validate created identifiers

Author: SpaceWalkerRS

libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java

@@ -4,18 +4,12 @@
 
 public final class NamespacedIdentifier {
 
-	public static NamespacedIdentifier fromMinecraft(String identifier) {
-		return new NamespacedIdentifier("minecraft", identifier);
-	}
-
-	public static NamespacedIdentifier from(String namespace, String identifier) {
-		return new NamespacedIdentifier(namespace, identifier);
-	}
+	public static final char SEPARATOR = ':';
 
 	private final String namespace;
 	private final String identifier;
 
-	private NamespacedIdentifier(String namespace, String identifier) {
+	NamespacedIdentifier(String namespace, String identifier) {
 		this.namespace = namespace;
 		this.identifier = identifier;
 	}
@@ -39,7 +33,7 @@ public int hashCode() {
 
 	@Override
 	public String toString() {
-		return namespace + ":" + identifier;
+		return namespace + SEPARATOR + identifier;
 	}
 
 	public String getNamespace() {

libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifiers.java

@@ -0,0 +1,106 @@
+package net.ornithemc.osl.core.api.util;
+
+import net.ornithemc.osl.core.impl.util.NamespacedIdentifierException;
+
+/**
+ * Utility methods for creating and validating {@link NamespacedIdentifier}s.
+ */
+public final class NamespacedIdentifiers {
+
+	/**
+	 * The {@code minecraft} namespace is used for Vanilla resources and ids.
+	 */
+	public static final String MINECRAFT_NAMESPACE = "minecraft";
+	/**
+	 * The default namespace of {@code NamespacedIdentifier}s.
+	 * It is recommended to use a custom namespace for your own identifiers.
+	 */
+	public static final String DEFAULT_NAMESPACE = MINECRAFT_NAMESPACE;
+
+	/**
+	 * The maximum length of a {@code NamespacedIdentifier}'s namespace string.
+	 */
+	public static final int MAX_LENGTH_NAMESPACE = Integer.MAX_VALUE;
+	/**
+	 * The maximum length of a {@code NamespacedIdentifier} identifier string.
+	 */
+	public static final int MAX_LENGTH_IDENTIFIER = Integer.MAX_VALUE;
+
+	/**
+	 * Construct and validate a {@code NamespacedIdentifier} with the default namespace and the given identifier.
+	 */
+	public static NamespacedIdentifier from(String identifier) {
+		return from(DEFAULT_NAMESPACE, identifier);
+	}
+
+	/**
+	 * Construct and validate a {@code NamespacedIdentifier} from the given namespace and identifier.
+	 */
+	public static NamespacedIdentifier from(String namespace, String identifier) {
+		return new NamespacedIdentifier(
+			validateNamespace(namespace),
+			validateIdentifier(identifier)
+		);
+	}
+
+	/**
+	 * Parse and validate a {@code NamespacedIdentifier} from the given {@code String}.
+	 */
+	public static NamespacedIdentifier parse(String s) {
+		int i = s.indexOf(NamespacedIdentifier.SEPARATOR);
+
+		if (i > 0) {
+			return from(s.substring(0, i), s.substring(i + 1));
+		} else {
+			return from(s.substring(i + 1));
+		}
+	}
+
+	/**
+	 * Check whether the given {@code NamespacedIdentifier} is valid, or throw an exception.
+	 */
+	public static NamespacedIdentifier validate(NamespacedIdentifier id) {
+		try {
+			validateNamespace(id.getNamespace());
+			validateIdentifier(id.getIdentifier());
+
+			return id;
+		} catch (NamespacedIdentifierException e) {
+			throw NamespacedIdentifierException.invalid(id, e);
+		}
+	}
+
+	/**
+	 * Check that the given namespace is valid for a {@code NamespacedIdentifier}.
+	 */
+	public static String validateNamespace(String namespace) {
+		if (namespace == null || namespace.isEmpty()) {
+			throw NamespacedIdentifierException.invalidNamespace(namespace, "null or empty");
+		}
+		if (namespace.length() > MAX_LENGTH_NAMESPACE) {
+			throw NamespacedIdentifierException.invalidNamespace(namespace, "length " + namespace.length() + " is greater than maximum allowed " + MAX_LENGTH_NAMESPACE);
+		}
+		if (!namespace.chars().allMatch(chr -> chr == '-' || chr == '.' || chr == '_' || (chr >= 'a' && chr <= 'z') || (chr >= 'A' && chr <= 'Z') || (chr >= '0' && chr <= '9'))) {
+			throw NamespacedIdentifierException.invalidNamespace(namespace, "contains illegal characters - only [a-zA-Z0-9-._] are allowed");
+		}
+
+		return namespace;
+	}
+
+	/**
+	 * Check that the given identifier is valid for a {@code NamespacedIdentifier}.
+	 */
+	public static String validateIdentifier(String identifier) {
+		if (identifier == null || identifier.isEmpty()) {
+			throw NamespacedIdentifierException.invalidIdentifier(identifier, "null or empty");
+		}
+		if (identifier.length() > MAX_LENGTH_IDENTIFIER) {
+			throw NamespacedIdentifierException.invalidIdentifier(identifier, "length " + identifier.length() + " is greater than maximum allowed " + MAX_LENGTH_IDENTIFIER);
+		}
+		if (!identifier.chars().allMatch(chr -> chr == '-' || chr == '.' || chr == '_' || chr == '/' || (chr >= 'a' && chr <= 'z') || (chr >= 'A' && chr <= 'Z') || (chr >= '0' && chr <= '9'))) {
+			throw NamespacedIdentifierException.invalidIdentifier(identifier, "contains illegal characters - only [a-zA-Z0-9-._/] are allowed");
+		}
+
+		return identifier;
+	}
+}

libraries/core/src/main/java/net/ornithemc/osl/core/impl/util/NamespacedIdentifierException.java

@@ -0,0 +1,31 @@
+package net.ornithemc.osl.core.impl.util;
+
+import net.ornithemc.osl.core.api.util.NamespacedIdentifier;
+
+@SuppressWarnings("serial")
+public class NamespacedIdentifierException extends RuntimeException {
+
+	private NamespacedIdentifierException(String message) {
+		super(message);
+	}
+
+	private NamespacedIdentifierException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public static NamespacedIdentifierException invalid(NamespacedIdentifier id, Throwable cause) {
+		return new NamespacedIdentifierException("\'" + id + "\' is not a valid namespaced identifier", cause);
+	}
+
+	public static NamespacedIdentifierException invalid(NamespacedIdentifier id, String reason) {
+		return new NamespacedIdentifierException("\'" + id + "\' is not a valid namespaced identifier: " + reason);
+	}
+
+	public static NamespacedIdentifierException invalidNamespace(String namespace, String reason) {
+		return new NamespacedIdentifierException("\'" + namespace + "\' is not a valid namespace: " + reason);
+	}
+
+	public static NamespacedIdentifierException invalidIdentifier(String identifier, String reason) {
+		return new NamespacedIdentifierException("\'" + identifier + "\' is not a valid identifier: " + reason);
+	}
+}