Adds generic(TypeMirror) method to Domain (#16)

Signed-off-by: Laird Nelson <[email protected]>

Author: ljnelson

README.md

@@ -31,7 +31,7 @@ as a Maven dependency:
     Always check https://search.maven.org/artifact/org.microbean/microbean-construct
     for up-to-date available versions.
   -->
-  <version>0.0.5</version>
+  <version>0.0.8</version>
 </dependency>
 ```
 

src/main/java/org/microbean/construct/Domain.java

@@ -514,6 +514,44 @@ yield switch (e.getKind()) {
     };
   }
 
+  /**
+   * A convenience method that returns {@code true} if and only if the supplied {@link TypeMirror} is declared by an
+   * {@link Element} that {@linkplain #generic(Element) is generic}.
+   *
+   * @param t a {@link TypeMirror}; must not be {@code null}
+   *
+   * @return {@code true} if and only if the supplied {@link TypeMirror} is declared by an {@link Element} that
+   * {@linkplain #generic(Element) is generic}
+   *
+   * @exception NullPointerException if {@code t} is {@code null}
+   *
+   * @see #generic(Element)
+   *
+   * @spec https://docs.oracle.com/javase/specs/jls/se23/html/jls-8.html#jls-8.1.2 Java Language Specification, section
+   * 8.1.2
+   *
+   * @spec https://docs.oracle.com/javase/specs/jls/se23/html/jls-8.html#jls-8.4.4 Java Language Specification, section
+   * 8.4.4
+   *
+   * @spec https://docs.oracle.com/javase/specs/jls/se23/html/jls-8.html#jls-8.8.4 Java Language Specification, section
+   * 8.8.4
+   *
+   * @spec https://docs.oracle.com/javase/specs/jls/se23/html/jls-9.html#jls-9.1.2 Java Language Specification, section
+   * 9.1.2
+   */
+  public default boolean generic(final TypeMirror t) {
+    return switch (t) {
+    case null -> throw new NullPointerException("t");
+    case UniversalType ut -> ut.generic();
+    default -> {
+      try (var lock = this.lock()) {
+        final Element e = this.asElement(t);
+        yield e != null && this.generic(e);
+      }
+    }
+    };
+  }
+
   /**
    * A convenience method that returns {@code true} if and only if the supplied {@link Element} represents the (essentially
    * primordial) {@code java.lang.Object} {@link Element}.

src/main/java/org/microbean/construct/type/UniversalType.java

@@ -159,6 +159,23 @@ public final UniversalType erasure() {
     return t;
   }
 
+  /**
+   * Returns {@code true} if and only if this {@link UniversalType} is declared by a {@linkplain
+   * UniversalElement#generic() generic declaration}.
+   *
+   * @return {@code true} if and only if this {@link UniversalType} is declared by a {@linkplain
+   * UniversalElement#generic() generic declaration}
+   *
+   * @see UniversalElement#generic()
+   *
+   * @spec https://docs.oracle.com/javase/specs/jls/se23/html/jls-8.html#jls-8.1.2 Java Language Specification, section
+   * 8.1.2
+   */
+  public final boolean generic() {
+    final UniversalElement e = this.asElement();
+    return e != null && e.generic();
+  }
+
   @Override // UnionType
   public final List<? extends UniversalType> getAlternatives() {
     return switch (this.getKind()) {