[jOOQ/jOOQ#13499] Improve implementation of QualifiedName.hashCode()

jOOQ/src/main/java/org/jooq/impl/AbstractName.java

@@ -362,10 +362,9 @@ implements
     // XXX: Object API
     // ------------------------------------------------------------------------
 
+    // [#13499] Enforce an optimised implementation
     @Override
-    public int hashCode() {
-        return Arrays.hashCode(getName());
-    }
+    public abstract int hashCode();
 
     @Override
     public boolean equals(Object that) {

jOOQ/src/main/java/org/jooq/impl/LazyName.java

@@ -150,4 +150,13 @@ final class LazyName extends AbstractName {
 
 
 
+
+    // ------------------------------------------------------------------------
+    // XXX: Object API
+    // ------------------------------------------------------------------------
+
+    @Override
+    public int hashCode() {
+        return name().hashCode();
+    }
 }

jOOQ/src/main/java/org/jooq/impl/QualifiedName.java

@@ -44,6 +44,8 @@ import static org.jooq.impl.Tools.anyMatch;
 import static org.jooq.impl.Tools.map;
 import static org.jooq.impl.Tools.stringLiteral;
 
+import java.util.function.Supplier;
+
 import org.jooq.Context;
 import org.jooq.Name;
 import org.jooq.tools.StringUtils;
@@ -66,7 +68,7 @@ final class QualifiedName extends AbstractName {
     }
 
     QualifiedName(Name[] qualifiedName) {
-        this.qualifiedName = last(nonEmpty(qualifiedName));
+        this(last(nonEmpty(qualifiedName)));
     }
 
     private QualifiedName(UnqualifiedName[] qualifiedName) {
@@ -251,4 +253,27 @@ final class QualifiedName extends AbstractName {
     public final Name[] parts() {
         return qualifiedName.clone();
     }
+
+    // ------------------------------------------------------------------------
+    // XXX: Object API
+    // ------------------------------------------------------------------------
+
+    // The assumption is that race conditions for the assignment are
+    // acceptable because the computation is idempotent, so memory
+    // barriers or synchronization aren't necessary.
+    private transient Integer hash;
+
+    @Override
+    public int hashCode() {
+        if (hash == null) {
+            int h = 1;
+
+            for (int i = 0; i < qualifiedName.length; i++)
+                h = 31 * h + qualifiedName[i].name.hashCode();
+
+            hash = h;
+        }
+
+        return hash;
+    }
 }

jOOQ/src/main/java/org/jooq/impl/Tools.java

@@ -6371,6 +6371,24 @@ final class Tools {
         return result;
     }
 
+    static final <T> Supplier<T> cached(Supplier<T> s) {
+        return new Supplier<>() {
+
+            // The assumption is that race conditions for the assignment are
+            // acceptable because the computation is idempotent, so memory
+            // barriers or synchronization isn't necessary.
+            transient T cached;
+
+            @Override
+            public T get() {
+                if (cached == null)
+                    cached = s.get();
+
+                return cached;
+            }
+        };
+    }
+
     /**
      * A base implementation for {@link EmbeddableTableField} flattening
      * iterators with a default implementation for {@link Iterator#remove()} for

jOOQ/src/main/java/org/jooq/impl/UnqualifiedName.java

@@ -44,6 +44,8 @@ import static org.jooq.Name.Quoted.UNQUOTED;
 // ...
 import static org.jooq.impl.Tools.stringLiteral;
 
+import java.util.Arrays;
+
 import org.jooq.Context;
 import org.jooq.Name;
 import org.jooq.conf.RenderQuotedNames;
@@ -57,8 +59,8 @@ import org.jooq.tools.StringUtils;
  */
 final class UnqualifiedName extends AbstractName {
 
-    private final String      name;
-    private final Quoted      quoted;
+    final String name;
+    final Quoted quoted;
 
     UnqualifiedName(String name) {
         this(name, DEFAULT);
@@ -160,4 +162,16 @@ final class UnqualifiedName extends AbstractName {
     public final Name[] parts() {
         return new Name[] { this };
     }
+
+    // ------------------------------------------------------------------------
+    // XXX: Object API
+    // ------------------------------------------------------------------------
+
+    @Override
+    public int hashCode() {
+
+        // [#13499] Since QualifiedName and UnqualifiedName can be equal, both
+        //          need the same hashCode() computation
+        return 31 * 1 + name.hashCode();
+    }
 }