[Passpoint] Create an API to get a unique identifier

Create an API to get a unique identifier of a
PasspointConfiguration object.

Bug: 148555465
Test: atest PasspointConfigurationTest
Change-Id: I74ada04d21b1b8df28b78ca4dd91482bf79dc6cc

api/current.txt

@@ -31616,6 +31616,7 @@ package android.net.wifi.hotspot2 {
     method public android.net.wifi.hotspot2.pps.Credential getCredential();
     method public android.net.wifi.hotspot2.pps.HomeSp getHomeSp();
     method public long getSubscriptionExpirationTimeInMillis();
+    method @NonNull public String getUniqueId() throws java.lang.IllegalStateException;
     method public boolean isOsuProvisioned();
     method public void setCredential(android.net.wifi.hotspot2.pps.Credential);
     method public void setHomeSp(android.net.wifi.hotspot2.pps.HomeSp);

wifi/java/android/net/wifi/hotspot2/PasspointConfiguration.java

@@ -19,6 +19,7 @@ package android.net.wifi.hotspot2;
 import static android.net.wifi.WifiConfiguration.METERED_OVERRIDE_NONE;
 import static android.net.wifi.WifiConfiguration.MeteredOverride;
 
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.net.wifi.hotspot2.pps.Credential;
@@ -895,4 +896,18 @@ public final class PasspointConfiguration implements Parcelable {
     public boolean isOsuProvisioned() {
         return getUpdateIdentifier() != Integer.MIN_VALUE;
     }
+
+    /**
+     * Get a unique identifier for a PasspointConfiguration object.
+     *
+     * @return A unique identifier
+     * @throws IllegalStateException if Credential or HomeSP nodes are not initialized
+     */
+    public @NonNull String getUniqueId() throws IllegalStateException {
+        if (mCredential == null || mHomeSp == null || TextUtils.isEmpty(mHomeSp.getFqdn())) {
+            throw new IllegalStateException("Credential or HomeSP are not initialized");
+        }
+
+        return mHomeSp.getFqdn();
+    }
 }

wifi/tests/src/android/net/wifi/hotspot2/PasspointConfigurationTest.java

@@ -18,6 +18,7 @@ package android.net.wifi.hotspot2;
 
 import static android.net.wifi.WifiConfiguration.METERED_OVERRIDE_NONE;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
@@ -364,4 +365,54 @@ public class PasspointConfigurationTest {
         assertTrue(config.validateForR2());
         assertTrue(config.isOsuProvisioned());
     }
+
+    /**
+     * Verify that the unique identifier generated is correct.
+     *
+     * @throws Exception
+     */
+    @Test
+    public void validateUniqueId() throws Exception {
+        PasspointConfiguration config = PasspointTestUtils.createConfig();
+        String uniqueId;
+        uniqueId = config.getUniqueId();
+        assertEquals(uniqueId, config.getHomeSp().getFqdn());
+    }
+
+    /**
+     * Verify that the unique identifier API generates an exception if HomeSP is not initialized.
+     *
+     * @throws Exception
+     */
+    @Test
+    public void validateUniqueIdExceptionWithEmptyHomeSp() throws Exception {
+        PasspointConfiguration config = PasspointTestUtils.createConfig();
+        config.setHomeSp(null);
+        boolean exceptionCaught = false;
+        try {
+            String uniqueId = config.getUniqueId();
+        } catch (IllegalStateException e) {
+            exceptionCaught = true;
+        }
+        assertTrue(exceptionCaught);
+    }
+
+    /**
+     * Verify that the unique identifier API generates an exception if Credential is not
+     * initialized.
+     *
+     * @throws Exception
+     */
+    @Test
+    public void validateUniqueIdExceptionWithEmptyCredential() throws Exception {
+        PasspointConfiguration config = PasspointTestUtils.createConfig();
+        config.setCredential(null);
+        boolean exceptionCaught = false;
+        try {
+            String uniqueId = config.getUniqueId();
+        } catch (IllegalStateException e) {
+            exceptionCaught = true;
+        }
+        assertTrue(exceptionCaught);
+    }
 }