnabled(boolean) */ public boolean isMetadataEnabled() { return metadataEnabled; } /** * Sets the default window size in milliseconds used to debounce node list refresh requests. *

* When the control connection receives a new schema refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * when a timer expires, then the pending requests are coalesced and executed * as a single request. * * @param refreshSchemaIntervalMillis The default window size in milliseconds used to debounce schema refresh requests. */ public QueryOptions setRefreshSchemaIntervalMillis(int refreshSchemaIntervalMillis) { this.refreshSchemaIntervalMillis = refreshSchemaIntervalMillis; return this; } /** * The default window size in milliseconds used to debounce schema refresh requests. * * @return The default window size in milliseconds used to debounce schema refresh requests. */ public int getRefreshSchemaIntervalMillis() { return refreshSchemaIntervalMillis; } /** * Sets the maximum number of schema refresh requests that the control connection can accumulate * before executing them. *

* When the control connection receives a new schema refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * if the control connection receives too many events, is parameter allows to trigger * execution of pending requests, event if the last timer is still running. * * @param maxPendingRefreshSchemaRequests The maximum number of schema refresh requests that the control connection can accumulate * before executing them. */ public QueryOptions setMaxPendingRefreshSchemaRequests(int maxPendingRefreshSchemaRequests) { this.maxPendingRefreshSchemaRequests = maxPendingRefreshSchemaRequests; return this; } /** * The maximum number of schema refresh requests that the control connection can accumulate * before executing them. * * @return The maximum number of schema refresh requests that the control connection can accumulate * before executing them. */ public int getMaxPendingRefreshSchemaRequests() { return maxPendingRefreshSchemaRequests; } /** * Sets the default window size in milliseconds used to debounce node list refresh requests. *

* When the control connection receives a new node list refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * when a timer expires, then the pending requests are coalesced and executed * as a single request. * * @param refreshNodeListIntervalMillis The default window size in milliseconds used to debounce node list refresh requests. */ public QueryOptions setRefreshNodeListIntervalMillis(int refreshNodeListIntervalMillis) { this.refreshNodeListIntervalMillis = refreshNodeListIntervalMillis; return this; } /** * The default window size in milliseconds used to debounce node list refresh requests. * * @return The default window size in milliseconds used to debounce node list refresh requests. */ public int getRefreshNodeListIntervalMillis() { return refreshNodeListIntervalMillis; } /** * Sets the maximum number of node list refresh requests that the control connection can accumulate * before executing them. *

* When the control connection receives a new node list refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * if the control connection receives too many events, is parameter allows to trigger * execution of pending requests, event if the last timer is still running. * * @param maxPendingRefreshNodeListRequests The maximum number of node list refresh requests that the control connection can accumulate * before executing them. */ public QueryOptions setMaxPendingRefreshNodeListRequests(int maxPendingRefreshNodeListRequests) { this.maxPendingRefreshNodeListRequests = maxPendingRefreshNodeListRequests; return this; } /** * Sets the maximum number of node list refresh requests that the control connection can accumulate * before executing them. * * @return The maximum number of node list refresh requests that the control connection can accumulate * before executing them. */ public int getMaxPendingRefreshNodeListRequests() { return maxPendingRefreshNodeListRequests; } /** * Sets the default window size in milliseconds used to debounce node refresh requests. *

* When the control connection receives a new node refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * when a timer expires, then the pending requests are coalesced and executed * as a single request. * * @param refreshNodeIntervalMillis The default window size in milliseconds used to debounce node refresh requests. */ public QueryOptions setRefreshNodeIntervalMillis(int refreshNodeIntervalMillis) { this.refreshNodeIntervalMillis = refreshNodeIntervalMillis; return this; } /** * The default window size in milliseconds used to debounce node refresh requests. * * @return The default window size in milliseconds used to debounce node refresh requests. */ public int getRefreshNodeIntervalMillis() { return refreshNodeIntervalMillis; } /** * Sets the maximum number of node refresh requests that the control connection can accumulate * before executing them. *

* When the control connection receives a new node refresh request, * it puts it on hold and starts a timer, cancelling any previous running timer; * if the control connection receives too many events, is parameter allows to trigger * execution of pending requests, event if the last timer is still running. * * @param maxPendingRefreshNodeRequests The maximum number of node refresh requests that the control connection can accumulate * before executing them. */ public QueryOptions setMaxPendingRefreshNodeRequests(int maxPendingRefreshNodeRequests) { this.maxPendingRefreshNodeRequests = maxPendingRefreshNodeRequests; return this; } /** * The maximum number of node refresh requests that the control connection can accumulate * before executing them. * * @return The maximum number of node refresh requests that the control connection can accumulate * before executing them. */ public int getMaxPendingRefreshNodeRequests() { return maxPendingRefreshNodeRequests; } }





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