Step 1: Create a new ledger

In this step, you create a new Amazon QLDB ledger named vehicle-registration.

To create a new ledger

Review the following file (Constants.java), which contains constant values that are used by all of the other programs in this tutorial.

2.x


/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazon.ion.IonSystem;
import com.amazon.ion.system.IonSystemBuilder;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.dataformat.ion.IonObjectMapper;
import com.fasterxml.jackson.dataformat.ion.ionvalue.IonValueMapper;

/**
 * Constant values used throughout this tutorial.
 */
public final class Constants {
    public static final int RETRY_LIMIT = 4;
    public static final String LEDGER_NAME = "vehicle-registration";
    public static final String STREAM_NAME = "vehicle-registration-stream";
    public static final String VEHICLE_REGISTRATION_TABLE_NAME = "VehicleRegistration";
    public static final String VEHICLE_TABLE_NAME = "Vehicle";
    public static final String PERSON_TABLE_NAME = "Person";
    public static final String DRIVERS_LICENSE_TABLE_NAME = "DriversLicense";
    public static final String VIN_INDEX_NAME = "VIN";
    public static final String PERSON_GOV_ID_INDEX_NAME = "GovId";
    public static final String VEHICLE_REGISTRATION_LICENSE_PLATE_NUMBER_INDEX_NAME = "LicensePlateNumber";
    public static final String DRIVER_LICENSE_NUMBER_INDEX_NAME = "LicenseNumber";
    public static final String DRIVER_LICENSE_PERSONID_INDEX_NAME = "PersonId";
    public static final String JOURNAL_EXPORT_S3_BUCKET_NAME_PREFIX = "qldb-tutorial-journal-export";
    public static final String USER_TABLES = "information_schema.user_tables";
    public static final String LEDGER_NAME_WITH_TAGS = "tags";
    public static final IonSystem SYSTEM = IonSystemBuilder.standard().build();
    public static final IonObjectMapper MAPPER = new IonValueMapper(SYSTEM);

    private Constants() { }

    static {
        MAPPER.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    }
}

1.x

Important

For the Amazon Ion package, you must use the namespace com.amazon.ion in your application. The AWS SDK for Java depends on another Ion package under the namespace software.amazon.ion, but this is a legacy package that is not compatible with the QLDB driver.


/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazon.ion.IonSystem;
import com.amazon.ion.system.IonSystemBuilder;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.dataformat.ion.IonObjectMapper;
import com.fasterxml.jackson.dataformat.ion.ionvalue.IonValueMapper;

/**
 * Constant values used throughout this tutorial.
 */
public final class Constants {
    public static final int RETRY_LIMIT = 4;
    public static final String LEDGER_NAME = "vehicle-registration";
    public static final String STREAM_NAME = "vehicle-registration-stream";
    public static final String VEHICLE_REGISTRATION_TABLE_NAME = "VehicleRegistration";
    public static final String VEHICLE_TABLE_NAME = "Vehicle";
    public static final String PERSON_TABLE_NAME = "Person";
    public static final String DRIVERS_LICENSE_TABLE_NAME = "DriversLicense";
    public static final String VIN_INDEX_NAME = "VIN";
    public static final String PERSON_GOV_ID_INDEX_NAME = "GovId";
    public static final String VEHICLE_REGISTRATION_LICENSE_PLATE_NUMBER_INDEX_NAME = "LicensePlateNumber";
    public static final String DRIVER_LICENSE_NUMBER_INDEX_NAME = "LicenseNumber";
    public static final String DRIVER_LICENSE_PERSONID_INDEX_NAME = "PersonId";
    public static final String JOURNAL_EXPORT_S3_BUCKET_NAME_PREFIX = "qldb-tutorial-journal-export";
    public static final String USER_TABLES = "information_schema.user_tables";
    public static final String LEDGER_NAME_WITH_TAGS = "tags";
    public static final IonSystem SYSTEM = IonSystemBuilder.standard().build();
    public static final IonObjectMapper MAPPER = new IonValueMapper(SYSTEM);

    private Constants() { }

    static {
        MAPPER.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    }
}

Note

This Constants class includes an instance of the open-source Jackson IonValueMapper class. You can use this mapper to process your Amazon Ion data when doing read and write transactions.

The CreateLedger.java file also has a dependency on the following program (DescribeLedger.java), which describes the current status of your ledger.


/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazonaws.services.qldb.AmazonQLDB;
import com.amazonaws.services.qldb.model.DescribeLedgerRequest;
import com.amazonaws.services.qldb.model.DescribeLedgerResult;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Describe a QLDB ledger.
 *
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class DescribeLedger {
    public static AmazonQLDB client = CreateLedger.getClient();
    public static final Logger log = LoggerFactory.getLogger(DescribeLedger.class);

    private DescribeLedger() { }

    public static void main(final String... args) {
        try {

            describe(Constants.LEDGER_NAME);

        } catch (Exception e) {
            log.error("Unable to describe a ledger!", e);
        }
    }

    /**
     * Describe a ledger.
     *
     * @param name
     *              Name of the ledger to describe.
     * @return {@link DescribeLedgerResult} from QLDB.
     */
    public static DescribeLedgerResult describe(final String name) {
        log.info("Let's describe ledger with name: {}...", name);
        DescribeLedgerRequest request = new DescribeLedgerRequest().withName(name);
        DescribeLedgerResult result = client.describeLedger(request);
        log.info("Success. Ledger description: {}", result);
        return result;
    }
}

Compile and run the CreateLedger.java program to create a ledger named vehicle-registration.

2.x


/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.qldb.AmazonQLDB;
import com.amazonaws.services.qldb.AmazonQLDBClientBuilder;
import com.amazonaws.services.qldb.model.CreateLedgerRequest;
import com.amazonaws.services.qldb.model.CreateLedgerResult;
import com.amazonaws.services.qldb.model.DescribeLedgerResult;
import com.amazonaws.services.qldb.model.LedgerState;
import com.amazonaws.services.qldb.model.PermissionsMode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Create a ledger and wait for it to be active.
 * <p>
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class CreateLedger {
    public static final Logger log = LoggerFactory.getLogger(CreateLedger.class);
    public static final Long LEDGER_CREATION_POLL_PERIOD_MS = 10_000L;
    public static String endpoint = null;
    public static String region = null;
    public static AmazonQLDB client = getClient();

    private CreateLedger() {
    }

    /**
     * Build a low-level QLDB client.
     *
     * @return {@link AmazonQLDB} control plane client.
     */
    public static AmazonQLDB getClient() {
        AmazonQLDBClientBuilder builder = AmazonQLDBClientBuilder.standard();
        if (null != endpoint && null != region) {
            builder.setEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint, region));
        }
        return builder.build();
    }

    public static void main(final String... args) throws Exception {
        try {
            client = getClient();

            create(Constants.LEDGER_NAME);

            waitForActive(Constants.LEDGER_NAME);

        } catch (Exception e) {
            log.error("Unable to create the ledger!", e);
            throw e;
        }
    }

    /**
     * Create a new ledger with the specified ledger name.
     *
     * @param ledgerName Name of the ledger to be created.
     * @return {@link CreateLedgerResult} from QLDB.
     */
    public static CreateLedgerResult create(final String ledgerName) {
        log.info("Let's create the ledger with name: {}...", ledgerName);
        CreateLedgerRequest request = new CreateLedgerRequest()
                .withName(ledgerName)
                .withPermissionsMode(PermissionsMode.ALLOW_ALL);
        CreateLedgerResult result = client.createLedger(request);
        log.info("Success. Ledger state: {}.", result.getState());
        return result;
    }

    /**
     * Wait for a newly created ledger to become active.
     *
     * @param ledgerName Name of the ledger to wait on.
     * @return {@link DescribeLedgerResult} from QLDB.
     * @throws InterruptedException if thread is being interrupted.
     */
    public static DescribeLedgerResult waitForActive(final String ledgerName) throws InterruptedException {
        log.info("Waiting for ledger to become active...");
        while (true) {
            DescribeLedgerResult result = DescribeLedger.describe(ledgerName);
            if (result.getState().equals(LedgerState.ACTIVE.name())) {
                log.info("Success. Ledger is active and ready to use.");
                return result;
            }
            log.info("The ledger is still creating. Please wait...");
            Thread.sleep(LEDGER_CREATION_POLL_PERIOD_MS);
        }
    }
}

1.x


/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazonaws.services.qldb.AmazonQLDB;
import com.amazonaws.services.qldb.AmazonQLDBClientBuilder;
import com.amazonaws.services.qldb.model.CreateLedgerRequest;
import com.amazonaws.services.qldb.model.CreateLedgerResult;
import com.amazonaws.services.qldb.model.DescribeLedgerResult;
import com.amazonaws.services.qldb.model.LedgerState;
import com.amazonaws.services.qldb.model.PermissionsMode;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Create a ledger and wait for it to be active.
 *
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class CreateLedger {
    public static final Logger log = LoggerFactory.getLogger(CreateLedger.class);
    public static final Long LEDGER_CREATION_POLL_PERIOD_MS = 10_000L;
    public static AmazonQLDB client = getClient();

    private CreateLedger() { }

    /**
     * Build a low-level QLDB client.
     *
     * @return {@link AmazonQLDB} control plane client.
     */
    public static AmazonQLDB getClient() {
        return AmazonQLDBClientBuilder.standard().build();
    }

    public static void main(final String... args) throws Exception {
        try {

            create(Constants.LEDGER_NAME);

            waitForActive(Constants.LEDGER_NAME);

        } catch (Exception e) {
            log.error("Unable to create the ledger!", e);
            throw e;
        }
    }

    /**
     * Create a new ledger with the specified ledger name.
     *
     * @param ledgerName
     *              Name of the ledger to be created.
     * @return {@link CreateLedgerResult} from QLDB.
     */
    public static CreateLedgerResult create(final String ledgerName) {
        log.info("Let's create the ledger with name: {}...", ledgerName);
        CreateLedgerRequest request = new CreateLedgerRequest()
                .withName(ledgerName)
                .withPermissionsMode(PermissionsMode.ALLOW_ALL);
        CreateLedgerResult result = client.createLedger(request);
        log.info("Success. Ledger state: {}.", result.getState());
        return result;
    }

    /**
     * Wait for a newly created ledger to become active.
     *
     * @param ledgerName
     *              Name of the ledger to wait on.
     * @return {@link DescribeLedgerResult} from QLDB.
     * @throws InterruptedException if thread is being interrupted.
     */
    public static DescribeLedgerResult waitForActive(final String ledgerName) throws InterruptedException {
        log.info("Waiting for ledger to become active...");
        while (true) {
            DescribeLedgerResult result = DescribeLedger.describe(ledgerName);
            if (result.getState().equals(LedgerState.ACTIVE.name())) {
                log.info("Success. Ledger is active and ready to use.");
                return result;
            }
            log.info("The ledger is still creating. Please wait...");
            Thread.sleep(LEDGER_CREATION_POLL_PERIOD_MS);
        }
    }
}

Note

In the createLedger call, you must specify a ledger name and a permissions mode. We recommend using the STANDARD permissions mode to maximize the security of your ledger data.
When you create a ledger, deletion protection is enabled by default. This is a feature in QLDB that prevents ledgers from being deleted by any user. You have the option of disabling deletion protection on ledger creation using the QLDB API or the AWS Command Line Interface (AWS CLI).
Optionally, you can also specify tags to attach to your ledger.

To verify your connection to the new ledger, proceed to Step 2: Test connectivity to the ledger.

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Document Conventions

Installing the sample application

Step 2: Test connectivity