Improve ConfigData processing code

Refactor `ConfigData` processing code to make it less awkward to
follow.

Prior to this commit the `ConfigDataLocationResolver` would take a
String location and return a `ConfigDataLocation` instance. This was
a little confusing since sometimes we would refer to `location` as the
String value, and sometimes it would be the typed instance. We also
had nowhere sensible to put the `optional:` prefix logic and we needed
to pass a `boolean` parameter to a number of methods. The recently
introduced `Orgin` support also didn't have a good home.

To solve this, `ConfigDataLocation` has been renamed to
`ConfigDataResource`. This frees up `ConfigDataLocation` to be used
as a richer `location` type that holds the String value, the `Orgin`
and provides a home for the `optional:` logic.

This commit also cleans up a few other areas of the code, including
renaming `ResourceConfigData...` to `StandardConfigData...`. It also
introduces a new exception hierarchy for `ConfigDataNotFoundExceptions`.

Closes gh-23711

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-bootstrap-registry/src/main/java/smoketest/bootstrapregistry/external/svn/SubversionConfigDataLoader.java

@@ -36,7 +36,7 @@ import org.springframework.core.env.PropertySource;
  *
  * @author Phillip Webb
  */
-class SubversionConfigDataLoader implements ConfigDataLoader<SubversionConfigDataLocation> {
+class SubversionConfigDataLoader implements ConfigDataLoader<SubversionConfigDataResource> {
 
 	private static final ApplicationListener<BootstrapContextClosedEvent> closeListener = SubversionConfigDataLoader::onBootstrapContextClosed;
 
@@ -50,12 +50,12 @@ class SubversionConfigDataLoader implements ConfigDataLoader<SubversionConfigDat
 	}
 
 	@Override
-	public ConfigData load(ConfigDataLoaderContext context, SubversionConfigDataLocation location)
+	public ConfigData load(ConfigDataLoaderContext context, SubversionConfigDataResource resource)
 			throws IOException, ConfigDataLocationNotFoundException {
 		context.getBootstrapContext().registerIfAbsent(SubversionServerCertificate.class,
-				InstanceSupplier.of(location.getServerCertificate()));
+				InstanceSupplier.of(resource.getServerCertificate()));
 		SubversionClient client = context.getBootstrapContext().get(SubversionClient.class);
-		String loaded = client.load(location.getLocation());
+		String loaded = client.load(resource.getLocation());
 		PropertySource<?> propertySource = new MapPropertySource("svn", Collections.singletonMap("svn", loaded));
 		return new ConfigData(Collections.singleton(propertySource));
 	}

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-bootstrap-registry/src/main/java/smoketest/bootstrapregistry/external/svn/SubversionConfigDataLocationResolver.java

@@ -19,30 +19,33 @@ package smoketest.bootstrapregistry.external.svn;
 import java.util.Collections;
 import java.util.List;
 
+import org.springframework.boot.context.config.ConfigDataLocation;
 import org.springframework.boot.context.config.ConfigDataLocationNotFoundException;
 import org.springframework.boot.context.config.ConfigDataLocationResolver;
 import org.springframework.boot.context.config.ConfigDataLocationResolverContext;
+import org.springframework.boot.context.config.ConfigDataResourceNotFoundException;
 
 /**
  * {@link ConfigDataLocationResolver} for subversion.
  *
  * @author Phillip Webb
  */
-class SubversionConfigDataLocationResolver implements ConfigDataLocationResolver<SubversionConfigDataLocation> {
+class SubversionConfigDataLocationResolver implements ConfigDataLocationResolver<SubversionConfigDataResource> {
 
 	private static final String PREFIX = "svn:";
 
 	@Override
-	public boolean isResolvable(ConfigDataLocationResolverContext context, String location) {
-		return location.startsWith(PREFIX);
+	public boolean isResolvable(ConfigDataLocationResolverContext context, ConfigDataLocation location) {
+		return location.hasPrefix(PREFIX);
 	}
 
 	@Override
-	public List<SubversionConfigDataLocation> resolve(ConfigDataLocationResolverContext context, String location,
-			boolean optional) throws ConfigDataLocationNotFoundException {
+	public List<SubversionConfigDataResource> resolve(ConfigDataLocationResolverContext context,
+			ConfigDataLocation location)
+			throws ConfigDataLocationNotFoundException, ConfigDataResourceNotFoundException {
 		String serverCertificate = context.getBinder().bind("spring.svn.server.certificate", String.class).orElse(null);
 		return Collections.singletonList(
-				new SubversionConfigDataLocation(location.substring(PREFIX.length()), serverCertificate));
+				new SubversionConfigDataResource(location.getNonPrefixedValue(PREFIX), serverCertificate));
 	}
 
 }

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-bootstrap-registry/src/main/java/smoketest/bootstrapregistry/external/svn/SubversionConfigDataResource.java

@@ -16,20 +16,20 @@
 
 package smoketest.bootstrapregistry.external.svn;
 
-import org.springframework.boot.context.config.ConfigDataLocation;
+import org.springframework.boot.context.config.ConfigDataResource;
 
 /**
- * A subversion {@link ConfigDataLocation}.
+ * A subversion {@link ConfigDataResource}.
  *
  * @author Phillip Webb
  */
-class SubversionConfigDataLocation extends ConfigDataLocation {
+class SubversionConfigDataResource extends ConfigDataResource {
 
 	private final String location;
 
 	private final SubversionServerCertificate serverCertificate;
 
-	SubversionConfigDataLocation(String location, String serverCertificate) {
+	SubversionConfigDataResource(String location, String serverCertificate) {
 		this.location = location;
 		this.serverCertificate = SubversionServerCertificate.of(serverCertificate);
 	}
@@ -50,7 +50,7 @@ class SubversionConfigDataLocation extends ConfigDataLocation {
 		if (obj == null || getClass() != obj.getClass()) {
 			return false;
 		}
-		SubversionConfigDataLocation other = (SubversionConfigDataLocation) obj;
+		SubversionConfigDataResource other = (SubversionConfigDataResource) obj;
 		return this.location.equals(other.location);
 	}