public class DescribeQuotasOptions extends AbstractOptions<DescribeQuotasOptions> {
    // Empty.
}

/**
 * The result of the {@link Admin#describeQuotas(Collection<QuotaFilter>, DescribeQuotasOptions)} call.
 */
public class DescribeQuotasResult {

    /**
     * Maps an entity to its configured quota value(s). Note if no value is defined for a quota
     * type for that entity's config, then it is not included in the resulting value map.
     *
     * @param entities the collection of entities that matched the filter
     */
    public DescribeQuotasResult(KafkaFuture<Map<QuotaEntity, Map<QuotaKey, Long>>> entities);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public KafkaFuture<Map<QuotaEntity, Map<QuotaKey, Long>>> entities();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Describes all entities matching all provided filters (logical AND) that have at least one
     * quota value defined.
     *
     * @param filters filtering rules to apply to matching entities
     * @param options the options to use
     * @return result containing all matching entities
     */
    DescribeQuotasResult describeQuotas(Collection<QuotaFilter> filters, DescribeQuotasOptions options);
}

public class DescribeEffectiveQuotasOptions extends AbstractOptions<DescribeEffectiveQuotasOptions> {

    /**
     * Whether to exclude the list of overridden values for every quota type in the result.
     */
    public DescribeEffectiveQuotasOptions setOmitOverriddenValues(boolean omitOverriddenValues);
}

/**
 * The result of the {@link Admin#describeEffectiveQuotas(Collection<QuotaEntity>, DescribeEffectiveQuotasOptions)} call.
 */
public class DescribeEffectiveQuotasResult {
    /**
     * Information about a specific quota configuration entry.
     */
    public class Entry {
        /**
         * @param source the entity source for the value
         * @param value the non-null value
         */
        public Entry(QuotaEntity source, Long value);
    }

    /**
     * Information about the value for a quota type.
     */
    public class Value {
        /**
         * @param entry the quota entry
         * @param overriddenEntries all values that are overridden due to being lower in
         *                          specificity, or null if not requested
         */
        public Value(Entry entry, List<Entry> overriddenEntries);
    }

    /**
     * Maps a collection of entities to their effective quota values.
     *
     * @param config the quota configuration for the requested entities
     */
    public DescribeEffectiveQuotasResult(Map<QuotaEntity, KafkaFuture<Map<QuotaKey, Value>>> config);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<QuotaEntity, KafkaFuture<Map<QuotaKey, Value>>> config();

    /**
     * Returns a future which succeeds only if all quota descriptions succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Describes the effective quotas for the provided entities.
     *
     * @param entities the entities to describe the effective quotas for
     * @param options the options to use
     * @return the effective quotas for the entities
     */
    DescribeEffectiveQuotasResult describeEffectiveQuotas(Collection<QuotaEntity> entities, DescribeEffectiveQuotasOptions options);
}

public class AlterQuotasEntry {
    public class Op {
        /**
         * @param key the quota type and units to alter
         * @param value if set then the existing value is updated,
         *              otherwise if null, the existing value is cleared
         */
        public Op(QuotaKey key, Long value);
    }

    /**
     * @param entity the entity whose config will be modified
     * @param ops the alteration to perform - if value is set, then the existing value is updated,
     *            otherwise if null, the existing value is cleared
     */
    public AlterQuotasEntry(QuotaEntity entity, Collection<Op> ops);
}

public class AlterQuotasOptions extends AbstractOptions<AlterQuotasOptions> {
    /**
     * Sets whether the request should be validated without altering the configs.
     */
    public AlterQuotasOptions validateOnly(boolean validateOnly);
}

/**
 * The result of the {@link Admin#alterQuotas(Collection<AlterQuotasEntry>, AlterQuotasOptions)} call.
 *
 * The API of this class is evolving, see {@link Admin} for details.
 */
public class AlterQuotasResult {
    public AlterQuotasResult(Map<QuotaEntity, KafkaFuture<Void>> futures);

    /**
     * Returns a map from quota entity to a future which can be used to check the status of the operation.
     */
    public Map<QuotaEntity, KafkaFuture<Void>> values();

    /**
     * Returns a future which succeeds only if all quota alterations succeed.
     */
    public KafkaFuture<Void> all();
}

public interface Admin extends AutoCloseable {
    ...

    /**
     * Alters the quotas as specified for the entries.
     *
     * @param alterations the alterations to perform
     * @return the result of the alterations
     */
    AlterQuotasResult alterQuotas(Collection<AlterQuotasEntry> entries, AlterQuotasOptions options);
}

$./bin/kafka-quotas.sh --bootstrap-server localhost:9092 --describe \
                       --names=client-id=my-client --defaults=user  \
                       --add=producer_byte_rate:shares=100          \
                       --delete=producer_byte_rate:broker_bps

<no output on success>

$./bin/kafka-quotas.sh --bootstrap-server localhost:9092 --list     \
                       --names=client-id=my-client --defaults=user

{user=<default>, client-id=my-client}
consumer_byte_rate:shares=100
producer_byte_rate:shares=100

{
  "apiKey": 50,
  "type": "request",
  "name": "AlterQuotasRequest",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",
        "about": "The quota entity to alter.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The name of the entity." }
      ]},
      { "name": "Op", "type": "[]OpData", "versions": "0+",
        "about": "An individual quota configuration entry to alter.", "fields": [
        { "name": "Type", "type": "string", "versions": "0+",
          "about": "The quota type." },
        { "name": "Units", "type": "string", "versions": "0+",
          "about": "The units for the quota type." },
        { "name": "Value", "type": "int64", "versions": "0+",
          "about": "The value to set, otherwise ignored if the value is to be removed." },
        { "name": "Remove", "type": "bool", "versions": "0+",
          "about": "Whether the quota configuration value should be removed, otherwise set." }
      ]}
    ]},
    { "name": "ValidateOnly", "type": "bool", "versions": "0+",
      "about": "Whether the alteration should be validated, but not performed." }
  ]
}

{
  "apiKey": 50,
  "type": "response",
  "name": "AlterQuotasResponse",
  "validVersions": "0",
  "flexibleVersions": "none",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "Entry", "type": "[]EntryData", "versions": "0+",
      "about": "The quota configuration entries to alter.", "fields": [
      { "name": "ErrorCode", "type": "int16", "versions": "0+",
        "about": "The error code, or `0` if the quota alteration succeeded." },
      { "name": "ErrorMessage", "type": "string", "versions": "0+", "nullableVersions": "0+",
        "about": "The error message, or `null` if the quota alteration succeeded." },
      { "name": "QuotaEntity", "type": "[]QuotaEntity", "versions": "0+",
        "about": "The quota entity to alter.", "fields": [
        { "name": "EntityType", "type": "string", "versions": "0+",
          "about": "The entity type." },
        { "name": "EntityName", "type": "string", "versions": "0+",
          "about": "The name of the entity." }
      ]}
    ]}
  ]
}