Refactor hierarchy of shapes in IDL 2

Rather than expose a NamedMembers interface, I think it makes more
sense to just move all member accessors to Shape. This gets rid
of a lot of cruft when trying to deal with different kinds of shapes
(for example, if you want to write something that works with both
structures and unions).

Furthermore, structurallyExclusive only impacts structure shapes.
This fixes an issue where it was implemented to also check enums,
intEnums, and unions.

smithy-model/src/main/java/software/amazon/smithy/model/FromSourceLocation.java

@@ -34,7 +34,7 @@ default SourceLocation getSourceLocation() {
      *
      * @param s1 the first FromSourceLocation to compare.
      * @param s2 the second FromSourceLocation to compare.
-     * @return the value 0 if s1 == s2; a value less than 0 if s1 < s2; and a value greater than 0 if s1 > s2.
+     * @return the value 0 if s1 == s2; a value less than 0 if s1 &lt; s2; and a value greater than 0 if s1 &gt; s2.
      */
     static int compare(FromSourceLocation s1, FromSourceLocation s2) {
         return s1.getSourceLocation().compareTo(s2.getSourceLocation());

smithy-model/src/main/java/software/amazon/smithy/model/shapes/CollectionShape.java

@@ -17,8 +17,8 @@
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Map;
 import java.util.Objects;
-import java.util.Optional;
 import java.util.function.Consumer;
 import software.amazon.smithy.model.SourceLocation;
 import software.amazon.smithy.model.traits.Trait;
@@ -29,10 +29,18 @@
 public abstract class CollectionShape extends Shape {
 
     private final MemberShape member;
+    private transient Map<String, MemberShape> memberMap;
 
     CollectionShape(Builder<?, ?> builder) {
         super(builder, false);
-        member = builder.member != null ? builder.member : getRequiredMixinMember(builder, "member");
+
+        // Get the member from the builder or from any mixins.
+        if (builder.member != null) {
+            member = builder.member;
+        } else {
+            member = getRequiredMixinMember(builder, "member");
+        }
+
         ShapeId expected = getId().withMember("member");
         if (!member.getId().equals(expected)) {
             throw new IllegalArgumentException(String.format(
@@ -51,18 +59,13 @@ public final MemberShape getMember() {
     }
 
     @Override
-    public final Optional<MemberShape> getMember(String name) {
-        return name.equals("member") ? Optional.of(member) : Optional.empty();
-    }
-
-    @Override
-    public Collection<MemberShape> members() {
-        return Collections.singletonList(member);
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        return super.equals(other) && getMember().equals(((CollectionShape) other).getMember());
+    public final Map<String, MemberShape> getAllMembers() {
+        Map<String, MemberShape> members = memberMap;
+        if (members == null) {
+            members = Collections.singletonMap("member", member);
+            memberMap = members;
+        }
+        return members;
     }
 
     /**

smithy-model/src/main/java/software/amazon/smithy/model/shapes/EnumShape.java

@@ -18,7 +18,6 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
@@ -35,15 +34,13 @@
 import software.amazon.smithy.model.traits.UnitTypeTrait;
 import software.amazon.smithy.model.traits.synthetic.SyntheticEnumTrait;
 import software.amazon.smithy.utils.BuilderRef;
-import software.amazon.smithy.utils.ListUtils;
 
-public final class EnumShape extends StringShape implements NamedMembers {
+public final class EnumShape extends StringShape {
 
     private static final Pattern CONVERTABLE_VALUE = Pattern.compile("^[a-zA-Z-_.:/\\s]+[a-zA-Z_0-9-.:/\\s]*$");
     private static final Logger LOGGER = Logger.getLogger(EnumShape.class.getName());
 
     private final Map<String, MemberShape> members;
-    private volatile List<String> memberNames;
     private volatile Map<String, String> enumValues;
 
     private EnumShape(Builder builder) {
@@ -82,58 +79,15 @@ public Map<String, MemberShape> getAllMembers() {
         return members;
     }
 
-    /**
-     * Returns an ordered list of member names based on the order they are
-     * defined in the model, including mixin members.
-     *
-     * @return Returns an immutable list of member names.
-     */
-    @Override
-    public List<String> getMemberNames() {
-        List<String> names = memberNames;
-        if (names == null) {
-            names = ListUtils.copyOf(members.keySet());
-            memberNames = names;
-        }
-
-        return names;
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        if (!super.equals(other)) {
-            return false;
-        }
-
-        // Members are ordered, so do a test on the ordering and their values.
-        EnumShape b = (EnumShape) other;
-        return getMemberNames().equals(b.getMemberNames()) && members.equals(b.members);
-    }
-
     @Override
+    @SuppressWarnings("deprecation")
     public Optional<Trait> findTrait(ShapeId id) {
         if (id.equals(EnumTrait.ID)) {
             return super.findTrait(SyntheticEnumTrait.ID);
         }
         return super.findTrait(id);
     }
 
-    /**
-     * Get a specific member by name.
-     *
-     * @param name Name of the member to retrieve.
-     * @return Returns the optional member.
-     */
-    @Override
-    public Optional<MemberShape> getMember(String name) {
-        return Optional.ofNullable(members.get(name));
-    }
-
-    @Override
-    public Collection<MemberShape> members() {
-        return members.values();
-    }
-
     public static Builder builder() {
         return new Builder();
     }

smithy-model/src/main/java/software/amazon/smithy/model/shapes/IntEnumShape.java

@@ -18,20 +18,17 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
 import software.amazon.smithy.model.SourceException;
 import software.amazon.smithy.model.traits.EnumValueTrait;
 import software.amazon.smithy.model.traits.UnitTypeTrait;
 import software.amazon.smithy.utils.BuilderRef;
-import software.amazon.smithy.utils.ListUtils;
 
-public final class IntEnumShape extends IntegerShape implements NamedMembers {
+public final class IntEnumShape extends IntegerShape {
 
     private final Map<String, MemberShape> members;
-    private volatile List<String> memberNames;
     private volatile Map<String, Integer> enumValues;
 
     private IntEnumShape(Builder builder) {
@@ -70,50 +67,6 @@ public Map<String, MemberShape> getAllMembers() {
         return members;
     }
 
-    /**
-     * Returns an ordered list of member names based on the order they are
-     * defined in the model, including mixin members.
-     *
-     * @return Returns an immutable list of member names.
-     */
-    @Override
-    public List<String> getMemberNames() {
-        List<String> names = memberNames;
-        if (names == null) {
-            names = ListUtils.copyOf(members.keySet());
-            memberNames = names;
-        }
-
-        return names;
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        if (!super.equals(other)) {
-            return false;
-        }
-
-        // Members are ordered, so do a test on the ordering and their values.
-        IntEnumShape b = (IntEnumShape) other;
-        return getMemberNames().equals(b.getMemberNames()) && members.equals(b.members);
-    }
-
-    /**
-     * Get a specific member by name.
-     *
-     * @param name Name of the member to retrieve.
-     * @return Returns the optional member.
-     */
-    @Override
-    public Optional<MemberShape> getMember(String name) {
-        return Optional.ofNullable(members.get(name));
-    }
-
-    @Override
-    public Collection<MemberShape> members() {
-        return members.values();
-    }
-
     public static Builder builder() {
         return new Builder();
     }

smithy-model/src/main/java/software/amazon/smithy/model/shapes/MapShape.java

@@ -15,14 +15,20 @@
 
 package software.amazon.smithy.model.shapes;
 
+import java.util.AbstractMap;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.Consumer;
 import software.amazon.smithy.model.SourceLocation;
 import software.amazon.smithy.model.traits.Trait;
 import software.amazon.smithy.utils.ListUtils;
+import software.amazon.smithy.utils.Pair;
+import software.amazon.smithy.utils.SetUtils;
 import software.amazon.smithy.utils.ToSmithyBuilder;
 
 /**
@@ -32,6 +38,7 @@ public final class MapShape extends Shape implements ToSmithyBuilder<MapShape> {
 
     private final MemberShape key;
     private final MemberShape value;
+    private transient Map<String, MemberShape> memberMap;
 
     private MapShape(Builder builder) {
         super(builder, false);
@@ -83,32 +90,60 @@ public MemberShape getKey() {
     }
 
     @Override
-    public Collection<MemberShape> members() {
-        return ListUtils.of(key, value);
-    }
+    public Map<String, MemberShape> getAllMembers() {
+        Map<String, MemberShape> result = memberMap;
+
+        // Create a two-entry map that only knows about "key" and "value".
+        if (result == null) {
+            result = new AbstractMap<String, MemberShape>() {
+                private transient Set<Entry<String, MemberShape>> entries;
+                private transient List<MemberShape> values;
+
+                @Override
+                public MemberShape get(Object keyName) {
+                    if ("key".equals(keyName)) {
+                        return key;
+                    } else if ("value".equals(keyName)) {
+                        return value;
+                    } else {
+                        return null;
+                    }
+                }
 
-    @Override
-    public Optional<MemberShape> getMember(String name) {
-        switch (name) {
-            case "key":
-                return Optional.of(key);
-            case "value":
-                return Optional.of(value);
-            default:
-                return Optional.empty();
-        }
-    }
+                @Override
+                public boolean containsKey(Object keyName) {
+                    return "key".equals(keyName) || "value".equals(keyName);
+                }
 
-    @Override
-    public boolean equals(Object other) {
-        if (!super.equals(other)) {
-            return false;
-        } else {
-            MapShape otherShape = (MapShape) other;
-            return super.equals(otherShape)
-                    && getKey().equals(otherShape.getKey())
-                    && getValue().equals(((MapShape) other).getValue());
+                @Override
+                public Set<String> keySet() {
+                    return SetUtils.of("key", "value");
+                }
+
+                @Override
+                public Collection<MemberShape> values() {
+                    List<MemberShape> result = values;
+                    if (result == null) {
+                        result = ListUtils.of(key, value);
+                        values = result;
+                    }
+                    return result;
+                }
+
+                @Override
+                public Set<Entry<String, MemberShape>> entrySet() {
+                    Set<Entry<String, MemberShape>> result = entries;
+                    if (result == null) {
+                        result = SetUtils.of(Pair.of("key", key), Pair.of("value", value));
+                        entries = result;
+                    }
+                    return result;
+                }
+            };
+            memberMap = result;
         }
+
+        return result;
     }
 
     /**