com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper Maven / Gradle / Ivy
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/*
* Copyright 2011-2014 Amazon Technologies, 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://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.services.dynamodbv2.datamodeling;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.AmazonWebServiceRequest;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.retry.RetryUtils;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.ConsistentReads;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.PaginationLoadingStrategy;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.SaveBehavior;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTableSchemaParser.TableIndexesInfo;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.AttributeValueUpdate;
import com.amazonaws.services.dynamodbv2.model.BatchGetItemRequest;
import com.amazonaws.services.dynamodbv2.model.BatchGetItemResult;
import com.amazonaws.services.dynamodbv2.model.BatchWriteItemRequest;
import com.amazonaws.services.dynamodbv2.model.BatchWriteItemResult;
import com.amazonaws.services.dynamodbv2.model.ComparisonOperator;
import com.amazonaws.services.dynamodbv2.model.Condition;
import com.amazonaws.services.dynamodbv2.model.ConditionalCheckFailedException;
import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
import com.amazonaws.services.dynamodbv2.model.DeleteItemRequest;
import com.amazonaws.services.dynamodbv2.model.DeleteRequest;
import com.amazonaws.services.dynamodbv2.model.ExpectedAttributeValue;
import com.amazonaws.services.dynamodbv2.model.GetItemRequest;
import com.amazonaws.services.dynamodbv2.model.GetItemResult;
import com.amazonaws.services.dynamodbv2.model.KeysAndAttributes;
import com.amazonaws.services.dynamodbv2.model.PutItemRequest;
import com.amazonaws.services.dynamodbv2.model.PutRequest;
import com.amazonaws.services.dynamodbv2.model.QueryRequest;
import com.amazonaws.services.dynamodbv2.model.QueryResult;
import com.amazonaws.services.dynamodbv2.model.ScanRequest;
import com.amazonaws.services.dynamodbv2.model.ScanResult;
import com.amazonaws.services.dynamodbv2.model.Select;
import com.amazonaws.services.dynamodbv2.model.UpdateItemRequest;
import com.amazonaws.services.dynamodbv2.model.WriteRequest;
import com.amazonaws.services.s3.model.Region;
import com.amazonaws.util.VersionInfoUtils;
/**
* Object mapper for domain-object interaction with DynamoDB.
*
* To use, define a domain class that represents an item in a DynamoDB table and
* annotate it with the annotations found in the
* com.amazonaws.services.dynamodbv2.datamodeling package. In order to allow the
* mapper to correctly persist the data, each modeled property in the domain
* class should be accessible via getter and setter methods, and each property
* annotation should be either applied to the getter method or the class field.
* A minimal example using getter annotations:
*
*
* @DynamoDBTable(tableName = "TestTable")
* public class TestClass {
*
* private Long key;
* private double rangeKey;
* private Long version;
*
* private Set<Integer> integerSetAttribute;
*
* @DynamoDBHashKey
* public Long getKey() {
* return key;
* }
*
* public void setKey(Long key) {
* this.key = key;
* }
*
* @DynamoDBRangeKey
* public double getRangeKey() {
* return rangeKey;
* }
*
* public void setRangeKey(double rangeKey) {
* this.rangeKey = rangeKey;
* }
*
* @DynamoDBAttribute(attributeName = "integerSetAttribute")
* public Set<Integer> getIntegerAttribute() {
* return integerSetAttribute;
* }
*
* public void setIntegerAttribute(Set<Integer> integerAttribute) {
* this.integerSetAttribute = integerAttribute;
* }
*
* @DynamoDBVersionAttribute
* public Long getVersion() {
* return version;
* }
*
* public void setVersion(Long version) {
* this.version = version;
* }
* }
*
*
* Save instances of annotated classes to DynamoDB, retrieve them, and delete
* them using the {@link DynamoDBMapper} class, as in the following example.
*
*
* DynamoDBMapper mapper = new DynamoDBMapper(dynamoDBClient);
* Long hashKey = 105L;
* double rangeKey = 1.0d;
* TestClass obj = mapper.load(TestClass.class, hashKey, rangeKey);
* obj.getIntegerAttribute().add(42);
* mapper.save(obj);
* mapper.delete(obj);
*
*
* When using the save, load, and delete methods, {@link DynamoDBMapper} will
* throw {@link DynamoDBMappingException}s to indicate that domain classes are
* incorrectly annotated or otherwise incompatible with this class. Service
* exceptions will always be propagated as {@link AmazonClientException}, and
* DynamoDB-specific subclasses such as {@link ConditionalCheckFailedException}
* will be used when possible.
*
* This class is thread-safe and can be shared between threads. It's also very
* lightweight, so it doesn't need to be.
*
* @see DynamoDBTable
* @see DynamoDBHashKey
* @see DynamoDBRangeKey
* @see DynamoDBAutoGeneratedKey
* @see DynamoDBAttribute
* @see DynamoDBVersionAttribute
* @see DynamoDBIgnore
* @see DynamoDBMarshalling
* @see DynamoDBMapperConfig
*/
public class DynamoDBMapper {
private final S3ClientCache s3cc;
private final AmazonDynamoDB db;
private final DynamoDBMapperConfig config;
private final DynamoDBReflector reflector = new DynamoDBReflector();
private final DynamoDBTableSchemaParser schemaParser = new DynamoDBTableSchemaParser();
private final AttributeTransformer transformer;
/** The max back off time for batch write */
static final long MAX_BACKOFF_IN_MILLISECONDS = 1000 * 3;
/**
* This retry count is applicable only when every batch get item request
* results in no data retrieved from server and the un processed keys is
* same as request items
*/
static final int BATCH_GET_MAX_RETRY_COUNT_ALL_KEYS = 5;
/**
* User agent for requests made using the {@link DynamoDBMapper}.
*/
private static final String USER_AGENT = DynamoDBMapper.class.getName() + "/" + VersionInfoUtils.getVersion();
private static final String NO_RANGE_KEY = new String();
private static final Log log = LogFactory.getLog(DynamoDBMapper.class);
/**
* Constructs a new mapper with the service object given, using the default
* configuration.
*
* @param dynamoDB
* The service object to use for all service calls.
* @see DynamoDBMapperConfig#DEFAULT
*/
public DynamoDBMapper(final AmazonDynamoDB dynamoDB) {
this(dynamoDB, DynamoDBMapperConfig.DEFAULT, null, null);
}
/**
* Constructs a new mapper with the service object and configuration given.
*
* @param dynamoDB
* The service object to use for all service calls.
* @param config
* The default configuration to use for all service calls. It can
* be overridden on a per-operation basis.
*/
public DynamoDBMapper(
final AmazonDynamoDB dynamoDB,
final DynamoDBMapperConfig config) {
this(dynamoDB, config, null, null);
}
/**
* Constructs a new mapper with the service object and S3 client cache
* given, using the default configuration.
*
* @param ddb
* The service object to use for all service calls.
* @param s3CredentialProvider
* The credentials provider for accessing S3.
* Relevant only if {@link S3Link} is involved.
* @see DynamoDBMapperConfig#DEFAULT
*/
public DynamoDBMapper(
final AmazonDynamoDB ddb,
final AWSCredentialsProvider s3CredentialProvider) {
this(ddb, DynamoDBMapperConfig.DEFAULT, s3CredentialProvider);
}
/**
* Constructs a new mapper with the given service object, configuration,
* and transform hook.
*
* @param dynamoDB
* the service object to use for all service calls
* @param config
* the default configuration to use for all service calls. It
* can be overridden on a per-operation basis
* @param transformer
* The custom attribute transformer to invoke when serializing or
* deserializing an object.
*/
public DynamoDBMapper(
final AmazonDynamoDB dynamoDB,
final DynamoDBMapperConfig config,
final AttributeTransformer transformer) {
this(dynamoDB, config, transformer, null);
}
/**
* Constructs a new mapper with the service object, configuration, and S3
* client cache given.
*
* @param dynamoDB
* The service object to use for all service calls.
* @param config
* The default configuration to use for all service calls. It can
* be overridden on a per-operation basis.
* @param s3CredentialProvider
* The credentials provider for accessing S3.
* Relevant only if {@link S3Link} is involved.
*/
public DynamoDBMapper(
final AmazonDynamoDB dynamoDB,
final DynamoDBMapperConfig config,
final AWSCredentialsProvider s3CredentialProvider) {
this(dynamoDB, config, null, validate(s3CredentialProvider));
}
/**
* Throws an exception if the given credentials provider is {@code null}.
*/
private static AWSCredentialsProvider validate(
final AWSCredentialsProvider provider) {
if (provider == null) {
throw new IllegalArgumentException(
"s3 credentials provider must not be null");
}
return provider;
}
/**
* Constructor with all parameters.
*
* @param dynamoDB
* The service object to use for all service calls.
* @param config
* The default configuration to use for all service calls. It can
* be overridden on a per-operation basis.
* @param transformer
* The custom attribute transformer to invoke when serializing or
* deserializing an object.
* @param s3CredentialProvider
* The credentials provider for accessing S3.
* Relevant only if {@link S3Link} is involved.
*/
public DynamoDBMapper(
final AmazonDynamoDB dynamoDB,
final DynamoDBMapperConfig config,
final AttributeTransformer transformer,
final AWSCredentialsProvider s3CredentialsProvider) {
this.db = dynamoDB;
this.config = config;
this.transformer = transformer;
if (s3CredentialsProvider == null) {
this.s3cc = null;
} else {
this.s3cc = new S3ClientCache(s3CredentialsProvider.getCredentials());
}
}
/**
* Loads an object with the hash key given and a configuration override.
* This configuration overrides the default provided at object construction.
*
* @see DynamoDBMapper#load(Class, Object, Object, DynamoDBMapperConfig)
*/
public T load(Class clazz, Object hashKey, DynamoDBMapperConfig config) {
return load(clazz, hashKey, null, config);
}
/**
* Loads an object with the hash key given, using the default configuration.
*
* @see DynamoDBMapper#load(Class, Object, Object, DynamoDBMapperConfig)
*/
public T load(Class clazz, Object hashKey) {
return load(clazz, hashKey, null, config);
}
/**
* Loads an object with a hash and range key, using the default
* configuration.
*
* @see DynamoDBMapper#load(Class, Object, Object, DynamoDBMapperConfig)
*/
public T load(Class clazz, Object hashKey, Object rangeKey) {
return load(clazz, hashKey, rangeKey, config);
}
/**
* Returns an object whose keys match those of the prototype key object given,
* or null if no such item exists.
*
* @param keyObject
* An object of the class to load with the keys values to match.
*
* @see DynamoDBMapper#load(Object, DynamoDBMapperConfig)
*/
public T load(T keyObject) {
return load(keyObject, this.config);
}
/**
* Returns an object whose keys match those of the prototype key object given,
* or null if no such item exists.
*
* @param keyObject
* An object of the class to load with the keys values to match.
* @param config
* Configuration for the service call to retrieve the object from
* DynamoDB. This configuration overrides the default given at
* construction.
*/
public T load(T keyObject, DynamoDBMapperConfig config) {
@SuppressWarnings("unchecked")
Class clazz = (Class) keyObject.getClass();
config = mergeConfig(config);
String tableName = getTableName(clazz, config);
GetItemRequest rq = new GetItemRequest()
.withRequestMetricCollector(config.getRequestMetricCollector());
Map key = getKey(keyObject, clazz);
rq.setKey(key);
rq.setTableName(tableName);
rq.setConsistentRead(config.getConsistentReads() == ConsistentReads.CONSISTENT);
GetItemResult item = db.getItem(applyUserAgent(rq));
Map itemAttributes = item.getItem();
if ( itemAttributes == null ) {
return null;
}
T object = marshalIntoObject(toParameters(itemAttributes, clazz, config));
return object;
}
/**
* Returns a key map for the key object given.
*
* @param keyObject
* The key object, corresponding to an item in a dynamo table.
*/
@SuppressWarnings("unchecked")
private Map getKey(T keyObject) {
return getKey(keyObject, (Class)keyObject.getClass());
}
private Map getKey(T keyObject, Class clazz) {
Map key = new HashMap();
for (Method keyGetter : reflector.getPrimaryKeyGetters(clazz)) {
Object getterResult = safeInvoke(keyGetter, keyObject);
AttributeValue keyAttributeValue = getSimpleAttributeValue(keyGetter, getterResult);
if (keyAttributeValue == null) {
throw new DynamoDBMappingException("Null key found for " + keyGetter);
}
key.put(reflector.getAttributeName(keyGetter), keyAttributeValue);
}
if ( key.isEmpty() ) {
throw new DynamoDBMappingException("Class must be annotated with " + DynamoDBHashKey.class + " and "
+ DynamoDBRangeKey.class);
}
return key;
}
/**
* Returns an object with the given hash key, or null if no such object
* exists.
*
* @param clazz
* The class to load, corresponding to a DynamoDB table.
* @param hashKey
* The key of the object.
* @param rangeKey
* The range key of the object, or null for tables without a
* range key.
* @param config
* Configuration for the service call to retrieve the object from
* DynamoDB. This configuration overrides the default given at
* construction.
*/
public T load(Class clazz, Object hashKey, Object rangeKey, DynamoDBMapperConfig config) {
config = mergeConfig(config);
T keyObject = createKeyObject(clazz, hashKey, rangeKey);
return load(keyObject, config);
}
/**
* Creates a key prototype object for the class given with the single hash and range key given.
*/
private T createKeyObject(Class clazz, Object hashKey, Object rangeKey) {
T keyObject = null;
try {
keyObject = clazz.newInstance();
} catch ( Exception e ) {
throw new DynamoDBMappingException("Failed to instantiate class", e);
}
boolean seenHashKey = false;
boolean seenRangeKey = false;
for ( Method getter : reflector.getPrimaryKeyGetters(clazz) ) {
if ( ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBHashKey.class) ) {
if ( seenHashKey ) {
throw new DynamoDBMappingException("Found more than one method annotated with "
+ DynamoDBHashKey.class + " for class " + clazz
+ ". Use load(Object) for tables with more than a single hash and range key.");
}
seenHashKey = true;
safeInvoke(reflector.getSetter(getter), keyObject, hashKey);
} else if ( ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBRangeKey.class) ) {
if ( seenRangeKey ) {
throw new DynamoDBMappingException("Found more than one method annotated with "
+ DynamoDBRangeKey.class + " for class " + clazz
+ ". Use load(Object) for tables with more than a single hash and range key.");
}
seenRangeKey = true;
safeInvoke(reflector.getSetter(getter), keyObject, rangeKey);
}
}
if ( !seenHashKey ) {
throw new DynamoDBMappingException("No method annotated with " + DynamoDBHashKey.class + " for class "
+ clazz + ".");
} else if ( rangeKey != null && !seenRangeKey ) {
throw new DynamoDBMappingException("No method annotated with " + DynamoDBRangeKey.class + " for class "
+ clazz + ".");
}
return keyObject;
}
/**
* Returns a map of attribute name to EQ condition for the key prototype
* object given. This method considers attributes annotated with either
* {@link DynamoDBHashKey} or {@link DynamoDBIndexHashKey}.
*
* @param obj
* The prototype object that includes the hash key value.
* @return A map of hash key attribute name to EQ condition for the key
* prototype object, or an empty map if obj is null.
*/
private Map getHashKeyEqualsConditions(Object obj) {
Map conditions = new HashMap();
if (obj != null) {
for ( Method getter : reflector.getRelevantGetters(obj.getClass()) ) {
if ( ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBHashKey.class)
|| ReflectionUtils.getterOrFieldHasAnnotation(getter, DynamoDBIndexHashKey.class) ) {
Object getterReturnResult = safeInvoke(getter, obj, (Object[])null);
if (getterReturnResult != null) {
conditions.put(
reflector.getAttributeName(getter),
new Condition().withComparisonOperator(ComparisonOperator.EQ).withAttributeValueList(
getSimpleAttributeValue(getter, getterReturnResult)));
}
}
}
}
return conditions;
}
/**
* Returns the table name for the class given.
*/
protected final String getTableName(final Class clazz,
final DynamoDBMapperConfig config) {
return getTableName(clazz, config, reflector);
}
static String getTableName(final Class clazz,
final DynamoDBMapperConfig config,
final DynamoDBReflector reflector) {
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;
}
/**
* A replacement for {@link #marshallIntoObject(Class, Map)} that takes
* extra parameters to tunnel through to {@code privateMarshalIntoObject}.
*
* Once {@code marshallIntoObject} is removed, this method will directly
* call {@code privateMarshalIntoObject}.
*/
private T marshalIntoObject(
final AttributeTransformer.Parameters parameters
) {
return marshallIntoObject(
parameters.getModelClass(),
MapAnd.wrap(parameters.getAttributeValues(), parameters));
}
/**
* Creates and fills in the attributes on an instance of the class given
* with the attributes given.
*
* This is accomplished by looking for getter methods annotated with an
* appropriate annotation, then looking for matching attribute names in the
* item attribute map.
*
* This method has been marked deprecated because it does not allow
* load/query/scan to pass through their DynamoDBMapperConfig parameter,
* which is needed by some implementations of {@code AttributeTransformer}.
* In a future version of the SDK, load/query/scan will be changed to
* directly call privateMarshalIntoObject, and will no longer call this
* method.
*
* If you are extending DynamoDBMapper and overriding this method to
* customize how the mapper unmarshals POJOs from a raw DynamoDB item,
* please switch to using an AttributeTransformer (or open a GitHub
* issue if you need to fully control the unmarshalling process, and we'll
* figure out a better way to expose such a hook).
*
* If you're simply calling this method, it will continue to be available
* for the forseeable future - feel free to ignore the @Deprecated tag.
*
* @param clazz
* The class to instantiate and hydrate
* @param itemAttributes
* The set of item attributes, keyed by attribute name.
* @deprecated as an extension point for adding custom unmarshalling
*/
@Deprecated
public T marshallIntoObject(Class clazz, Map itemAttributes) {
if (itemAttributes instanceof MapAnd) {
@SuppressWarnings("unchecked")
AttributeTransformer.Parameters parameters =
((MapAnd>) itemAttributes)
.getExtra();
return privateMarshalIntoObject(parameters);
} else {
// Called via some unexpected external codepath; use the class-level
// config.
return privateMarshalIntoObject(
toParameters(itemAttributes, clazz, this.config));
}
}
/**
* The one true implementation of marshalIntoObject.
*/
private T privateMarshalIntoObject(
final AttributeTransformer.Parameters parameters) {
T toReturn = null;
try {
toReturn = parameters.getModelClass().newInstance();
} catch ( InstantiationException e ) {
throw new DynamoDBMappingException("Failed to instantiate new instance of class", e);
} catch ( IllegalAccessException e ) {
throw new DynamoDBMappingException("Failed to instantiate new instance of class", e);
}
if ( parameters.getAttributeValues() == null
|| parameters.getAttributeValues().isEmpty() ) {
return toReturn;
}
Map result = untransformAttributes(parameters);
for ( Method m : reflector.getRelevantGetters(parameters.getModelClass()) ) {
String attributeName = reflector.getAttributeName(m);
if ( result.containsKey(attributeName) ) {
setValue(toReturn, m, result.get(attributeName));
}
}
return toReturn;
}
/**
* Unmarshalls the list of item attributes into objects of type clazz.
*
* This method has been marked deprecated because it does not allow
* query/scan to pass through their DynamoDBMapperConfig parameter,
* which is needed by some implementations of {@code AttributeTransformer}.
* In a future version of the SDK, query/scan will be changed to directly
* call privateMarshalIntoObjects, and will no longer call this method.
*
* If you are extending DynamoDBMapper and overriding this method to
* customize how the mapper unmarshals POJOs from raw DynamoDB items,
* please switch to using an AttributeTransformer (or open a GitHub
* issue if you need to fully control the unmarshalling process, and we'll
* figure out a better way to expose such a hook).
*
* If you're simply calling this method, it will continue to be available
* for the forseeable future - feel free to ignore the @Deprecated tag.
*
* @see DynamoDBMapper#marshallIntoObject(Class, Map)
* @deprecated as an extension point for adding custom unmarshalling
*/
@Deprecated
public List marshallIntoObjects(Class clazz, List> itemAttributes) {
List result = new ArrayList(itemAttributes.size());
for (Map item : itemAttributes) {
result.add(marshallIntoObject(clazz, item));
}
return result;
}
/**
* A replacement for {@link #marshallIntoObjects(Class, List)} that takes
* an extra set of parameters to be tunneled through to
* {@code privateMarshalIntoObject} (if nothing along the way is
* overridden). It's package-private because some of the Paginated*List
* classes call back into it, but final because no one, even in this
* package, should ever override it.
*
* In the future, when the deprecated {@code marshallIntoObjects} is
* removed, this method will be changed to directly call
* {@code privateMarshalIntoObject}.
*/
final List marshalIntoObjects(
final List> parameters
) {
if (parameters.isEmpty()) {
return Collections.emptyList();
}
Class clazz = parameters.get(0).getModelClass();
List> list =
new ArrayList>(parameters.size());
for (AttributeTransformer.Parameters entry : parameters) {
list.add(MapAnd.wrap(entry.getAttributeValues(), entry));
}
return marshallIntoObjects(clazz, list);
}
/**
* Sets the value in the return object corresponding to the service result.
*/
private void setValue(final T toReturn, final Method getter, AttributeValue value) {
Method setter = reflector.getSetter(getter);
ArgumentUnmarshaller unmarhsaller = reflector.getArgumentUnmarshaller(toReturn, getter, setter, s3cc);
unmarhsaller.typeCheck(value, setter);
Object argument;
try {
argument = unmarhsaller.unmarshall(value);
} catch ( IllegalArgumentException e ) {
throw new DynamoDBMappingException("Couldn't unmarshall value " + value + " for " + setter, e);
} catch ( ParseException e ) {
throw new DynamoDBMappingException("Error attempting to parse date string " + value + " for "+ setter, e);
}
safeInvoke(setter, toReturn, argument);
}
/**
* Returns an {@link AttributeValue} corresponding to the getter and return
* result given, treating it as a non-versioned attribute.
*/
private AttributeValue getSimpleAttributeValue(final Method getter, final Object getterReturnResult) {
if ( getterReturnResult == null )
return null;
ArgumentMarshaller marshaller = reflector.getArgumentMarshaller(getter);
return marshaller.marshall(getterReturnResult);
}
/**
* Saves the object given into DynamoDB, using the default configuration.
*
* @see DynamoDBMapper#save(Object, DynamoDBSaveExpression, DynamoDBMapperConfig)
*/
public void save(T object) {
save(object, null, config);
}
/**
* Saves the object given into DynamoDB, using the default configuration and the specified saveExpression.
*
* @see DynamoDBMapper#save(Object, DynamoDBSaveExpression, DynamoDBMapperConfig)
*/
public void save(T object, DynamoDBSaveExpression saveExpression) {
save(object, saveExpression, config);
}
private boolean needAutoGenerateAssignableKey(Class clazz, Object object) {
Collection keyGetters = reflector.getPrimaryKeyGetters(clazz);
boolean forcePut = false;
/*
* Determine if there are any auto-assigned keys to assign. If so, force
* a put and assign the keys.
*/
boolean hashKeyGetterFound = false;
for ( Method method : keyGetters ) {
Object getterResult = safeInvoke(method, object);
if ( getterResult == null && reflector.isAssignableKey(method) ) {
forcePut = true;
}
if ( ReflectionUtils.getterOrFieldHasAnnotation(method, DynamoDBHashKey.class) ) {
hashKeyGetterFound = true;
}
}
if ( !hashKeyGetterFound ) {
throw new DynamoDBMappingException("No " + DynamoDBHashKey.class + " annotation found in class " + clazz);
}
return forcePut;
}
/**
* Saves the object given into DynamoDB, using the specified configuration.
*
* @see DynamoDBMapper#save(Object, DynamoDBSaveExpression, DynamoDBMapperConfig)
*/
public void save(T object, DynamoDBMapperConfig config) {
save(object, null, config);
}
/**
* Saves an item in DynamoDB. The service method used is determined by the
* {@link DynamoDBMapperConfig#getSaveBehavior()} value, to use either
* {@link AmazonDynamoDB#putItem(PutItemRequest)} or
* {@link AmazonDynamoDB#updateItem(UpdateItemRequest)}:
*
* - UPDATE (default) : 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. 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.
* - UPDATE_SKIP_NULL_ATTRIBUTES : 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.
* - CLOBBER : CLOBBER will clear and replace all attributes,
* included unmodeled ones, (delete and recreate) on save. Versioned field
* constraints will also be disregarded.
*
*
*
* Any options specified in the saveExpression parameter will be overlaid on
* any constraints due to versioned attributes.
*
* @param object
* The object to save into DynamoDB
* @param saveExpression
* The options to apply to this save request
* @param config
* The configuration to use, which overrides the default provided
* at object construction.
*
* @see DynamoDBMapperConfig.SaveBehavior
*/
public void save(T object, DynamoDBSaveExpression saveExpression, final DynamoDBMapperConfig config) {
final DynamoDBMapperConfig finalConfig = mergeConfig(config);
@SuppressWarnings("unchecked")
Class clazz = (Class) object.getClass();
String tableName = getTableName(clazz, finalConfig);
final Map userProvidedExpectedValues = (saveExpression == null) ? null : saveExpression.getExpected();
/*
* We force a putItem request instead of updateItem request either when
* CLOBBER is configured, or part of the primary key of the object needs
* to be auto-generated.
*/
boolean forcePut = (finalConfig.getSaveBehavior() == SaveBehavior.CLOBBER)
|| needAutoGenerateAssignableKey(clazz, object);
SaveObjectHandler saveObjectHandler;
if (forcePut) {
saveObjectHandler = this.new SaveObjectHandler(clazz, object,
tableName, finalConfig.getSaveBehavior(), userProvidedExpectedValues) {
@Override
protected void onKeyAttributeValue(String attributeName,
AttributeValue keyAttributeValue) {
/* Treat key values as common attribute value updates. */
getAttributeValueUpdates().put(attributeName,
new AttributeValueUpdate().withValue(keyAttributeValue)
.withAction("PUT"));
}
/* Use default implementation of onNonKeyAttribute(...) */
@Override
protected void onNullNonKeyAttribute(String attributeName) {
/* When doing a force put, we can safely ignore the null-valued attributes. */
return;
}
@Override
protected void executeLowLevelRequest(boolean onlyKeyAttributeSpecified) {
/* Send a putItem request */
Map attributeValues =
convertToItem(getAttributeValueUpdates());
attributeValues = transformAttributes(
toParameters(attributeValues, this.clazz, finalConfig));
PutItemRequest req = new PutItemRequest()
.withTableName(getTableName())
.withItem(attributeValues)
.withExpected(getExpectedAttributeValues())
.withRequestMetricCollector(
finalConfig.getRequestMetricCollector());
db.putItem(applyUserAgent(req));
}
};
} else {
saveObjectHandler = this.new SaveObjectHandler(clazz, object,
tableName, finalConfig.getSaveBehavior(), userProvidedExpectedValues) {
@Override
protected void onKeyAttributeValue(String attributeName,
AttributeValue keyAttributeValue) {
/* Put it in the key collection which is later used in the updateItem request. */
getKeyAttributeValues().put(attributeName, keyAttributeValue);
}
@Override
protected void onNonKeyAttribute(String attributeName,
AttributeValue currentValue) {
/* If it's a set attribute and the mapper is configured with APPEND_SET,
* we do an "ADD" update instead of the default "PUT".
*/
if (getLocalSaveBehavior() == SaveBehavior.APPEND_SET) {
if (currentValue.getBS() != null
|| currentValue.getNS() != null
|| currentValue.getSS() != null) {
getAttributeValueUpdates().put(
attributeName,
new AttributeValueUpdate().withValue(
currentValue).withAction("ADD"));
return;
}
}
/* Otherwise, we do the default "PUT" update. */
super.onNonKeyAttribute(attributeName, currentValue);
}
@Override
protected void onNullNonKeyAttribute(String attributeName) {
/*
* If UPDATE_SKIP_NULL_ATTRIBUTES or APPEND_SET is
* configured, we don't delete null value attributes.
*/
if (getLocalSaveBehavior() == SaveBehavior.UPDATE_SKIP_NULL_ATTRIBUTES
|| getLocalSaveBehavior() == SaveBehavior.APPEND_SET) {
return;
}
else {
/* Delete attributes that are set as null in the object. */
getAttributeValueUpdates()
.put(attributeName,
new AttributeValueUpdate()
.withAction("DELETE"));
}
}
@Override
protected void executeLowLevelRequest(boolean onlyKeyAttributeSpecified) {
/*
* Do a putItem when a key-only object is being saved with
* UPDATE configuration.
* Here we only need to consider UPDATE configuration, since
* only UPDATE could cause the problematic situation of
* updating an existing primary key with "DELETE" action on
* non-key attributes. See the javadoc of keyOnlyPut(...)
* for more detail.
*/
boolean doUpdateItem = true;
if (onlyKeyAttributeSpecified && getLocalSaveBehavior() == SaveBehavior.UPDATE) {
doUpdateItem = false;
try {
keyOnlyPut(this.clazz, this.object, getTableName(),
reflector.getPrimaryHashKeyGetter(this.clazz),
reflector.getPrimaryRangeKeyGetter(this.clazz),
userProvidedExpectedValues,
finalConfig);
} catch (AmazonServiceException ase) {
if (ase.getErrorCode().equals(
"ConditionalCheckFailedException")) {
/*
* If another item with the given keys is found
* in the table, we follow up an updateItem
* request.
*/
doUpdateItem = true;
} else {
throw ase;
}
}
}
if ( doUpdateItem ) {
/* Send an updateItem request. */
UpdateItemRequest req = new UpdateItemRequest()
.withTableName(getTableName())
.withKey(getKeyAttributeValues())
.withAttributeUpdates(
transformAttributeUpdates(this.clazz,
getKeyAttributeValues(),
getAttributeValueUpdates(),
finalConfig))
.withExpected(getExpectedAttributeValues())
.withRequestMetricCollector(
finalConfig.getRequestMetricCollector());
db.updateItem(applyUserAgent(req));
}
}
};
}
saveObjectHandler.execute();
}
/**
* The handler for saving object using DynamoDBMapper. Caller should
* implement the abstract methods to provide the expected behavior on each
* scenario, and this handler will take care of all the other basic workflow
* and common operations.
*/
protected abstract class SaveObjectHandler {
protected final Object object;
protected final Class clazz;
private String tableName;
private SaveBehavior saveBehavior;
private Map key;
private Map updateValues;
private Map expectedValues;
private List inMemoryUpdates;
private boolean nonKeyAttributePresent;
/**
* Constructs a handler for saving the specified model object.
*
* @param object The model object to be saved.
* @param clazz The domain class of the object.
* @param tableName The table name.
* @param userProvidedExpectedValues Any expected values that should be applied to the save
*/
public SaveObjectHandler(Class clazz, Object object, String tableName, SaveBehavior saveBehavior, Map userProvidedExpectedValues) {
this.clazz = clazz;
this.object = object;
this.tableName = tableName;
this.saveBehavior = saveBehavior;
updateValues = new HashMap();
expectedValues = new HashMap();
if(userProvidedExpectedValues != null){
expectedValues.putAll(userProvidedExpectedValues);
}
inMemoryUpdates = new LinkedList();
key = new HashMap();
nonKeyAttributePresent = false;
}
/**
* The general workflow of a save operation.
*/
public void execute() {
Collection keyGetters = reflector.getPrimaryKeyGetters(clazz);
/*
* First handle keys
*/
for ( Method method : keyGetters ) {
Object getterResult = safeInvoke(method, object);
String attributeName = reflector.getAttributeName(method);
if ( getterResult == null && reflector.isAssignableKey(method) ) {
onAutoGenerateAssignableKey(method, attributeName);
}
else {
AttributeValue newAttributeValue = getSimpleAttributeValue(method, getterResult);
if ( newAttributeValue == null ) {
throw new DynamoDBMappingException("Null or empty value for key: " + method);
}
onKeyAttributeValue(attributeName, newAttributeValue);
}
}
/*
* Next construct an update for every non-key property
*/
for ( Method method : reflector.getRelevantGetters(clazz) ) {
// Skip any key methods, since they are handled separately
if ( keyGetters.contains(method) )
continue;
Object getterResult = safeInvoke(method, object);
String attributeName = reflector.getAttributeName(method);
/*
* If this is a versioned field, update it
*/
if ( reflector.isVersionAttributeGetter(method) ) {
onVersionAttribute(method, getterResult, attributeName);
nonKeyAttributePresent = true;
}
/*
* Otherwise apply the update value for this attribute.
*/
else {
AttributeValue currentValue = getSimpleAttributeValue(method, getterResult);
if ( currentValue != null ) {
onNonKeyAttribute(attributeName, currentValue);
nonKeyAttributePresent = true;
} else {
onNullNonKeyAttribute(attributeName);
}
}
}
/*
* Execute the implementation of the low level request.
*/
executeLowLevelRequest(! nonKeyAttributePresent);
/*
* Finally, after the service call has succeeded, update the
* in-memory object with new field values as appropriate. This
* currently takes into account of auto-generated keys and versioned
* attributes.
*/
for ( ValueUpdate update : inMemoryUpdates ) {
update.apply();
}
}
/**
* Implement this method to do the necessary operations when a key
* attribute is set with some value.
*
* @param attributeName
* The name of the key attribute.
* @param keyAttributeValue
* The AttributeValue of the key attribute as specified in
* the object.
*/
protected abstract void onKeyAttributeValue(String attributeName, AttributeValue keyAttributeValue);
/**
* Implement this method for necessary operations when a non-key
* attribute is set a non-null value in the object.
* The default implementation simply adds a "PUT" update for the given attribute.
*
* @param attributeName
* The name of the non-key attribute.
* @param currentValue
* The updated value of the given attribute.
*/
protected void onNonKeyAttribute(String attributeName, AttributeValue currentValue) {
updateValues.put(attributeName, new AttributeValueUpdate()
.withValue(currentValue).withAction("PUT"));
}
/**
* Implement this method for necessary operations when a non-key
* attribute is set null in the object.
*
* @param attributeName
* The name of the non-key attribute.
*/
protected abstract void onNullNonKeyAttribute(String attributeName);
/**
* Implement this method to send the low-level request that is necessary
* to complete the save operation.
*
* @param onlyKeyAttributeSpecified
* Whether the object to be saved is only specified with key
* attributes.
*/
protected abstract void executeLowLevelRequest(boolean onlyKeyAttributeSpecified);
/** Get the SaveBehavior used locally for this save operation. **/
protected SaveBehavior getLocalSaveBehavior() {
return saveBehavior;
}
/** Get the table name **/
protected String getTableName() {
return tableName;
}
/** Get the map of all the specified key of the saved object. **/
protected Map getKeyAttributeValues() {
return key;
}
/** Get the map of AttributeValueUpdate on each modeled attribute. **/
protected Map getAttributeValueUpdates() {
return updateValues;
}
/** Get the map of ExpectedAttributeValue on each modeled attribute. **/
protected Map getExpectedAttributeValues() {
return expectedValues;
}
/** Get the list of all the necessary in-memory update on the object. **/
protected List getInMemoryUpdates() {
return inMemoryUpdates;
}
private void onAutoGenerateAssignableKey(Method method, String attributeName) {
AttributeValue newVersionValue = getAutoGeneratedKeyAttributeValue(method, null);
updateValues.put(attributeName,
new AttributeValueUpdate().withAction("PUT").withValue(newVersionValue));
inMemoryUpdates.add(new ValueUpdate(method, newVersionValue, object));
if ( getLocalSaveBehavior() != SaveBehavior.CLOBBER && !expectedValues.containsKey(attributeName)) {
// Add an expect clause to make sure that the item
// doesn't already exist, since it's supposed to be new
ExpectedAttributeValue expected = new ExpectedAttributeValue();
expected.setExists(false);
expectedValues.put(attributeName, expected);
}
}
private void onVersionAttribute(Method method, Object getterResult,
String attributeName) {
if ( getLocalSaveBehavior() != SaveBehavior.CLOBBER && !expectedValues.containsKey(attributeName)) {
// First establish the expected (current) value for the
// update call
ExpectedAttributeValue expected = new ExpectedAttributeValue();
// For new objects, insist that the value doesn't exist.
// For existing ones, insist it has the old value.
AttributeValue currentValue = getSimpleAttributeValue(method, getterResult);
expected.setExists(currentValue != null);
if ( currentValue != null ) {
expected.setValue(currentValue);
}
expectedValues.put(attributeName, expected);
}
AttributeValue newVersionValue = getVersionAttributeValue(method, getterResult);
updateValues
.put(attributeName, new AttributeValueUpdate().withAction("PUT").withValue(newVersionValue));
inMemoryUpdates.add(new ValueUpdate(method, newVersionValue, object));
}
}
/**
* Edge case to deal with the problem reported here:
* https://forums.aws.amazon.com/thread.jspa?threadID=86798&tstart=25
*
* DynamoDB fails silently on updateItem request that
*
* - is specified with a primary key that does not exist in the table
* - and contains only non-"PUT" AttributeValueUpdate on any non-key
* attribute.
*
*
* So we have to do a putItem when a key-only object is being saved with
* UPDATE configuration. In order to make sure this putItem request won't
* replace any existing item in the table, we also insist that an item with
* the key(s) given doesn't already exist. This isn't perfect, but we shouldn't
* be doing a putItem at all in this case, so it's the best we can do.
*
* @param config never null
*/
private void keyOnlyPut(
Class clazz,
Object object,
String tableName,
Method hashKeyGetter,
Method rangeKeyGetter,
Map userProvidedExpectedValues,
DynamoDBMapperConfig config) {
Map attributes = new HashMap();
Map expectedValues = new HashMap();
String hashKeyAttributeName = reflector.getAttributeName(hashKeyGetter);
Object hashGetterResult = safeInvoke(hashKeyGetter, object);
attributes.put(hashKeyAttributeName, getSimpleAttributeValue(hashKeyGetter, hashGetterResult));
expectedValues.put(hashKeyAttributeName, new ExpectedAttributeValue().withExists(false));
if (rangeKeyGetter != null) {
String rangeKeyAttributeName = reflector.getAttributeName(rangeKeyGetter);
Object rangeGetterResult = safeInvoke(rangeKeyGetter, object);
attributes.put(rangeKeyAttributeName, getSimpleAttributeValue(rangeKeyGetter, rangeGetterResult));
expectedValues.put(rangeKeyAttributeName, new ExpectedAttributeValue().withExists(false));
}
attributes = transformAttributes(
toParameters(attributes, clazz, config));
//overlay any user provided expected values.
if(userProvidedExpectedValues != null){
expectedValues.putAll(userProvidedExpectedValues);
}
PutItemRequest req = new PutItemRequest().withTableName(tableName)
.withItem(attributes).withExpected(expectedValues)
.withRequestMetricCollector(config.getRequestMetricCollector());
db.putItem(applyUserAgent(req));
}
/**
* Deletes the given object from its DynamoDB table using the default configuration.
*/
public void delete(Object object) {
delete(object, null, this.config);
}
/**
* Deletes the given object from its DynamoDB table using the specified deleteExpression and default configuration.
*/
public void delete(Object object, DynamoDBDeleteExpression deleteExpression) {
delete(object, deleteExpression, this.config);
}
/**
* Deletes the given object from its DynamoDB table using the specified configuration.
*/
public void delete(Object object, DynamoDBMapperConfig config) {
delete(object, null, config);
}
/**
* Deletes the given object from its DynamoDB table using the provided deleteExpression and provided configuration.
* Any options specified in the deleteExpression parameter will be overlaid on any constraints due to
* versioned attributes.
* @param deleteExpression
* The options to apply to this delete request
* @param config
* Config override object. If {@link SaveBehavior#CLOBBER} is
* supplied, version fields will not be considered when deleting
* the object.
*/
public void delete(T object, DynamoDBDeleteExpression deleteExpression, DynamoDBMapperConfig config) {
config = mergeConfig(config);
@SuppressWarnings("unchecked")
Class clazz = (Class) object.getClass();
String tableName = getTableName(clazz, config);
Map key = getKey(object, clazz);
/*
* If there is a version field, make sure we assert its value. If the
* version field is null (only should happen in unusual circumstances),
* pretend it doesn't have a version field after all.
*/
Map expectedValues = new HashMap();
if ( config.getSaveBehavior() != SaveBehavior.CLOBBER ) {
for ( Method method : reflector.getRelevantGetters(clazz) ) {
if ( reflector.isVersionAttributeGetter(method) ) {
Object getterResult = safeInvoke(method, object);
String attributeName = reflector.getAttributeName(method);
ExpectedAttributeValue expected = new ExpectedAttributeValue();
AttributeValue currentValue = getSimpleAttributeValue(method, getterResult);
expected.setExists(currentValue != null);
if ( currentValue != null )
expected.setValue(currentValue);
expectedValues.put(attributeName, expected);
break;
}
}
}
//Overlay any user provided expected values onto the generated ones
if(deleteExpression != null && deleteExpression.getExpected() != null){
expectedValues.putAll(deleteExpression.getExpected());
}
DeleteItemRequest req = applyUserAgent(new DeleteItemRequest()
.withKey(key).withTableName(tableName)
.withExpected(expectedValues))
.withRequestMetricCollector(config.getRequestMetricCollector())
;
db.deleteItem(req);
}
/**
* Deletes the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API. No
* version checks are performed, as required by the API.
*
* @see DynamoDBMapper#batchWrite(List, List, DynamoDBMapperConfig)
*/
public List batchDelete(List objectsToDelete) {
return batchWrite(Collections.emptyList(), objectsToDelete, this.config);
}
/**
* Deletes the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API. No
* version checks are performed, as required by the API.
*
* @see DynamoDBMapper#batchWrite(List, List, DynamoDBMapperConfig)
*/
public List batchDelete(Object... objectsToDelete) {
return batchWrite(Collections.emptyList(), Arrays.asList(objectsToDelete), this.config);
}
/**
* Saves the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API. No
* version checks are performed, as required by the API.
*
* This method ignores any SaveBehavior set on the mapper, and
* always behaves as if SaveBehavior.CLOBBER was specified, as
* the AmazonDynamoDB.batchWriteItem() request does not support updating
* existing items.
*
* @see DynamoDBMapper#batchWrite(List, List, DynamoDBMapperConfig)
*/
public List batchSave(List objectsToSave) {
return batchWrite(objectsToSave, Collections.emptyList(), this.config);
}
/**
* Saves the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API. No
* version checks are performed, as required by the API.
*
* This method ignores any SaveBehavior set on the mapper, and
* always behaves as if SaveBehavior.CLOBBER was specified, as
* the AmazonDynamoDB.batchWriteItem() request does not support updating
* existing items.
*
* @see DynamoDBMapper#batchWrite(List, List, DynamoDBMapperConfig)
*/
public List batchSave(Object... objectsToSave) {
return batchWrite(Arrays.asList(objectsToSave), Collections.emptyList(), this.config);
}
/**
* Saves and deletes the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API. No
* version checks are performed, as required by the API.
*
* This method ignores any SaveBehavior set on the mapper, and
* always behaves as if SaveBehavior.CLOBBER was specified, as
* the AmazonDynamoDB.batchWriteItem() request does not support updating
* existing items.
*
* @see DynamoDBMapper#batchWrite(List, List, DynamoDBMapperConfig)
*/
public List batchWrite(List objectsToWrite, List objectsToDelete) {
return batchWrite(objectsToWrite, objectsToDelete, this.config);
}
/**
* Saves and deletes the objects given using one or more calls to the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)} API.
*
* @param objectsToWrite
* A list of objects to save to DynamoDB. No version checks
* are performed, as required by the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)}
* API.
* @param objectsToDelete
* A list of objects to delete from DynamoDB. No version
* checks are performed, as required by the
* {@link AmazonDynamoDB#batchWriteItem(BatchWriteItemRequest)}
* API.
* @param config
* Only {@link DynamoDBMapperConfig#getTableNameOverride()} is
* considered; if specified, all objects in the two parameter
* lists will be considered to belong to the given table
* override. In particular, this method always acts as
* if SaveBehavior.CLOBBER was specified regardless of the
* value of the config parameter.
* @return A list of failed batches which includes the unprocessed items and
* the exceptions causing the failure.
*/
public List batchWrite(List objectsToWrite, List objectsToDelete, DynamoDBMapperConfig config) {
config = mergeConfig(config);
List totalFailedBatches = new LinkedList();
HashMap> requestItems = new HashMap>();
List inMemoryUpdates = new LinkedList();
for ( Object toWrite : objectsToWrite ) {
Class clazz = toWrite.getClass();
String tableName = getTableName(clazz, config);
Map attributeValues = new HashMap();
// Look at every getter and construct a value object for it
for ( Method method : reflector.getRelevantGetters(clazz) ) {
Object getterResult = safeInvoke(method, toWrite);
String attributeName = reflector.getAttributeName(method);
AttributeValue currentValue = null;
if ( getterResult == null && reflector.isAssignableKey(method) ) {
currentValue = getAutoGeneratedKeyAttributeValue(method, getterResult);
inMemoryUpdates.add(new ValueUpdate(method, currentValue, toWrite));
} else {
currentValue = getSimpleAttributeValue(method, getterResult);
}
if ( currentValue != null ) {
attributeValues.put(attributeName, currentValue);
}
}
if ( !requestItems.containsKey(tableName) ) {
requestItems.put(tableName, new LinkedList());
}
AttributeTransformer.Parameters parameters =
toParameters(attributeValues, clazz, config);
requestItems.get(tableName).add(
new WriteRequest().withPutRequest(
new PutRequest().withItem(
transformAttributes(parameters))));
}
for ( Object toDelete : objectsToDelete ) {
Class clazz = toDelete.getClass();
String tableName = getTableName(clazz, config);
Map key = getKey(toDelete);
if ( !requestItems.containsKey(tableName) ) {
requestItems.put(tableName, new LinkedList());
}
requestItems.get(tableName).add(
new WriteRequest().withDeleteRequest(new DeleteRequest().withKey(key)));
}
// Break into chunks of 25 items and make service requests to DynamoDB
while ( !requestItems.isEmpty() ) {
HashMap> batch = new HashMap>();
int i = 0;
Iterator>> tableIter = requestItems.entrySet().iterator();
while ( tableIter.hasNext() && i < 25 ) {
Entry> tableRequest = tableIter.next();
batch.put(tableRequest.getKey(), new LinkedList());
Iterator writeRequestIter = tableRequest.getValue().iterator();
while ( writeRequestIter.hasNext() && i++ < 25 ) {
WriteRequest writeRequest = writeRequestIter.next();
batch.get(tableRequest.getKey()).add(writeRequest);
writeRequestIter.remove();
}
// If we've processed all the write requests for this table,
// remove it from the parent iterator.
if ( !writeRequestIter.hasNext() ) {
tableIter.remove();
}
}
List failedBatches = writeOneBatch(batch);
if (failedBatches != null) {
totalFailedBatches.addAll(failedBatches);
// If contains throttling exception, we do a backoff
if (containsThrottlingException(failedBatches)) {
try {
Thread.sleep(1000 * 2);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new AmazonClientException(e.getMessage(), e);
}
}
}
}
// Once the entire batch is processed, update assigned keys in memory
for ( ValueUpdate update : inMemoryUpdates ) {
update.apply();
}
return totalFailedBatches;
}
/**
* Process one batch of requests(max 25). It will divide the batch if
* receives request too large exception(the total size of the request is beyond 1M).
*/
private List writeOneBatch(Map> batch) {
List failedBatches = new LinkedList();
Map> firstHalfBatch = new HashMap>();
Map> secondHalfBatch = new HashMap>();
FailedBatch failedBatch = callUntilCompletion(batch);
if (failedBatch != null) {
// If the exception is request entity too large, we divide the batch
// into smaller parts.
if (failedBatch.getException() instanceof AmazonServiceException
&& RetryUtils.isRequestEntityTooLargeException((AmazonServiceException) failedBatch.getException())) {
// If only one item left, the item size must beyond 64k, which
// exceedes the limit.
if (computeFailedBatchSize(failedBatch) == 1) {
failedBatches.add(failedBatch);
} else {
divideBatch(batch, firstHalfBatch, secondHalfBatch);
failedBatches.addAll(writeOneBatch(firstHalfBatch));
failedBatches.addAll(writeOneBatch(secondHalfBatch));
}
} else {
failedBatches.add(failedBatch);
}
}
return failedBatches;
}
/**
* Check whether there are throttling exception in the failed batches.
*/
private boolean containsThrottlingException (List failedBatches) {
for (FailedBatch failedBatch : failedBatches) {
Exception e = failedBatch.getException();
if (e instanceof AmazonServiceException
&& RetryUtils.isThrottlingException((AmazonServiceException) e)) {
return true;
}
}
return false;
}
/**
* Divide the batch of objects to save into two smaller batches. Each contains half of the elements.
*/
private void divideBatch(Map> batch, Map> firstHalfBatch, Map> secondHalfBatch) {
for (String key : batch.keySet()) {
List requests = batch.get(key);
List firstHalfRequests = requests.subList(0, requests.size() / 2);
List secondHalfRequests = requests.subList(requests.size() / 2, requests.size());
firstHalfBatch.put(key, firstHalfRequests);
secondHalfBatch.put(key, secondHalfRequests);
}
}
/**
* Count the total number of unprocessed items in the failed batch.
*/
private int computeFailedBatchSize(FailedBatch failedBatch) {
int count = 0;
for (String tableName : failedBatch.getUnprocessedItems().keySet()) {
count += failedBatch.getUnprocessedItems().get(tableName).size();
}
return count;
}
/**
* Continue trying to process the batch until it finishes or an exception
* occurs.
*/
private FailedBatch callUntilCompletion(Map> batch) {
BatchWriteItemResult result = null;
int retries = 0;
FailedBatch failedBatch = null;
while (true) {
try {
result = db.batchWriteItem(new BatchWriteItemRequest().withRequestItems(batch));
} catch (Exception e) {
failedBatch = new FailedBatch();
failedBatch.setUnprocessedItems(batch);
failedBatch.setException(e);
return failedBatch;
}
retries++;
batch = result.getUnprocessedItems();
if (batch.size() > 0) {
pauseExponentially(retries);
} else {
break;
}
}
return failedBatch;
}
/**
* Retrieves multiple items from multiple tables using their primary keys.
*
* @see DynamoDBMapper#batchLoad(List, DynamoDBMapperConfig)
*/
public Map> batchLoad(List