app-store-optimization/skills/official/microsoft/java/communication/common/SKILL.md

name, description, package

name	description	package
azure-communication-common-java	Azure Communication Services common utilities for Java. Use when working with CommunicationTokenCredential, user identifiers, token refresh, or shared authentication across ACS services.	com.azure:azure-communication-common

Azure Communication Common (Java)

Shared authentication utilities and data structures for Azure Communication Services.

Installation

<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-communication-common</artifactId>
    <version>1.4.0</version>
</dependency>

Key Concepts

Class	Purpose
CommunicationTokenCredential	Authenticate users with ACS services
CommunicationTokenRefreshOptions	Configure automatic token refresh
CommunicationUserIdentifier	Identify ACS users
PhoneNumberIdentifier	Identify PSTN phone numbers
MicrosoftTeamsUserIdentifier	Identify Teams users
UnknownIdentifier	Generic identifier for unknown types

CommunicationTokenCredential

Static Token (Short-lived Clients)

import com.azure.communication.common.CommunicationTokenCredential;

// Simple static token - no refresh
String userToken = "<user-access-token>";
CommunicationTokenCredential credential = new CommunicationTokenCredential(userToken);

// Use with Chat, Calling, etc.
ChatClient chatClient = new ChatClientBuilder()
    .endpoint("https://<resource>.communication.azure.com")
    .credential(credential)
    .buildClient();

Proactive Token Refresh (Long-lived Clients)

import com.azure.communication.common.CommunicationTokenRefreshOptions;
import java.util.concurrent.Callable;

// Token refresher callback - called when token is about to expire
Callable<String> tokenRefresher = () -> {
    // Call your server to get a fresh token
    return fetchNewTokenFromServer();
};

// With proactive refresh
CommunicationTokenRefreshOptions refreshOptions = new CommunicationTokenRefreshOptions(tokenRefresher)
    .setRefreshProactively(true)      // Refresh before expiry
    .setInitialToken(currentToken);    // Optional initial token

CommunicationTokenCredential credential = new CommunicationTokenCredential(refreshOptions);

Async Token Refresh

import java.util.concurrent.CompletableFuture;

// Async token fetcher
Callable<String> asyncRefresher = () -> {
    CompletableFuture<String> future = fetchTokenAsync();
    return future.get();  // Block until token is available
};

CommunicationTokenRefreshOptions options = new CommunicationTokenRefreshOptions(asyncRefresher)
    .setRefreshProactively(true);

CommunicationTokenCredential credential = new CommunicationTokenCredential(options);

Entra ID (Azure AD) Authentication

import com.azure.identity.InteractiveBrowserCredentialBuilder;
import com.azure.communication.common.EntraCommunicationTokenCredentialOptions;
import java.util.Arrays;
import java.util.List;

// For Teams Phone Extensibility
InteractiveBrowserCredential entraCredential = new InteractiveBrowserCredentialBuilder()
    .clientId("<your-client-id>")
    .tenantId("<your-tenant-id>")
    .redirectUrl("<your-redirect-uri>")
    .build();

String resourceEndpoint = "https://<resource>.communication.azure.com";
List<String> scopes = Arrays.asList(
    "https://auth.msft.communication.azure.com/TeamsExtension.ManageCalls"
);

EntraCommunicationTokenCredentialOptions entraOptions = 
    new EntraCommunicationTokenCredentialOptions(entraCredential, resourceEndpoint)
        .setScopes(scopes);

CommunicationTokenCredential credential = new CommunicationTokenCredential(entraOptions);

Communication Identifiers

CommunicationUserIdentifier

import com.azure.communication.common.CommunicationUserIdentifier;

// Create identifier for ACS user
CommunicationUserIdentifier user = new CommunicationUserIdentifier("8:acs:resource-id_user-id");

// Get raw ID
String rawId = user.getId();

PhoneNumberIdentifier

import com.azure.communication.common.PhoneNumberIdentifier;

// E.164 format phone number
PhoneNumberIdentifier phone = new PhoneNumberIdentifier("+14255551234");

String phoneNumber = phone.getPhoneNumber();  // "+14255551234"
String rawId = phone.getRawId();              // "4:+14255551234"

MicrosoftTeamsUserIdentifier

import com.azure.communication.common.MicrosoftTeamsUserIdentifier;

// Teams user identifier
MicrosoftTeamsUserIdentifier teamsUser = new MicrosoftTeamsUserIdentifier("<teams-user-id>")
    .setCloudEnvironment(CommunicationCloudEnvironment.PUBLIC);

// For anonymous Teams users
MicrosoftTeamsUserIdentifier anonymousTeamsUser = new MicrosoftTeamsUserIdentifier("<teams-user-id>")
    .setAnonymous(true);

UnknownIdentifier

import com.azure.communication.common.UnknownIdentifier;

// For identifiers of unknown type
UnknownIdentifier unknown = new UnknownIdentifier("some-raw-id");

Identifier Parsing

import com.azure.communication.common.CommunicationIdentifier;
import com.azure.communication.common.CommunicationIdentifierModel;

// Parse raw ID to appropriate type
public CommunicationIdentifier parseIdentifier(String rawId) {
    if (rawId.startsWith("8:acs:")) {
        return new CommunicationUserIdentifier(rawId);
    } else if (rawId.startsWith("4:")) {
        String phone = rawId.substring(2);
        return new PhoneNumberIdentifier(phone);
    } else if (rawId.startsWith("8:orgid:")) {
        String teamsId = rawId.substring(8);
        return new MicrosoftTeamsUserIdentifier(teamsId);
    } else {
        return new UnknownIdentifier(rawId);
    }
}

Type Checking Identifiers

import com.azure.communication.common.CommunicationIdentifier;

public void processIdentifier(CommunicationIdentifier identifier) {
    if (identifier instanceof CommunicationUserIdentifier) {
        CommunicationUserIdentifier user = (CommunicationUserIdentifier) identifier;
        System.out.println("ACS User: " + user.getId());
        
    } else if (identifier instanceof PhoneNumberIdentifier) {
        PhoneNumberIdentifier phone = (PhoneNumberIdentifier) identifier;
        System.out.println("Phone: " + phone.getPhoneNumber());
        
    } else if (identifier instanceof MicrosoftTeamsUserIdentifier) {
        MicrosoftTeamsUserIdentifier teams = (MicrosoftTeamsUserIdentifier) identifier;
        System.out.println("Teams User: " + teams.getUserId());
        System.out.println("Anonymous: " + teams.isAnonymous());
        
    } else if (identifier instanceof UnknownIdentifier) {
        UnknownIdentifier unknown = (UnknownIdentifier) identifier;
        System.out.println("Unknown: " + unknown.getId());
    }
}

Token Access

import com.azure.core.credential.AccessToken;

// Get current token (for debugging/logging - don't expose!)
CommunicationTokenCredential credential = new CommunicationTokenCredential(token);

// Sync access
AccessToken accessToken = credential.getToken();
System.out.println("Token expires: " + accessToken.getExpiresAt());

// Async access
credential.getTokenAsync()
    .subscribe(token -> {
        System.out.println("Token: " + token.getToken().substring(0, 20) + "...");
        System.out.println("Expires: " + token.getExpiresAt());
    });

Dispose Credential

// Clean up when done
credential.close();

// Or use try-with-resources
try (CommunicationTokenCredential cred = new CommunicationTokenCredential(options)) {
    // Use credential
    chatClient.doSomething();
}

Cloud Environments

import com.azure.communication.common.CommunicationCloudEnvironment;

// Available environments
CommunicationCloudEnvironment publicCloud = CommunicationCloudEnvironment.PUBLIC;
CommunicationCloudEnvironment govCloud = CommunicationCloudEnvironment.GCCH;
CommunicationCloudEnvironment dodCloud = CommunicationCloudEnvironment.DOD;

// Set on Teams identifier
MicrosoftTeamsUserIdentifier teamsUser = new MicrosoftTeamsUserIdentifier("<user-id>")
    .setCloudEnvironment(CommunicationCloudEnvironment.GCCH);

Environment Variables

AZURE_COMMUNICATION_ENDPOINT=https://<resource>.communication.azure.com
AZURE_COMMUNICATION_USER_TOKEN=<user-access-token>

Best Practices

1. Proactive Refresh - Always use setRefreshProactively(true) for long-lived clients
2. Token Security - Never log or expose full tokens
3. Close Credentials - Dispose of credentials when no longer needed
4. Error Handling - Handle token refresh failures gracefully
5. Identifier Types - Use specific identifier types, not raw strings

Common Usage Patterns

// Pattern: Create credential for Chat/Calling client
public ChatClient createChatClient(String token, String endpoint) {
    CommunicationTokenRefreshOptions refreshOptions = 
        new CommunicationTokenRefreshOptions(this::refreshToken)
            .setRefreshProactively(true)
            .setInitialToken(token);
    
    CommunicationTokenCredential credential = 
        new CommunicationTokenCredential(refreshOptions);
    
    return new ChatClientBuilder()
        .endpoint(endpoint)
        .credential(credential)
        .buildClient();
}

private String refreshToken() {
    // Call your token endpoint
    return tokenService.getNewToken();
}

Trigger Phrases

• "ACS authentication", "communication token credential"
• "user access token", "token refresh"
• "CommunicationUserIdentifier", "PhoneNumberIdentifier"
• "Azure Communication Services authentication"