diff --git a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/CodegenVisitor.java b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/CodegenVisitor.java
index f1957e724..a70e18140 100644
--- a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/CodegenVisitor.java
+++ b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/CodegenVisitor.java
@@ -251,7 +251,9 @@ public Void stringShape(StringShape shape) {
@Override
public Void unionShape(UnionShape shape) {
- writers.useShapeWriter(shape, writer -> new UnionGenerator(model, symbolProvider, writer, shape).run());
+ UnionGenerator generator = new UnionGenerator(model, symbolProvider, shape);
+ writers.useShapeWriter(shape, generator::generateUnion);
+ writers.useShapeExportedTestWriter(shape, generator::generateUnionExamples);
return null;
}
diff --git a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/GoDelegator.java b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/GoDelegator.java
index f8dc87a52..10d0c6051 100644
--- a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/GoDelegator.java
+++ b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/GoDelegator.java
@@ -70,7 +70,7 @@ List<SymbolDependency> getDependencies() {
/**
* Gets a previously created writer or creates a new one if needed.
*
- * @param shape Shape to create the writer for.
+ * @param shape Shape to create the writer for.
* @param writerConsumer Consumer that accepts and works with the file.
*/
public void useShapeWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
@@ -81,7 +81,7 @@ public void useShapeWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
/**
* Gets a previously created writer or creates a new one for the a Go test file for the associated shape.
*
- * @param shape Shape to create the writer for.
+ * @param shape Shape to create the writer for.
* @param writerConsumer Consumer that accepts and works with the file.
*/
public void useShapeTestWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
@@ -93,8 +93,31 @@ public void useShapeTestWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
filename = b.toString();
symbol = symbol.toBuilder()
- .definitionFile(filename)
- .build();
+ .definitionFile(filename)
+ .build();
+
+ useShapeWriter(symbol, writerConsumer);
+ }
+
+ /**
+ * Gets a previously created writer or creates a new one for the a Go public package test file for the associated
+ * shape.
+ *
+ * @param shape Shape to create the writer for.
+ * @param writerConsumer Consumer that accepts and works with the file.
+ */
+ public void useShapeExportedTestWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
+ Symbol symbol = symbolProvider.toSymbol(shape);
+ String filename = symbol.getDefinitionFile();
+
+ StringBuilder b = new StringBuilder(filename);
+ b.insert(filename.lastIndexOf(".go"), "_exported_test");
+ filename = b.toString();
+
+ symbol = symbol.toBuilder()
+ .definitionFile(filename)
+ .namespace(symbol.getNamespace() + "_test", symbol.getNamespaceDelimiter())
+ .build();
useShapeWriter(symbol, writerConsumer);
}
@@ -102,7 +125,7 @@ public void useShapeTestWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
/**
* Gets a previously created writer or creates a new one if needed.
*
- * @param symbol symbol to create the writer for.
+ * @param symbol symbol to create the writer for.
* @param writerConsumer Consumer that accepts and works with the file.
*/
private void useShapeWriter(Symbol symbol, Consumer<GoWriter> writerConsumer) {
@@ -121,7 +144,7 @@ private void useShapeWriter(Symbol symbol, Consumer<GoWriter> writerConsumer) {
* Gets a previously created writer or creates a new one if needed
* and adds a new line if the writer already exists.
*
- * @param filename Name of the file to create.
+ * @param filename Name of the file to create.
* @param writerConsumer Consumer that accepts and works with the file.
*/
void useFileWriter(String filename, String namespace, Consumer<GoWriter> writerConsumer) {
diff --git a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/UnionGenerator.java b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/UnionGenerator.java
index a896e7eae..c69dea64f 100644
--- a/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/UnionGenerator.java
+++ b/codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/UnionGenerator.java
@@ -16,6 +16,8 @@
package software.amazon.smithy.go.codegen;
import java.util.Collection;
+import java.util.Set;
+import java.util.TreeSet;
import software.amazon.smithy.codegen.core.Symbol;
import software.amazon.smithy.codegen.core.SymbolProvider;
import software.amazon.smithy.model.Model;
@@ -27,35 +29,44 @@
/**
* Renders unions and type aliases for all their members.
*/
-public class UnionGenerator implements Runnable {
+public class UnionGenerator {
public static final String UNKNOWN_MEMBER_NAME = "UnknownUnionMember";
private final Model model;
private final SymbolProvider symbolProvider;
- private final GoWriter writer;
private final UnionShape shape;
- UnionGenerator(Model model, SymbolProvider symbolProvider, GoWriter writer, UnionShape shape) {
+ UnionGenerator(Model model, SymbolProvider symbolProvider, UnionShape shape) {
this.model = model;
this.symbolProvider = symbolProvider;
- this.writer = writer;
this.shape = shape;
}
- @Override
- public void run() {
+ /**
+ * Generates the Go type definitions for the UnionShape.
+ *
+ * @param writer the writer
+ */
+ public void generateUnion(GoWriter writer) {
Symbol symbol = symbolProvider.toSymbol(shape);
- writer.writeShapeDocs(shape);
+ Collection<MemberShape> memberShapes = shape.getAllMembers().values();
// Creates the parent interface for the union, which only defines a
// non-exported method whose purpose is only to enable satisfying the
// interface.
+ if (writer.writeShapeDocs(shape)) {
+ writer.writeDocs("");
+ }
+ writer.writeDocs("The following types satisfy this interface:");
+ memberShapes.stream().map(symbolProvider::toMemberName).forEach(name -> {
+ writer.write("// " + name);
+ });
writer.openBlock("type $L interface {", "}", symbol.getName(), () -> {
writer.write("is$L()", symbol.getName());
}).write("");
// Create structs for each member that satisfy the interface.
- for (MemberShape member : shape.getAllMembers().values()) {
+ for (MemberShape member : memberShapes) {
Symbol memberSymbol = symbolProvider.toSymbol(member);
String exportedMemberName = symbolProvider.toMemberName(member);
Shape target = model.expectShape(member.getTarget());
@@ -78,6 +89,42 @@ public void run() {
}
}
+ /**
+ * Generates union usage examples for documentation.
+ *
+ * @param writer the writer
+ */
+ public void generateUnionExamples(GoWriter writer) {
+ Symbol symbol = symbolProvider.toSymbol(shape);
+ Set<MemberShape> members = new TreeSet<>(shape.getAllMembers().values());
+
+ writer.openBlock("func Example$L_outputUsage() {", "}", symbol.getName(), () -> {
+ writer.write("var union $P", symbol);
+
+ writer.writeDocs("type switches can be used to check the union value");
+ writer.openBlock("switch v := union.(type) {", "}", () -> {
+ for (MemberShape member : members) {
+ Symbol targetSymbol = symbolProvider.toSymbol(model.expectShape(member.getTarget()));
+ Symbol memberSymbol = SymbolUtils.createValueSymbolBuilder(symbolProvider.toMemberName(member),
+ symbol.getNamespace()).build();
+
+ writer.openBlock("case *$T:", "", memberSymbol, () -> {
+ writer.write("_ = v.Value // Value is $L", targetSymbol.getName());
+ });
+ }
+ writer.addUseImports(SmithyGoDependency.FMT);
+ Symbol unknownUnionMember = SymbolUtils.createPointableSymbolBuilder("UnknownUnionMember",
+ symbol.getNamespace()).build();
+ writer.openBlock("case $P:", "", unknownUnionMember, () -> {
+ writer.write("fmt.Println(\"unknown tag:\", v.Tag)");
+ });
+ writer.openBlock("default:", "", () -> {
+ writer.write("fmt.Println(\"union is nil or unknown type\")");
+ });
+ });
+ });
+ }
+
/**
* Generates a struct for unknown union values that applies to every union in the given set.
*