Reduce builder copies using a managed reference

This commit reduces the number of copies builders need to make when
building up immutable objects.

smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/HttpChecksumTrait.java

@@ -15,7 +15,6 @@
 
 package software.amazon.smithy.aws.traits;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Optional;
@@ -26,6 +25,7 @@
 import software.amazon.smithy.model.traits.AbstractTrait;
 import software.amazon.smithy.model.traits.AbstractTraitBuilder;
 import software.amazon.smithy.model.traits.Trait;
+import software.amazon.smithy.utils.BuilderRef;
 import software.amazon.smithy.utils.ListUtils;
 import software.amazon.smithy.utils.SmithyBuilder;
 import software.amazon.smithy.utils.SmithyUnstableApi;
@@ -56,7 +56,7 @@ private HttpChecksumTrait(HttpChecksumTrait.Builder builder) {
         this.requestChecksumRequired = builder.requestChecksumRequired;
         this.requestAlgorithmMember = builder.requestAlgorithmMember;
         this.requestValidationModeMember = builder.requestValidationModeMember;
-        this.responseAlgorithms = ListUtils.copyOf(builder.responseAlgorithms);
+        this.responseAlgorithms = builder.responseAlgorithms.copy();
     }
 
     public static Builder builder() {
@@ -172,7 +172,7 @@ public static final class Builder extends AbstractTraitBuilder<HttpChecksumTrait
         private boolean requestChecksumRequired;
 
         private String requestValidationModeMember;
-        private final List<String> responseAlgorithms = new ArrayList<>();
+        private final BuilderRef<List<String>> responseAlgorithms = BuilderRef.forList();
 
         private Builder() {}
 
@@ -198,12 +198,12 @@ public Builder requestValidationModeMember(String input) {
 
         public Builder responseAlgorithms(List<String> algorithms) {
             this.responseAlgorithms.clear();
-            this.responseAlgorithms.addAll(algorithms);
+            this.responseAlgorithms.get().addAll(algorithms);
             return this;
         }
 
         public Builder addResponseAlgorithm(String algorithm) {
-            this.responseAlgorithms.add(algorithm);
+            this.responseAlgorithms.get().add(algorithm);
             return this;
         }
 

smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/auth/CognitoUserPoolsTrait.java

@@ -15,7 +15,6 @@
 
 package software.amazon.smithy.aws.traits.auth;
 
-import java.util.ArrayList;
 import java.util.List;
 import software.amazon.smithy.model.node.ArrayNode;
 import software.amazon.smithy.model.node.Node;
@@ -25,8 +24,7 @@
 import software.amazon.smithy.model.traits.AbstractTrait;
 import software.amazon.smithy.model.traits.AbstractTraitBuilder;
 import software.amazon.smithy.model.traits.Trait;
-import software.amazon.smithy.utils.ListUtils;
-import software.amazon.smithy.utils.SmithyBuilder;
+import software.amazon.smithy.utils.BuilderRef;
 import software.amazon.smithy.utils.ToSmithyBuilder;
 
 /**
@@ -41,7 +39,7 @@ public final class CognitoUserPoolsTrait extends AbstractTrait implements ToSmit
 
     private CognitoUserPoolsTrait(Builder builder) {
         super(ID, builder.getSourceLocation());
-        this.providerArns = ListUtils.copyOf(SmithyBuilder.requiredState("providerArns", builder.providerArns));
+        this.providerArns = builder.providerArns.copy();
     }
 
     public static final class Provider extends AbstractTrait.Provider {
@@ -90,7 +88,7 @@ protected Node createNode() {
 
     /** Builder for {@link CognitoUserPoolsTrait}. */
     public static final class Builder extends AbstractTraitBuilder<CognitoUserPoolsTrait, Builder> {
-        private final List<String> providerArns = new ArrayList<>();
+        private final BuilderRef<List<String>> providerArns = BuilderRef.forList();
 
         private Builder() {}
 
@@ -107,7 +105,7 @@ public CognitoUserPoolsTrait build() {
          */
         public Builder providerArns(List<String> providerArns) {
             clearProviderArns();
-            this.providerArns.addAll(providerArns);
+            this.providerArns.get().addAll(providerArns);
             return this;
         }
 
@@ -118,7 +116,7 @@ public Builder providerArns(List<String> providerArns) {
          * @return Returns the builder.
          */
         public Builder addProviderArn(String arn) {
-            providerArns.add(arn);
+            providerArns.get().add(arn);
             return this;
         }
 

smithy-aws-traits/src/main/java/software/amazon/smithy/aws/traits/protocols/AwsProtocolTrait.java

@@ -15,15 +15,14 @@
 
 package software.amazon.smithy.aws.traits.protocols;
 
-import java.util.ArrayList;
 import java.util.List;
 import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
 import software.amazon.smithy.model.shapes.ShapeId;
 import software.amazon.smithy.model.traits.AbstractTrait;
 import software.amazon.smithy.model.traits.AbstractTraitBuilder;
 import software.amazon.smithy.model.traits.Trait;
-import software.amazon.smithy.utils.ListUtils;
+import software.amazon.smithy.utils.BuilderRef;
 
 /**
  * Represents a configurable AWS protocol trait.
@@ -42,8 +41,8 @@ public abstract class AwsProtocolTrait extends AbstractTrait {
     // package-private constructor (at least for now)
     AwsProtocolTrait(ShapeId id, Builder<?, ?> builder) {
         super(id, builder.getSourceLocation());
-        http = ListUtils.copyOf(builder.http);
-        eventStreamHttp = ListUtils.copyOf(builder.eventStreamHttp);
+        http = builder.http.copy();
+        eventStreamHttp = builder.eventStreamHttp.copy();
     }
 
     /**
@@ -89,8 +88,8 @@ protected Node createNode() {
      */
     public abstract static class Builder<T extends Trait, B extends Builder> extends AbstractTraitBuilder<T, B> {
 
-        private final List<String> http = new ArrayList<>();
-        private final List<String> eventStreamHttp = new ArrayList<>();
+        private final BuilderRef<List<String>> http = BuilderRef.forList();
+        private final BuilderRef<List<String>> eventStreamHttp = BuilderRef.forList();
 
         /**
          * Sets the list of supported HTTP protocols.
@@ -101,7 +100,7 @@ public abstract static class Builder<T extends Trait, B extends Builder> extends
         @SuppressWarnings("unchecked")
         public B http(List<String> http) {
             this.http.clear();
-            this.http.addAll(http);
+            this.http.get().addAll(http);
             return (B) this;
         }
 
@@ -114,7 +113,7 @@ public B http(List<String> http) {
         @SuppressWarnings("unchecked")
         public B eventStreamHttp(List<String> eventStreamHttp) {
             this.eventStreamHttp.clear();
-            this.eventStreamHttp.addAll(eventStreamHttp);
+            this.eventStreamHttp.get().addAll(eventStreamHttp);
             return (B) this;
         }
 

smithy-build/src/main/java/software/amazon/smithy/build/ProjectionResult.java

@@ -15,18 +15,14 @@
 
 package software.amazon.smithy.build;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import software.amazon.smithy.model.Model;
 import software.amazon.smithy.model.validation.Severity;
 import software.amazon.smithy.model.validation.ValidationEvent;
-import software.amazon.smithy.utils.ListUtils;
-import software.amazon.smithy.utils.MapUtils;
+import software.amazon.smithy.utils.BuilderRef;
 import software.amazon.smithy.utils.SmithyBuilder;
 
 /**
@@ -41,8 +37,8 @@ public final class ProjectionResult {
     private ProjectionResult(Builder builder) {
         this.projectionName = SmithyBuilder.requiredState("projectionName", builder.projectionName);
         this.model = SmithyBuilder.requiredState("model", builder.model);
-        this.events = ListUtils.copyOf(builder.events);
-        this.pluginManifests = MapUtils.copyOf(builder.pluginManifests);
+        this.events = builder.events.copy();
+        this.pluginManifests = builder.pluginManifests.copy();
     }
 
     /**
@@ -115,8 +111,8 @@ public Optional<FileManifest> getPluginManifest(String pluginName) {
     public static final class Builder implements SmithyBuilder<ProjectionResult> {
         private String projectionName;
         private Model model;
-        private final Map<String, FileManifest> pluginManifests = new HashMap<>();
-        private final Collection<ValidationEvent> events = new ArrayList<>();
+        private final BuilderRef<Map<String, FileManifest>> pluginManifests = BuilderRef.forUnorderedMap();
+        private final BuilderRef<List<ValidationEvent>> events = BuilderRef.forList();
 
         @Override
         public ProjectionResult build() {
@@ -153,7 +149,7 @@ public Builder projectionName(String projectionName) {
          * @return Returns the builder.
          */
         public Builder addPluginManifest(String pluginName, FileManifest manifest) {
-            pluginManifests.put(pluginName, manifest);
+            pluginManifests.get().put(pluginName, manifest);
             return this;
         }
 
@@ -164,7 +160,7 @@ public Builder addPluginManifest(String pluginName, FileManifest manifest) {
          * @return Returns the builder.
          */
         public Builder addEvent(ValidationEvent event) {
-            events.add(Objects.requireNonNull(event));
+            events.get().add(Objects.requireNonNull(event));
             return this;
         }
 

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

@@ -63,7 +63,7 @@
 import software.amazon.smithy.model.traits.TraitDefinition;
 import software.amazon.smithy.model.traits.TraitFactory;
 import software.amazon.smithy.model.validation.ValidatorFactory;
-import software.amazon.smithy.utils.MapUtils;
+import software.amazon.smithy.utils.BuilderRef;
 import software.amazon.smithy.utils.SmithyBuilder;
 import software.amazon.smithy.utils.ToSmithyBuilder;
 
@@ -96,8 +96,8 @@ public final class Model implements ToSmithyBuilder<Model> {
     private int hash;
 
     private Model(Builder builder) {
-        shapeMap = MapUtils.copyOf(builder.shapeMap);
-        metadata = builder.metadata.isEmpty() ? MapUtils.of() : MapUtils.copyOf(builder.metadata);
+        shapeMap = builder.shapeMap.copy();
+        metadata = builder.metadata.copy();
     }
 
     /**
@@ -846,24 +846,24 @@ public <T extends KnowledgeIndex> T getKnowledge(Class<T> type, Function<Model,
      * Builder used to create a Model.
      */
     public static final class Builder implements SmithyBuilder<Model> {
-        private final Map<String, Node> metadata = new HashMap<>();
-        private final Map<ShapeId, Shape> shapeMap = new HashMap<>();
+        private final BuilderRef<Map<String, Node>> metadata = BuilderRef.forUnorderedMap();
+        private final BuilderRef<Map<ShapeId, Shape>> shapeMap = BuilderRef.forUnorderedMap();
 
         private Builder() {}
 
         public Builder metadata(Map<String, Node> metadata) {
             clearMetadata();
-            this.metadata.putAll(metadata);
+            this.metadata.get().putAll(metadata);
             return this;
         }
 
         public Builder putMetadataProperty(String key, Node value) {
-            metadata.put(Objects.requireNonNull(key), Objects.requireNonNull(value));
+            metadata.get().put(Objects.requireNonNull(key), Objects.requireNonNull(value));
             return this;
         }
 
         public Builder removeMetadataProperty(String key) {
-            metadata.remove(key);
+            metadata.get().remove(key);
             return this;
         }
 
@@ -887,10 +887,10 @@ public Builder clearMetadata() {
         public Builder addShape(Shape shape) {
             // Members must be added by their containing shapes.
             if (!shape.isMemberShape()) {
-                shapeMap.put(shape.getId(), shape);
+                shapeMap.get().put(shape.getId(), shape);
                 // Automatically add members of the shape.
                 for (MemberShape memberShape : shape.members()) {
-                    shapeMap.put(memberShape.getId(), memberShape);
+                    shapeMap.get().put(memberShape.getId(), memberShape);
                 }
             }
 
@@ -904,7 +904,7 @@ public Builder addShape(Shape shape) {
          * @return Returns the builder.
          */
         public Builder addShapes(Model model) {
-            shapeMap.putAll(model.shapeMap);
+            shapeMap.get().putAll(model.shapeMap);
             return this;
         }
 
@@ -945,13 +945,13 @@ public Builder addShapes(Shape... shapes) {
          * @return Returns the builder.
          */
         public Builder removeShape(ShapeId shapeId) {
-            if (shapeMap.containsKey(shapeId)) {
-                Shape previous = shapeMap.get(shapeId);
-                shapeMap.remove(shapeId);
+            if (shapeMap.hasValue() && shapeMap.peek().containsKey(shapeId)) {
+                Shape previous = shapeMap.peek().get(shapeId);
+                shapeMap.get().remove(shapeId);
 
                 // Automatically remove any members contained in the shape.
                 for (MemberShape memberShape : previous.members()) {
-                    shapeMap.remove(memberShape.getId());
+                    shapeMap.get().remove(memberShape.getId());
                 }
             }
 

smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlNodeParser.java

@@ -15,10 +15,6 @@
 
 package software.amazon.smithy.model.loader;
 
-import java.util.ArrayList;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.function.Consumer;
 import software.amazon.smithy.model.SourceLocation;
 import software.amazon.smithy.model.node.ArrayNode;
@@ -122,7 +118,8 @@ static Node parseTextBlock(IdlModelParser parser) {
     static ObjectNode parseObjectNode(IdlModelParser parser, String parent) {
         parser.increaseNestingLevel();
         SourceLocation location = parser.currentLocation();
-        Map<StringNode, Node> entries = new LinkedHashMap<>();
+        ObjectNode.Builder builder = ObjectNode.builder()
+                .sourceLocation(location);
         parser.expect('{');
         parser.ws();
 
@@ -138,10 +135,10 @@ static ObjectNode parseObjectNode(IdlModelParser parser, String parent) {
                 parser.ws();
                 Node value = parseNode(parser);
                 StringNode keyNode = new StringNode(key, keyLocation);
-                Node previous = entries.put(keyNode, value);
-                if (previous != null) {
+                if (builder.hasMember(key)) {
                     throw parser.syntax("Duplicate member of " + parent + ": '" + keyNode.getValue() + '\'');
                 }
+                builder.withMember(keyNode, value);
                 parser.ws();
                 if (parser.peek() == ',') {
                     parser.skip();
@@ -154,7 +151,7 @@ static ObjectNode parseObjectNode(IdlModelParser parser, String parent) {
 
         parser.expect('}');
         parser.decreaseNestingLevel();
-        return new ObjectNode(entries, location);
+        return builder.build();
     }
 
     static String parseNodeObjectKey(IdlModelParser parser) {
@@ -168,7 +165,8 @@ static String parseNodeObjectKey(IdlModelParser parser) {
     private static ArrayNode parseArrayNode(IdlModelParser parser) {
         parser.increaseNestingLevel();
         SourceLocation location = parser.currentLocation();
-        List<Node> items = new ArrayList<>();
+        ArrayNode.Builder builder = ArrayNode.builder()
+                .sourceLocation(location);
         parser.expect('[');
         parser.ws();
 
@@ -177,7 +175,7 @@ private static ArrayNode parseArrayNode(IdlModelParser parser) {
             if (c == ']') {
                 break;
             } else {
-                items.add(parseNode(parser));
+                builder.withValue(parseNode(parser));
                 parser.ws();
                 if (parser.peek() == ',') {
                     parser.skip();
@@ -190,6 +188,6 @@ private static ArrayNode parseArrayNode(IdlModelParser parser) {
 
         parser.expect(']');
         parser.decreaseNestingLevel();
-        return new ArrayNode(items, location);
+        return builder.build();
     }
 }