Example usage for com.amazonaws.services.dynamodbv2.model AttributeAction ADD

Introduction

In this page you can find the example usage for com.amazonaws.services.dynamodbv2.model AttributeAction ADD.

Prototype

AttributeAction ADD

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Usage

From source file:com.lvl6.mobsters.dynamo.setup.TransactionExamples.java

License:Open Source License

/**
 * This example shows an example of how to handle errors
 *///w  w w .  j a va  2s  . co m
public void badRequest() throws RuntimeException {
    print("\n*** badRequest() ***\n");

    // Create a "success" flag and set it to false.  We'll roll back the transaction in a finally {} if this wasn't set to true by then.
    boolean success = false;
    Transaction t1 = txManager.newTransaction();

    try {
        // Construct a request that we know DynamoDB will reject.
        Map<String, AttributeValue> key = new HashMap<String, AttributeValue>();
        key.put(EXAMPLE_TABLE_HASH_KEY, new AttributeValue("Item1"));

        // You cannot "add" a String type attribute.  This request will be rejected by DynamoDB.
        Map<String, AttributeValueUpdate> updates = new HashMap<String, AttributeValueUpdate>();
        updates.put("Will this work?", new AttributeValueUpdate().withAction(AttributeAction.ADD)
                .withValue(new AttributeValue("Nope.")));

        // The transaction library will make the request here, so we actually see
        print("Making invalid request");
        t1.updateItem(new UpdateItemRequest().withTableName(EXAMPLE_TABLE_NAME).withKey(key)
                .withAttributeUpdates(updates));

        t1.commit();
        success = true;
        throw new RuntimeException("This should NOT have happened (actually should have failed before commit)");
    } catch (AmazonServiceException e) {
        print("Caught a ValidationException. This is what we expected. The transaction will be rolled back: "
                + e.getMessage());
        // in a real application, you'll probably want to throw an exception to your caller 
    } finally {
        if (!success) {
            print("The transaction didn't work, as expected.  Rolling back.");
            // It can be a good idea to use a "success" flag in this way, to ensure that you roll back if you get any exceptions 
            // from the transaction library, or from DynamoDB, or any from the DynamoDB client library.  These 3 exception base classes are:
            // TransactionException, AmazonServiceException, or AmazonClientExeption.
            // If you forget to roll back, no problem - another transaction will come along and roll yours back eventually.
            try {
                t1.rollback();
            } catch (TransactionException te) {
            } // ignore, but should probably log
        }

        try {
            t1.delete();
        } catch (TransactionException te) {
        } // ignore, but should probably log
    }
}

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From source file:com.nandanu.halomama.controller.DynamoDBRouter.java

License:Open Source License

public void incrementSeen(String userNameTwitter, String createdDate) {
    UpdateItemRequest upd = new UpdateItemRequest();

    upd.setTableName(Constants.TABLE_NAME);

    AttributeValue unt = new AttributeValue();
    unt.setS(userNameTwitter);/*  ww w .jav  a 2 s.c om*/
    AttributeValue cd = new AttributeValue();
    cd.setS(createdDate);

    upd.addKeyEntry(Constants.TAG_USERNAME, unt);
    upd.addKeyEntry(Constants.TAG_CREATED_DATE, cd);

    AttributeValue s = new AttributeValue();
    s.setN("1");

    AttributeValueUpdate seen = new AttributeValueUpdate(s, AttributeAction.ADD);

    upd.addAttributeUpdatesEntry(Constants.TAG_SEEN, seen);

    dDBClient.updateItem(upd);

}

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