Voice Notifications Using Java

    Overview

    This guide shows how to send audio notifications using voice calls. You can play recorded audio when the call recipient answers or use text-to-speech, as we show here, combining static text with dynamic information that Plivo gets from a variable.

    You can use voice notification for use cases such as:

    • Order notification
    • Booking status
    • Delivery status
    • Flight cancellation/rescheduling
    • Two-factor authentication/one-time password
    • New offer notification
    • Account balance notification

    Implement voice notification either by using our PHLO visual workflow builder or our APIs and XML documents. Follow the instructions in one of the tabs below.

    You can create and deploy a PHLO to send voice notifications with a few clicks on the PHLO canvas.

    How it works

    Prerequisites

    To get started, you need a Plivo account — sign up with your work email address if you don’t have one already. If this is your first time triggering a PHLO with Java, follow our instructions to set up a Java development environment.

    Create the PHLO

    To create a PHLO, visit the PHLO page of the Plivo console. If this is your first PHLO, the PHLO page will be empty.

    • Click Create New PHLO.
    • In the Choose your use case pop-up, click Build my own. The PHLO canvas will appear with the Start node.

      Note: The Start node is the starting point of any PHLO. It lets you trigger a PHLO to start upon one of three actions: incoming SMS message, incoming call, or API request.
    • Click the Start node to open the Configurations tab, then enter the information to retrieve from the HTTP Request payload — in this case, the From and To numbers for the call, and an item number.

    • From the list of components on the left side, drag and drop the Initiate Call component onto the canvas. This adds an Initiate Call node onto the canvas. When a component is placed on the canvas it becomes a node.

    • Draw a line to connect the Start node’s API Request trigger state to the Initiate Call node.

    • In the Configuration tab of the Initiate Call node, give the node a name. To enter values for the From and To fields, enter two curly brackets to view all available variables, and choose the appropriate ones. The values for the numbers will be retrieved from the HTTP Request payload you defined in the Start node.

    • Validate the configuration by clicking Validate. Do the same for each node as you go along.

    • Next, create a node from the Play Audio component. Connect the Initiate Call node to the Play Audio node using the Answered trigger state.

    • Configure the Play Audio node to play a message to the user by entering text in the Speak Text box in the Prompt section of the Configuration pane.

      • Audio playback can either be static or dynamic. You define a static payload by specifying values when you create the PHLO, and a dynamic payload by passing values through Liquid templating parameters when you trigger the PHLO from your application.
      • On the Play Audio Configuration tab, enter a static message (for example, “Your order has been successfully placed”) in the Speak Text field, with a variable to include the dynamic text. Enter two curly brackets to view all available variables. Choose the item number you defined in the Start node configuration tab.
    • After you complete and validate the node configurations, give the PHLO a name by clicking in the upper left, then click Save.

    Your completed PHLO should look like this:

    Voice Notification

    Your PHLO is now ready to test.

    Trigger the PHLO

    You integrate a PHLO into your application workflow by making an API request to trigger the PHLO with the required payload — the set of parameters you pass to the PHLO. You can define a static payload by specifying values when you create the PHLO, or define a dynamic payload by passing values through parameters when you trigger the PHLO from your application.

    With a static payload

    When you configure values when creating the PHLO, they act as a static payload.

    With Static Payload

    Code

    Create a Java class in the project called TriggerPhlo and paste into it this code.

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    import com.plivo.api.Plivo;
    import com.plivo.api.PlivoClient;
    import com.plivo.api.exceptions.PlivoRestException;
    import com.plivo.api.models.phlo.Phlo;
    import java.io.IOException;
    
    public class Example
    {
        private static final String authId = "<auth_id>";
        private static final String authToken = "<auth_token>";
        private static PlivoClient client = new PlivoClient(authId, authToken);
        public static void main(String[] args) throws IOException, PlivoRestException
        {
            String phloId = "<phlo_id>";
            Plivo.init(authId, authToken);
            Phlo phlo = Phlo.getter(phloId).client(client).get();
            PhloUpdateResponse response = Phlo.updater(phloId).payload().run();
        }
    }
    

    Replace the auth placeholders with your authentication credentials from the Plivo console. Replace the phlo_id placeholder with your PHLO ID from the Plivo console.

    With a dynamic payload

    To use dynamic values for the parameters, use Liquid templating parameters when you create the PHLO and pass the values from your code to the PHLO when you trigger it.

    With Dynamic Payload

    Code

    Create a Java class in the project called TriggerPhlo and paste into it this code.

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    import com.plivo.api.Plivo;
    import com.plivo.api.PlivoClient;
    import com.plivo.api.exceptions.PlivoRestException;
    import com.plivo.api.models.phlo.Phlo;
    import java.io.IOException;
    
    public class Example
    {
        private static final String authId = "<auth_id>";
        private static final String authToken = "<auth_token>";
        private static PlivoClient client = new PlivoClient(authId, authToken);
        public static void main(String[] args) throws IOException, PlivoRestException
        {
            String phloId = "<phlo_id>";
            Plivo.init(authId, authToken);
            Phlo phlo = Phlo.getter(phloId).client(client).get();
            Map<String, Object> payload = new HashMap<>();
            payload.put("from", "<caller_id>");
            payload.put("to", "<destination_number>");
            PhloUpdateResponse response = Phlo.updater(phloId).payload(payload).run();
        }
    }
    

    Replace the auth placeholders with your authentication credentials from the Plivo console. Replace the phlo_id placeholder with your PHLO ID from the Plivo console. Replace the phone number placeholders with actual phone numbers in E.164 format (for example, +12025551234).

    Test

    Save the file and run it.

    Note: If you’re using a Plivo Trial account, you can make calls only to phone numbers that have been verified with Plivo. You can verify (sandbox) a number by going to the console’s Phone Numbers > Sandbox Numbers page.

    Here’s how to use Plivo APIs and XML to implement voice notifications.

    How it works

    Outbound Call Flow

    Plivo requests an answer URL when the call is answered (step 4) and expects the file at that address to hold a valid XML response from the application with instructions on how to handle the call. To see how this works, you can use https://s3.amazonaws.com/static.plivo.com/notification.xml as an answer URL to test your first outgoing call. The file contains this XML code:

    <Response> 
    <Speak>Congratulations, your order was successfully placed</Speak> 
    </Response>
    

    This code instructs Plivo to say, “Congratulations, your order was successfully placed” to the call recipient. You can find the entire list of valid Plivo XML verbs in our XML Reference documentation.

    Prerequisites

    To get started, you need a Plivo account — sign up with your work email address if you don’t have one already. If this is your first time using Plivo APIs, follow our instructions to set up a Java development environment.

    Create a voice notification application in Java

    Create a Java class in the project MakeCall and paste into it this code.

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    import java.io.IOException;
    import java.util.Collections;
    import com.plivo.api.Plivo;
    import com.plivo.api.exceptions.PlivoRestException;
    import com.plivo.api.models.call.Call;
    import com.plivo.api.models.call.CallCreateResponse;
    
    class MakeCall {
        public static void main(String [] args) throws IOException, PlivoRestException {
            Plivo.init("<auth_id>","<auth_token>");
            CallCreateResponse response = Call.creator("<caller_id>",
                    Collections.singletonList("<destination_number>"),
                    "https://s3.amazonaws.com/static.plivo.com/notification.xml")
                    .answerMethod("GET")
                    .create();
            System.out.println(response);
        }
    }
    

    Replace the auth placeholders with your authentication credentials from the Plivo console. Replace the phone number placeholders with actual phone numbers in E.164 format (for example, +12025551234).

    Note: We recommend that you store your credentials in the auth_id and auth_token environment variables, to avoid the possibility of accidentally committing them to source control. If you do this, you can initialize the client with no arguments and Plivo will automatically fetch the values from the environment variables. You can use System.getenv() to store environment variables and retrieve them when initializing the client.

    Test

    Save the file and run it.

    Make Call

    Note: If you’re using a Plivo Trial account, you can make calls only to phone numbers that have been verified with Plivo. You can verify (sandbox) a number by going to the console’s Phone Numbers > Sandbox Numbers page.