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Object Oriented Wrapper of Amazon DynamoDB SDK
/**
* Copyright (c) 2012-2017, jcabi.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met: 1) Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer. 2) Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution. 3) Neither the name of the jcabi.com nor
* the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.jcabi.dynamo;
import com.amazonaws.AmazonClientException;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.Condition;
import com.amazonaws.services.dynamodbv2.model.QueryRequest;
import com.amazonaws.services.dynamodbv2.model.QueryResult;
import com.amazonaws.services.dynamodbv2.model.ReturnConsumedCapacity;
import com.amazonaws.services.dynamodbv2.model.Select;
import com.google.common.collect.Iterables;
import com.jcabi.aspects.Immutable;
import com.jcabi.aspects.Loggable;
import com.jcabi.aspects.Tv;
import com.jcabi.log.Logger;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import lombok.EqualsAndHashCode;
import lombok.ToString;
/**
* Query-based valve.
*
* @author Yegor Bugayenko ([email protected])
* @version $Id: e21837da3ee34618f275d65ee715922d573260aa $
* @since 0.1
*/
@Immutable
@ToString
@Loggable(Loggable.DEBUG)
@EqualsAndHashCode(of = { "limit", "forward" })
@SuppressWarnings("PMD.TooManyMethods")
public final class QueryValve implements Valve {
/**
* Limit to use for every query.
*/
private final transient int limit;
/**
* Forward/reverse order.
*/
private final transient boolean forward;
/**
* Attributes to fetch.
*/
@Immutable.Array
private final transient String[] attributes;
/**
* Index name.
*/
private final transient String index;
/**
* What attributes to select.
*/
private final transient String select;
/**
* Consistent read.
*/
private final transient boolean consistent;
/**
* Public ctor.
*/
public QueryValve() {
this(
Tv.TWENTY, true, new ArrayList(0),
"", Select.SPECIFIC_ATTRIBUTES.toString(), true
);
}
/**
* Public ctor.
* @param lmt Limit
* @param fwd Forward
* @param attrs Names of attributes to pre-fetch
* @param idx Index name or empty string
* @param slct Select
* @param cnst Consistent read
* @checkstyle ParameterNumber (5 lines)
*/
private QueryValve(final int lmt, final boolean fwd,
final Iterable attrs, final String idx,
final String slct, final boolean cnst) {
this.limit = lmt;
this.forward = fwd;
this.attributes = Iterables.toArray(attrs, String.class);
this.index = idx;
this.select = slct;
this.consistent = cnst;
}
// @checkstyle ParameterNumber (5 lines)
@Override
public Dosage fetch(final Credentials credentials, final String table,
final Map conditions, final Collection keys)
throws IOException {
final AmazonDynamoDB aws = credentials.aws();
try {
final Collection attrs = new HashSet(
Arrays.asList(this.attributes)
);
attrs.addAll(keys);
QueryRequest request = new QueryRequest()
.withTableName(table)
.withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL)
.withKeyConditions(conditions)
.withConsistentRead(this.consistent)
.withScanIndexForward(this.forward)
.withSelect(this.select)
.withLimit(this.limit);
if (this.select.equals(Select.SPECIFIC_ATTRIBUTES.toString())) {
request = request.withAttributesToGet(attrs);
}
if (!this.index.isEmpty()) {
request = request.withIndexName(this.index);
}
final long start = System.currentTimeMillis();
final QueryResult result = aws.query(request);
Logger.info(
this,
// @checkstyle LineLength (1 line)
"#items(): loaded %d item(s) from '%s' and stopped at %s, using %s, %s, in %[ms]s",
result.getCount(), table,
result.getLastEvaluatedKey(),
conditions,
new PrintableConsumedCapacity(
result.getConsumedCapacity()
).print(),
System.currentTimeMillis() - start
);
return new QueryValve.NextDosage(credentials, request, result);
} catch (final AmazonClientException ex) {
throw new IOException(
String.format(
"Failed to fetch from \"%s\" by %s and %s",
table, conditions, keys
),
ex
);
} finally {
aws.shutdown();
}
}
@Override
public int count(final Credentials credentials, final String table,
final Map conditions) throws IOException {
final AmazonDynamoDB aws = credentials.aws();
try {
QueryRequest request = new QueryRequest()
.withTableName(table)
.withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL)
.withKeyConditions(conditions)
.withConsistentRead(this.consistent)
.withSelect(Select.COUNT)
.withLimit(Integer.MAX_VALUE);
if (!this.index.isEmpty()) {
request = request.withIndexName(this.index);
}
final long start = System.currentTimeMillis();
final QueryResult rslt = aws.query(request);
final int count = rslt.getCount();
Logger.info(
this,
// @checkstyle LineLength (1 line)
"#total(): COUNT=%d in '%s' using %s, %s, in %[ms]s",
count, request.getTableName(), request.getQueryFilter(),
new PrintableConsumedCapacity(
rslt.getConsumedCapacity()
).print(),
System.currentTimeMillis() - start
);
return count;
} catch (final AmazonClientException ex) {
throw new IOException(
String.format(
"Failed to count from \"%s\" by %s",
table, conditions
),
ex
);
} finally {
aws.shutdown();
}
}
/**
* With consistent read.
* @param cnst Consistent read
* @return New query valve
* @see QueryRequest#withConsistentRead(Boolean)
* @since 0.12
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withConsistentRead(final boolean cnst) {
return new QueryValve(
this.limit, this.forward,
Arrays.asList(this.attributes),
this.index, this.select, cnst
);
}
/**
* With index name.
* @param idx Index name
* @return New query valve
* @see QueryRequest#withIndexName(String)
* @since 0.10.2
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withIndexName(final String idx) {
return new QueryValve(
this.limit, this.forward,
Arrays.asList(this.attributes),
idx, this.select, this.consistent
);
}
/**
* With attributes to select.
* @param slct Select to use
* @return New query valve
* @see QueryRequest#withSelect(Select)
* @since 0.10.2
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withSelect(final Select slct) {
return new QueryValve(
this.limit, this.forward,
Arrays.asList(this.attributes), this.index,
slct.toString(), this.consistent
);
}
/**
* With given limit.
* @param lmt Limit to use
* @return New query valve
* @see QueryRequest#withLimit(Integer)
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withLimit(final int lmt) {
return new QueryValve(
lmt, this.forward,
Arrays.asList(this.attributes),
this.index, this.select, this.consistent
);
}
/**
* With scan index forward flag.
* @param fwd Forward flag
* @return New query valve
* @see QueryRequest#withScanIndexForward(Boolean)
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withScanIndexForward(final boolean fwd) {
return new QueryValve(
this.limit, fwd,
Arrays.asList(this.attributes),
this.index, this.select, this.consistent
);
}
/**
* With this extra attribute to pre-fetch.
* @param name Name of attribute to pre-load
* @return New query valve
* @see QueryRequest#withAttributesToGet(Collection)
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withAttributeToGet(final String name) {
return new QueryValve(
this.limit, this.forward,
Iterables.concat(
Arrays.asList(this.attributes),
Collections.singleton(name)
),
this.index, this.select, this.consistent
);
}
/**
* With these extra attributes to pre-fetch.
* @param names Name of attributes to pre-load
* @return New query valve
* @see QueryRequest#withAttributesToGet(Collection)
* @checkstyle AvoidDuplicateLiterals (5 line)
*/
public QueryValve withAttributesToGet(final String... names) {
return new QueryValve(
this.limit, this.forward,
Iterables.concat(
Arrays.asList(this.attributes),
Arrays.asList(names)
),
this.index,
this.select, this.consistent
);
}
/**
* Next dosage.
*/
@ToString
@Loggable(Loggable.DEBUG)
@EqualsAndHashCode(of = { "credentials", "request", "result" })
private final class NextDosage implements Dosage {
/**
* AWS client.
*/
private final transient Credentials credentials;
/**
* Query request.
*/
private final transient QueryRequest request;
/**
* Query request.
*/
private final transient QueryResult result;
/**
* Public ctor.
* @param creds Credentials
* @param rqst Query request
* @param rslt Query result
*/
NextDosage(final Credentials creds, final QueryRequest rqst,
final QueryResult rslt) {
this.credentials = creds;
this.request = rqst;
this.result = rslt;
}
@Override
public List> items() {
return this.result.getItems();
}
@Override
public boolean hasNext() {
return this.result.getLastEvaluatedKey() != null;
}
@Override
public Dosage next() {
if (!this.hasNext()) {
throw new IllegalStateException(
"Nothing left in the iterator"
);
}
final AmazonDynamoDB aws = this.credentials.aws();
try {
final QueryRequest rqst =
this.request.withExclusiveStartKey(
this.result.getLastEvaluatedKey()
);
final long start = System.currentTimeMillis();
final QueryResult rslt = aws.query(rqst);
Logger.info(
this,
// @checkstyle LineLength (1 line)
"#next(): loaded %d item(s) from '%s' and stopped at %s, using %s, %s, in %[ms]s",
rslt.getCount(), rqst.getTableName(),
rslt.getLastEvaluatedKey(),
rqst.getKeyConditions(),
new PrintableConsumedCapacity(
rslt.getConsumedCapacity()
).print(),
System.currentTimeMillis() - start
);
return new QueryValve.NextDosage(this.credentials, rqst, rslt);
} finally {
aws.shutdown();
}
}
}
}