/*
* Copyright 2011-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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://aws.amazon.com/apache2.0
*
* This file 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.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper;
import com.amazonaws.metrics.RequestMetricCollector;
/**
* Immutable configuration object for service call behavior. An instance of this
* configuration is supplied to every {@link DynamoDBMapper} at construction; if
* not provided explicitly, {@link DynamoDBMapperConfig#DEFAULT} is used. New
* instances can be given to the mapper object on individual save, load, and
* delete operations to override the defaults. For example:
*
* <pre class="brush: java">
* DynamoDBMapper mapper = new DynamoDBMapper(dynamoDBClient);
* // Force this read to be consistent
* DomainClass obj = mapper.load(DomainClass.class, key, new DynamoDBMapperConfig(
* ConsistentReads.CONSISTENT));
* // Force this save operation to use putItem rather than updateItem
* mapper.save(obj, new DynamoDBMapperConfig(SaveBehavior.CLOBBER));
* // Save the object into a different table
* mapper.save(obj, new DynamoDBMapperConfig(new TableNameOverride("AnotherTable")));
* // Delete the object even if the version field is out of date
* mapper.delete(obj, new DynamoDBMapperConfig(SaveBehavior.CLOBBER));
* </pre>
*/
public class DynamoDBMapperConfig {
/**
* A fluent builder for DynamoDBMapperConfig objects.
*/
public static class Builder {
private SaveBehavior saveBehavior;
private ConsistentReads consistentReads;
private TableNameOverride tableNameOverride;
private TableNameResolver tableNameResolver;
private ObjectTableNameResolver objectTableNameResolver;
private PaginationLoadingStrategy paginationLoadingStrategy;
private RequestMetricCollector requestMetricCollector;
private ConversionSchema conversionSchema;
/**
* Creates a new builder initialized with the {@link #DEFAULT} values.
*/
public Builder() {
saveBehavior = DEFAULT.getSaveBehavior();
consistentReads = DEFAULT.getConsistentReads();
tableNameOverride = DEFAULT.getTableNameOverride();
tableNameResolver = DEFAULT.getTableNameResolver();
objectTableNameResolver = DEFAULT.getObjectTableNameResolver();
paginationLoadingStrategy = DEFAULT.getPaginationLoadingStrategy();
requestMetricCollector = DEFAULT.getRequestMetricCollector();
conversionSchema = DEFAULT.getConversionSchema();
}
/**
* @return the currently-configured save behavior
*/
public SaveBehavior getSaveBehavior() {
return saveBehavior;
}
/**
* @param value the new save behavior
*/
public void setSaveBehavior(SaveBehavior value) {
saveBehavior = value;
}
/**
* @param value the new save behavior
* @return this builder
*/
public Builder withSaveBehavior(SaveBehavior value) {
setSaveBehavior(value);
return this;
}
/**
* @return the currently-configured consistent read behavior
*/
public ConsistentReads getConsistentReads() {
return consistentReads;
}
/**
* @param value the new consistent read behavior
*/
public void setConsistentReads(ConsistentReads value) {
consistentReads = value;
}
/**
* @param value the new consistent read behavior
* @return this builder
*/
public Builder withConsistentReads(ConsistentReads value) {
setConsistentReads(value);
return this;
}
/**
* @return the current table name override
*/
public TableNameOverride getTableNameOverride() {
return tableNameOverride;
}
/**
* @param value the new table name override
*/
public void setTableNameOverride(TableNameOverride value) {
tableNameOverride = value;
}
/**
* @param value the new table name override
* @return this builder
*/
public Builder withTableNameOverride(TableNameOverride value) {
setTableNameOverride(value);
return this;
}
/**
* @return the current table name resolver
*/
public TableNameResolver getTableNameResolver() {
return tableNameResolver;
}
/**
* @param value the new table name resolver
*/
public void setTableNameResolver(TableNameResolver value) {
tableNameResolver = value;
}
/**
* @param value the new table name resolver
* @return this builder
*/
public Builder withTableNameResolver(TableNameResolver value) {
setTableNameResolver(value);
return this;
}
/**
* @return the current object table name resolver
*/
public ObjectTableNameResolver getObjectTableNameResolver() {
return objectTableNameResolver;
}
/**
* @param value the new object table name resolver
*/
public void setObjectTableNameResolver(ObjectTableNameResolver value) {
objectTableNameResolver = value;
}
/**
* @param value the new object table name resolver
* @return this builder
*/
public Builder withObjectTableNameResolver(ObjectTableNameResolver value) {
setObjectTableNameResolver(value);
return this;
}
/**
* @return the currently-configured pagination loading strategy
*/
public PaginationLoadingStrategy getPaginationLoadingStrategy() {
return paginationLoadingStrategy;
}
/**
* @param value the new pagination loading strategy
*/
public void setPaginationLoadingStrategy(
PaginationLoadingStrategy value) {
paginationLoadingStrategy = value;
}
/**
* @param value the new pagination loading strategy
* @return this builder
*/
public Builder withPaginationLoadingStrategy(
PaginationLoadingStrategy value) {
setPaginationLoadingStrategy(value);
return this;
}
/**
* @return the currently-configured request metric collector
*/
public RequestMetricCollector getRequestMetricCollector() {
return requestMetricCollector;
}
/**
* @param value the new request metric collector
*/
public void setRequestMetricCollector(RequestMetricCollector value) {
requestMetricCollector = value;
}
/**
* @param value the new request metric collector
* @return this builder
*/
public Builder withRequestMetricCollector(RequestMetricCollector value) {
setRequestMetricCollector(value);
return this;
}
/**
* @return the current conversion schema
*/
public ConversionSchema getConversionSchema() {
return conversionSchema;
}
/**
* @param value the new conversion schema
*/
public void setConversionSchema(ConversionSchema value) {
conversionSchema = value;
}
/**
* @param value the new conversion schema
* @return this builder
*/
public Builder withConversionSchema(ConversionSchema value) {
setConversionSchema(value);
return this;
}
/**
* Builds a new {@code DynamoDBMapperConfig} object.
*
* @return the new, immutable config object
*/
public DynamoDBMapperConfig build() {
return new DynamoDBMapperConfig(
saveBehavior,
consistentReads,
tableNameOverride,
tableNameResolver,
objectTableNameResolver,
paginationLoadingStrategy,
requestMetricCollector,
conversionSchema);
}
}
/**
* Enumeration of behaviors for the save operation.
*/
public static enum SaveBehavior {
/**
* UPDATE will not affect unmodeled attributes on a save operation and a
* null value for the modeled attribute will remove it from that item in
* DynamoDB.
* <p>
* Because of the limitation of updateItem request, the implementation
* of UPDATE will send a putItem request when a key-only object is being
* saved, and it will send another updateItem request if the given
* key(s) already exists in the table.
* <p>
* By default, the mapper uses UPDATE.
*/
UPDATE,
/**
* UPDATE_SKIP_NULL_ATTRIBUTES is similar to UPDATE, except that it
* ignores any null value attribute(s) and will NOT remove them from
* that item in DynamoDB. It also guarantees to send only one single
* updateItem request, no matter the object is key-only or not.
*/
UPDATE_SKIP_NULL_ATTRIBUTES,
/**
* CLOBBER will clear and replace all attributes, included unmodeled
* ones, (delete and recreate) on save. Versioned field constraints will
* also be disregarded.
*/
CLOBBER,
/**
* APPEND_SET treats scalar attributes (String, Number, Binary) the same
* as UPDATE_SKIP_NULL_ATTRIBUTES does. However, for set attributes, it
* will append to the existing attribute value, instead of overriding
* it. Caller needs to make sure that the modeled attribute type matches
* the existing set type, otherwise it would result in a service
* exception.
*/
APPEND_SET
};
/**
* Enumeration of consistent read behavior.
* <p>
* CONSISTENT uses consistent reads, EVENTUAL does not. Consistent reads
* have implications for performance and billing; see the service
* documentation for details.
* <p>
* By default, the mapper uses eventual consistency.
*/
public static enum ConsistentReads {
CONSISTENT,
EVENTUAL
};
/**
* Enumeration of pagination loading strategy.
*/
public static enum PaginationLoadingStrategy {
/**
* Paginated list is lazily loaded when possible, and all loaded results
* are kept in the memory.
* <p>
* By default, the mapper uses LAZY_LOADING.
*/
LAZY_LOADING,
/**
* Only supports using iterator to read from the paginated list. All
* other list operations will return UnsupportedOperationException
* immediately. During the iteration, the list will clear all the
* previous results before loading the next page, so that the list will
* keep at most one page of the loaded results in memory. This also
* means the list could only be iterated once.
* <p>
* Use this configuration to reduce the memory overhead when handling
* large DynamoDB items.
*/
ITERATION_ONLY,
/**
* Paginated list will eagerly load all the paginated results from
* DynamoDB as soon as the list is initialized.
*/
EAGER_LOADING
}
/**
* Allows overriding the table name declared on a domain class by the
* {@link DynamoDBTable} annotation.
*/
public static final class TableNameOverride {
private final String tableNameOverride;
private final String tableNamePrefix;
/**
* Returns a new {@link TableNameOverride} object that will prepend the
* given string to every table name.
*/
public static TableNameOverride withTableNamePrefix(
String tableNamePrefix) {
return new TableNameOverride(null, tableNamePrefix);
}
/**
* Returns a new {@link TableNameOverride} object that will replace
* every table name in requests with the given string.
*/
public static TableNameOverride withTableNameReplacement(
String tableNameReplacement) {
return new TableNameOverride(tableNameReplacement, null);
}
private TableNameOverride(
String tableNameOverride,
String tableNamePrefix) {
this.tableNameOverride = tableNameOverride;
this.tableNamePrefix = tableNamePrefix;
}
/**
* @see TableNameOverride#withTableNameReplacement(String)
*/
public TableNameOverride(String tableNameOverride) {
this(tableNameOverride, null);
}
/**
* Returns the table name to use for all requests. Exclusive with
* {@link TableNameOverride#getTableNamePrefix()}
*
* @see DynamoDBMapperConfig#getTableNameOverride()
*/
public String getTableName() {
return tableNameOverride;
}
/**
* Returns the table name prefix to prepend the table name for all
* requests. Exclusive with {@link TableNameOverride#getTableName()}
*
* @see DynamoDBMapperConfig#getTableNameOverride()
*/
public String getTableNamePrefix() {
return tableNamePrefix;
}
}
/**
* Interface for a strategy used to determine the table name of an object
* based on it's class. This resolver is used when an object isn't available
* such as in {@link DynamoDBMapper#query(Class, DynamoDBQueryExpression)}
*
* @see ObjectTableNameResolver
* @author Raniz
*/
public static interface TableNameResolver {
/**
* Get the table name for a class. This method is used when an object is
* not available such as when creating requests for scan or query
* operations.
*
* @param clazz The class to get the table name for
* @param config The {@link DynamoDBMapperConfig}
* @return The table name to use for instances of clazz
*/
public String getTableName(Class<?> clazz, DynamoDBMapperConfig config);
}
/**
* Interface for a strategy used to determine the table name of an object
* based on it's class. This resolver is used when an object is available
* such as in {@link DynamoDBMapper#batchLoad(java.util.List)}. If no table
* name resolver for objects is set, {@link DynamoDBMapper} reverts to using
* the {@link TableNameResolver} on each object's class.
*
* @see TableNameResolver
* @author Raniz
*/
public static interface ObjectTableNameResolver {
/**
* Get the table name for an object.
*
* @param object The object to get the table name for
* @param config The {@link DynamoDBMapperConfig}
* @return The table name to use for object
*/
public String getTableName(Object object, DynamoDBMapperConfig config);
}
/**
* Default implementation of {@link TableNameResolver} that mimics the
* behavior of DynamoDBMapper before the addition of
* {@link TableNameResolver}.
*
* @author Raniz
*/
public static class DefaultTableNameResolver implements TableNameResolver {
public static final DefaultTableNameResolver INSTANCE = new DefaultTableNameResolver();
private final DynamoDBReflector reflector = new DynamoDBReflector();
@Override
public String getTableName(Class<?> clazz, DynamoDBMapperConfig config) {
DynamoDBTable table = reflector.getTable(clazz);
String tableName = table.tableName();
if (config.getTableNameOverride() != null) {
if (config.getTableNameOverride().getTableName() != null) {
tableName = config.getTableNameOverride().getTableName();
} else {
tableName = config.getTableNameOverride().getTableNamePrefix()
+ tableName;
}
}
return tableName;
}
}
private final SaveBehavior saveBehavior;
private final ConsistentReads consistentReads;
private final TableNameOverride tableNameOverride;
private final TableNameResolver tableNameResolver;
private final ObjectTableNameResolver objectTableNameResolver;
private final PaginationLoadingStrategy paginationLoadingStrategy;
private final RequestMetricCollector requestMetricCollector;
private final ConversionSchema conversionSchema;
/**
* Legacy constructor, using default PaginationLoadingStrategy
*
* @deprecated in favor of the fluent {@link Builder}
**/
@Deprecated
public DynamoDBMapperConfig(
SaveBehavior saveBehavior,
ConsistentReads consistentReads,
TableNameOverride tableNameOverride) {
this(saveBehavior, consistentReads, tableNameOverride, null, null);
}
/**
* Constructs a new configuration object with the save behavior, consistent
* read behavior, and table name override given.
*
* @param saveBehavior The {@link SaveBehavior} to use, or null for default.
* @param consistentReads The {@link ConsistentReads} to use, or null for
* default.
* @param tableNameOverride An override for the table name, or null for no
* override.
* @param paginationLoadingStrategy The pagination loading strategy, or null
* for default.
* @deprecated in favor of the fluent {@code Builder}
*/
@Deprecated
public DynamoDBMapperConfig(
SaveBehavior saveBehavior,
ConsistentReads consistentReads,
TableNameOverride tableNameOverride,
PaginationLoadingStrategy paginationLoadingStrategy) {
this(saveBehavior, consistentReads, tableNameOverride,
paginationLoadingStrategy, null);
}
/**
* Constructs a new configuration object with the save behavior, consistent
* read behavior, and table name override given.
*
* @param saveBehavior The {@link SaveBehavior} to use, or null for default.
* @param consistentReads The {@link ConsistentReads} to use, or null for
* default.
* @param tableNameOverride An override for the table name, or null for no
* override.
* @param paginationLoadingStrategy The pagination loading strategy, or null
* for default.
* @param requestMetricCollector optional request metric collector
* @deprecated in favor of the fluent {@code Builder}
*/
@Deprecated
public DynamoDBMapperConfig(
SaveBehavior saveBehavior,
ConsistentReads consistentReads,
TableNameOverride tableNameOverride,
PaginationLoadingStrategy paginationLoadingStrategy,
RequestMetricCollector requestMetricCollector) {
this(saveBehavior,
consistentReads,
tableNameOverride,
null,
null,
paginationLoadingStrategy,
requestMetricCollector,
ConversionSchemas.DEFAULT);
}
private DynamoDBMapperConfig(
SaveBehavior saveBehavior,
ConsistentReads consistentReads,
TableNameOverride tableNameOverride,
TableNameResolver tableNameResolver,
ObjectTableNameResolver objectTableNameResolver,
PaginationLoadingStrategy paginationLoadingStrategy,
RequestMetricCollector requestMetricCollector,
ConversionSchema conversionSchema) {
this.saveBehavior = saveBehavior;
this.consistentReads = consistentReads;
this.tableNameOverride = tableNameOverride;
this.tableNameResolver = tableNameResolver;
this.objectTableNameResolver = objectTableNameResolver;
this.paginationLoadingStrategy = paginationLoadingStrategy;
this.requestMetricCollector = requestMetricCollector;
this.conversionSchema = conversionSchema;
}
/**
* Constructs a new configuration object with the save behavior given.
*/
public DynamoDBMapperConfig(SaveBehavior saveBehavior) {
this(saveBehavior, null, null, null, null, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the consistent read behavior
* given.
*/
public DynamoDBMapperConfig(ConsistentReads consistentReads) {
this(null, consistentReads, null, null, null, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the table name override given.
*/
public DynamoDBMapperConfig(TableNameOverride tableNameOverride) {
this(null, null, tableNameOverride, null, null, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the table name resolver
* strategy given.
*/
public DynamoDBMapperConfig(TableNameResolver tableNameResolver) {
this(null, null, null, tableNameResolver, null, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the object table name resolver
* strategy given.
*/
public DynamoDBMapperConfig(ObjectTableNameResolver objectTableNameResolver) {
this(null, null, null, null, objectTableNameResolver, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the table name resolver
* strategies given.
*/
public DynamoDBMapperConfig(TableNameResolver tableNameResolver,
ObjectTableNameResolver objectTableNameResolver) {
this(null, null, null, tableNameResolver, objectTableNameResolver, null, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the pagination loading
* strategy given.
*/
public DynamoDBMapperConfig(
PaginationLoadingStrategy paginationLoadingStrategy) {
this(null, null, null, null, null, paginationLoadingStrategy, null,
ConversionSchemas.DEFAULT);
}
/**
* Constructs a new configuration object with the conversion schema given.
*/
public DynamoDBMapperConfig(ConversionSchema conversionSchema) {
this(null, null, null, null, null, null, null, conversionSchema);
}
/**
* Constructs a new configuration object from two others: a set of defaults
* and a set of overrides. Any non-null overrides will be applied to the
* defaults.
* <p>
* Used internally to merge the {@link DynamoDBMapperConfig} provided at
* construction with an overriding object for a particular operation.
*
* @param defaults The default mapper configuration values.
* @param overrides The overridden mapper configuration values. Any non-null
* config settings will be applied to the returned object.
*/
public DynamoDBMapperConfig(
DynamoDBMapperConfig defaults,
DynamoDBMapperConfig overrides) {
if (overrides == null) {
this.saveBehavior = defaults.getSaveBehavior();
this.consistentReads = defaults.getConsistentReads();
this.tableNameOverride = defaults.getTableNameOverride();
this.tableNameResolver = defaults.getTableNameResolver();
this.objectTableNameResolver = defaults.getObjectTableNameResolver();
this.paginationLoadingStrategy =
defaults.getPaginationLoadingStrategy();
this.requestMetricCollector = defaults.getRequestMetricCollector();
this.conversionSchema = defaults.getConversionSchema();
} else {
this.saveBehavior = (overrides.getSaveBehavior() == null)
? defaults.getSaveBehavior()
: overrides.getSaveBehavior();
this.consistentReads = (overrides.getConsistentReads() == null)
? defaults.getConsistentReads()
: overrides.getConsistentReads();
this.tableNameOverride = (overrides.getTableNameOverride() == null)
? defaults.getTableNameOverride()
: overrides.getTableNameOverride();
this.tableNameResolver = (overrides.getTableNameResolver() == null)
? defaults.getTableNameResolver()
: overrides.getTableNameResolver();
this.objectTableNameResolver = (overrides.getObjectTableNameResolver() == null)
? defaults.getObjectTableNameResolver()
: overrides.getObjectTableNameResolver();
this.paginationLoadingStrategy =
(overrides.getPaginationLoadingStrategy() == null)
? defaults.getPaginationLoadingStrategy()
: overrides.getPaginationLoadingStrategy();
this.requestMetricCollector =
(overrides.getRequestMetricCollector() == null)
? defaults.getRequestMetricCollector()
: overrides.getRequestMetricCollector();
this.conversionSchema = (overrides.getConversionSchema() == null)
? defaults.getConversionSchema()
: overrides.getConversionSchema();
}
}
/**
* Returns the save behavior for this configuration.
*/
public SaveBehavior getSaveBehavior() {
return saveBehavior;
}
/**
* Returns the consistent read behavior for this configuration.
*/
public ConsistentReads getConsistentReads() {
return consistentReads;
}
/**
* Returns the table name override for this configuration. This value will
* override the table name specified in a {@link DynamoDBTable} annotation,
* either by replacing the table name entirely or else by pre-pending a
* string to each table name. This is useful for partitioning data in
* multiple tables at runtime.
*
* @see TableNameOverride#withTableNamePrefix(String)
* @see TableNameOverride#withTableNameReplacement(String)
*/
public TableNameOverride getTableNameOverride() {
return tableNameOverride;
}
/**
* Returns the table name resolver for this configuration. This value will
* be used to determine the table name for classes. It can be used for more
* powerful customization of table name than is possible using only
* {@link TableNameOverride}.
*
* @see TableNameResolver#getTableName(Class, DynamoDBMapperConfig)
*/
public TableNameResolver getTableNameResolver() {
return tableNameResolver;
}
/**
* Returns the object table name resolver for this configuration. This value
* will be used to determine the table name for objects. It can be used for
* more powerful customization of table name than is possible using only
* {@link TableNameOverride}.
*
* @see ObjectTableNameResolver#getTableName(Object, DynamoDBMapperConfig)
*/
public ObjectTableNameResolver getObjectTableNameResolver() {
return objectTableNameResolver;
}
/**
* Returns the pagination loading strategy for this configuration.
*/
public PaginationLoadingStrategy getPaginationLoadingStrategy() {
return paginationLoadingStrategy;
}
/**
* Returns the request metric collector or null if not specified.
*/
public RequestMetricCollector getRequestMetricCollector() {
return requestMetricCollector;
}
/**
* @return the conversion schema for this config object
*/
public ConversionSchema getConversionSchema() {
return conversionSchema;
}
/**
* Default configuration uses UPDATE behavior for saves and EVENTUALly
* consistent reads, with no table name override and lazy-loading strategy.
*/
public static final DynamoDBMapperConfig DEFAULT = new DynamoDBMapperConfig(
SaveBehavior.UPDATE,
ConsistentReads.EVENTUAL,
null, // TableNameOverride
null, // TableNameResolver
null, // ObjectTableNameResolver
PaginationLoadingStrategy.LAZY_LOADING,
null, // RequestMetricCollector
ConversionSchemas.DEFAULT);
}