diff --git a/Android.bp b/Android.bp
index 0ca11d3..6910d75 100644
--- a/Android.bp
+++ b/Android.bp
@@ -503,6 +503,7 @@
         "soong-java",
     ],
     srcs: [
+        "sdk/bp.go",
         "sdk/sdk.go",
         "sdk/update.go",
     ],
diff --git a/android/sdk.go b/android/sdk.go
index 73cb256..01e18ed 100644
--- a/android/sdk.go
+++ b/android/sdk.go
@@ -167,16 +167,39 @@
 	// Unzip the supplied zip into the snapshot relative directory destDir.
 	UnzipToSnapshot(zipPath Path, destDir string)
 
-	// Get the AndroidBpFile for the snapshot.
-	AndroidBpFile() GeneratedSnapshotFile
-
-	// Get a versioned name appropriate for the SDK snapshot version being taken.
-	VersionedSdkMemberName(unversionedName string) interface{}
+	// Add a new prebuilt module to the snapshot. The returned module
+	// must be populated with the module type specific properties. The following
+	// properties will be automatically populated.
+	//
+	// * name
+	// * sdk_member_name
+	// * prefer
+	//
+	// This will result in two Soong modules being generated in the Android. One
+	// that is versioned, coupled to the snapshot version and marked as
+	// prefer=true. And one that is not versioned, not marked as prefer=true and
+	// will only be used if the equivalently named non-prebuilt module is not
+	// present.
+	AddPrebuiltModule(name string, moduleType string) BpModule
 }
 
-// Provides support for generating a file, e.g. the Android.bp file.
-type GeneratedSnapshotFile interface {
-	Printfln(format string, args ...interface{})
-	Indent()
-	Dedent()
+// A set of properties for use in a .bp file.
+type BpPropertySet interface {
+	// Add a property, the value can be one of the following types:
+	// * string
+	// * array of the above
+	// * bool
+	// * BpPropertySet
+	//
+	// It is an error is multiples properties with the same name are added.
+	AddProperty(name string, value interface{})
+
+	// Add a property set with the specified name and return so that additional
+	// properties can be added.
+	AddPropertySet(name string) BpPropertySet
+}
+
+// A .bp module definition.
+type BpModule interface {
+	BpPropertySet
 }
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 96c8416..16e6921 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -1979,28 +1979,6 @@
 	snapshotRelativeDir := filepath.Join("java", d.Name()+"_stubs_sources")
 	builder.UnzipToSnapshot(stubsSrcJar, snapshotRelativeDir)
 
-	d.generatePrebuiltStubsSources(builder, snapshotRelativeDir, true)
-
-	// This module is for the case when the source tree for the unversioned module
-	// doesn't exist (i.e. building in an unbundled tree). "prefer:" is set to false
-	// so that this module does not eclipse the unversioned module if it exists.
-	d.generatePrebuiltStubsSources(builder, snapshotRelativeDir, false)
-}
-
-func (d *Droidstubs) generatePrebuiltStubsSources(builder android.SnapshotBuilder, snapshotRelativeDir string, versioned bool) {
-	bp := builder.AndroidBpFile()
-	name := d.Name()
-	bp.Printfln("prebuilt_stubs_sources {")
-	bp.Indent()
-	if versioned {
-		bp.Printfln("name: %q,", builder.VersionedSdkMemberName(name))
-		bp.Printfln("sdk_member_name: %q,", name)
-	} else {
-		bp.Printfln("name: %q,", name)
-		bp.Printfln("prefer: false,")
-	}
-	bp.Printfln("srcs: [%q],", snapshotRelativeDir)
-	bp.Dedent()
-	bp.Printfln("}")
-	bp.Printfln("")
+	pbm := builder.AddPrebuiltModule(sdkModuleContext.OtherModuleName(d), "prebuilt_stubs_sources")
+	pbm.AddProperty("srcs", []string{snapshotRelativeDir})
 }
diff --git a/java/java.go b/java/java.go
index 5cd074a..9c0fcba 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1737,30 +1737,8 @@
 		}
 	}
 
-	j.generateJavaImport(builder, snapshotRelativeJavaLibPath, true)
-
-	// This module is for the case when the source tree for the unversioned module
-	// doesn't exist (i.e. building in an unbundled tree). "prefer:" is set to false
-	// so that this module does not eclipse the unversioned module if it exists.
-	j.generateJavaImport(builder, snapshotRelativeJavaLibPath, false)
-}
-
-func (j *Library) generateJavaImport(builder android.SnapshotBuilder, snapshotRelativeJavaLibPath string, versioned bool) {
-	bp := builder.AndroidBpFile()
-	name := j.Name()
-	bp.Printfln("java_import {")
-	bp.Indent()
-	if versioned {
-		bp.Printfln("name: %q,", builder.VersionedSdkMemberName(name))
-		bp.Printfln("sdk_member_name: %q,", name)
-	} else {
-		bp.Printfln("name: %q,", name)
-		bp.Printfln("prefer: false,")
-	}
-	bp.Printfln("jars: [%q],", snapshotRelativeJavaLibPath)
-	bp.Dedent()
-	bp.Printfln("}")
-	bp.Printfln("")
+	module := builder.AddPrebuiltModule(sdkModuleContext.OtherModuleName(j), "java_import")
+	module.AddProperty("jars", []string{snapshotRelativeJavaLibPath})
 }
 
 // java_library builds and links sources into a `.jar` file for the device, and possibly for the host as well.
diff --git a/sdk/bp.go b/sdk/bp.go
new file mode 100644
index 0000000..19fb70d
--- /dev/null
+++ b/sdk/bp.go
@@ -0,0 +1,141 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sdk
+
+import (
+	"fmt"
+
+	"android/soong/android"
+)
+
+type bpPropertySet struct {
+	properties map[string]interface{}
+	order      []string
+}
+
+var _ android.BpPropertySet = (*bpPropertySet)(nil)
+
+func (s *bpPropertySet) init() {
+	s.properties = make(map[string]interface{})
+}
+
+func (s *bpPropertySet) AddProperty(name string, value interface{}) {
+	if s.properties[name] != nil {
+		panic("Property %q already exists in property set")
+	}
+
+	s.properties[name] = value
+	s.order = append(s.order, name)
+}
+
+func (s *bpPropertySet) AddPropertySet(name string) android.BpPropertySet {
+	set := &bpPropertySet{}
+	set.init()
+	s.AddProperty(name, set)
+	return set
+}
+
+func (s *bpPropertySet) getValue(name string) interface{} {
+	return s.properties[name]
+}
+
+func (s *bpPropertySet) copy() bpPropertySet {
+	propertiesCopy := make(map[string]interface{})
+	for p, v := range s.properties {
+		propertiesCopy[p] = v
+	}
+
+	return bpPropertySet{
+		properties: propertiesCopy,
+		order:      append([]string(nil), s.order...),
+	}
+}
+
+func (s *bpPropertySet) setProperty(name string, value interface{}) {
+	if s.properties[name] == nil {
+		s.AddProperty(name, value)
+	} else {
+		s.properties[name] = value
+	}
+}
+
+func (s *bpPropertySet) insertAfter(position string, name string, value interface{}) {
+	if s.properties[name] != nil {
+		panic("Property %q already exists in property set")
+	}
+
+	// Add the name to the end of the order, to ensure it has necessary capacity
+	// and to handle the case when the position does not exist.
+	s.order = append(s.order, name)
+
+	// Search through the order for the item that matches supplied position. If
+	// found then insert the name of the new property after it.
+	for i, v := range s.order {
+		if v == position {
+			// Copy the items after the one where the new property should be inserted.
+			copy(s.order[i+2:], s.order[i+1:])
+			// Insert the item in the list.
+			s.order[i+1] = name
+		}
+	}
+
+	s.properties[name] = value
+}
+
+type bpModule struct {
+	bpPropertySet
+	moduleType string
+}
+
+var _ android.BpModule = (*bpModule)(nil)
+
+func (m *bpModule) copy() *bpModule {
+	return &bpModule{
+		bpPropertySet: m.bpPropertySet.copy(),
+		moduleType:    m.moduleType,
+	}
+}
+
+// A .bp file
+type bpFile struct {
+	modules map[string]*bpModule
+	order   []*bpModule
+}
+
+// Add a module.
+//
+// The module must have had its "name" property set to a string value that
+// is unique within this file.
+func (f *bpFile) AddModule(module android.BpModule) {
+	m := module.(*bpModule)
+	if name, ok := m.getValue("name").(string); ok {
+		if f.modules[name] != nil {
+			panic(fmt.Sprintf("Module %q already exists in bp file", name))
+		}
+
+		f.modules[name] = m
+		f.order = append(f.order, m)
+	} else {
+		panic("Module does not have a name property, or it is not a string")
+	}
+}
+
+func (f *bpFile) newModule(moduleType string) *bpModule {
+	module := &bpModule{
+		moduleType: moduleType,
+	}
+	(&module.bpPropertySet).init()
+	return module
+}
diff --git a/sdk/sdk_test.go b/sdk/sdk_test.go
index 1bbd286..8def1d8 100644
--- a/sdk/sdk_test.go
+++ b/sdk/sdk_test.go
@@ -544,15 +544,9 @@
 
 sdk_snapshot {
     name: "mysdk@current",
-    java_libs: [
-        "mysdk_myjavalib@current",
-    ],
-    stubs_sources: [
-        "mysdk_myjavaapistubs@current",
-    ],
-    native_shared_libs: [
-        "mysdk_mynativelib@current",
-    ],
+    java_libs: ["mysdk_myjavalib@current"],
+    stubs_sources: ["mysdk_myjavaapistubs@current"],
+    native_shared_libs: ["mysdk_mynativelib@current"],
 }
 
 `)
diff --git a/sdk/update.go b/sdk/update.go
index 000d200..3bd6336 100644
--- a/sdk/update.go
+++ b/sdk/update.go
@@ -17,6 +17,7 @@
 import (
 	"fmt"
 	"path/filepath"
+	"reflect"
 	"strings"
 
 	"github.com/google/blueprint/proptools"
@@ -28,34 +29,37 @@
 
 var pctx = android.NewPackageContext("android/soong/sdk")
 
-// generatedFile abstracts operations for writing contents into a file and emit a build rule
-// for the file.
-type generatedFile struct {
-	path        android.OutputPath
+type generatedContents struct {
 	content     strings.Builder
 	indentLevel int
 }
 
+// generatedFile abstracts operations for writing contents into a file and emit a build rule
+// for the file.
+type generatedFile struct {
+	generatedContents
+	path android.OutputPath
+}
+
 func newGeneratedFile(ctx android.ModuleContext, path ...string) *generatedFile {
 	return &generatedFile{
-		path:        android.PathForModuleOut(ctx, path...).OutputPath,
-		indentLevel: 0,
+		path: android.PathForModuleOut(ctx, path...).OutputPath,
 	}
 }
 
-func (gf *generatedFile) Indent() {
-	gf.indentLevel++
+func (gc *generatedContents) Indent() {
+	gc.indentLevel++
 }
 
-func (gf *generatedFile) Dedent() {
-	gf.indentLevel--
+func (gc *generatedContents) Dedent() {
+	gc.indentLevel--
 }
 
-func (gf *generatedFile) Printfln(format string, args ...interface{}) {
+func (gc *generatedContents) Printfln(format string, args ...interface{}) {
 	// ninja consumes newline characters in rspfile_content. Prevent it by
 	// escaping the backslash in the newline character. The extra backslash
 	// is removed when the rspfile is written to the actual script file
-	fmt.Fprintf(&(gf.content), strings.Repeat("    ", gf.indentLevel)+format+"\\n", args...)
+	fmt.Fprintf(&(gc.content), strings.Repeat("    ", gc.indentLevel)+format+"\\n", args...)
 }
 
 func (gf *generatedFile) build(pctx android.PackageContext, ctx android.BuilderContext, implicits android.Paths) {
@@ -239,15 +243,18 @@
 	snapshotDir := android.PathForModuleOut(ctx, "snapshot")
 
 	bp := newGeneratedFile(ctx, "snapshot", "Android.bp")
-	bp.Printfln("// This is auto-generated. DO NOT EDIT.")
-	bp.Printfln("")
+
+	bpFile := &bpFile{
+		modules: make(map[string]*bpModule),
+	}
 
 	builder := &snapshotBuilder{
-		ctx:           ctx,
-		version:       "current",
-		snapshotDir:   snapshotDir.OutputPath,
-		filesToZip:    []android.Path{bp.path},
-		androidBpFile: bp,
+		ctx:             ctx,
+		version:         "current",
+		snapshotDir:     snapshotDir.OutputPath,
+		filesToZip:      []android.Path{bp.path},
+		bpFile:          bpFile,
+		prebuiltModules: make(map[string]*bpModule),
 	}
 	s.builderForTests = builder
 
@@ -269,41 +276,37 @@
 		buildSharedNativeLibSnapshot(ctx, info, builder)
 	}
 
-	// generate Android.bp
+	for _, unversioned := range builder.prebuiltOrder {
+		// Copy the unversioned module so it can be modified to make it versioned.
+		versioned := unversioned.copy()
+		name := versioned.properties["name"].(string)
+		versioned.setProperty("name", builder.versionedSdkMemberName(name))
+		versioned.insertAfter("name", "sdk_member_name", name)
+		bpFile.AddModule(versioned)
 
-	bp.Printfln("sdk_snapshot {")
-	bp.Indent()
-	bp.Printfln("name: %q,", ctx.ModuleName()+string(android.SdkVersionSeparator)+builder.version)
+		// Set prefer: false - this is not strictly required as that is the default.
+		unversioned.insertAfter("name", "prefer", false)
+		bpFile.AddModule(unversioned)
+	}
+
+	// Create the snapshot module.
+	snapshotName := ctx.ModuleName() + string(android.SdkVersionSeparator) + builder.version
+	snapshotModule := bpFile.newModule("sdk_snapshot")
+	snapshotModule.AddProperty("name", snapshotName)
 	if len(s.properties.Java_libs) > 0 {
-		bp.Printfln("java_libs: [")
-		bp.Indent()
-		for _, m := range s.properties.Java_libs {
-			bp.Printfln("%q,", builder.VersionedSdkMemberName(m))
-		}
-		bp.Dedent()
-		bp.Printfln("],") // java_libs
+		snapshotModule.AddProperty("java_libs", builder.versionedSdkMemberNames(s.properties.Java_libs))
 	}
 	if len(s.properties.Stubs_sources) > 0 {
-		bp.Printfln("stubs_sources: [")
-		bp.Indent()
-		for _, m := range s.properties.Stubs_sources {
-			bp.Printfln("%q,", builder.VersionedSdkMemberName(m))
-		}
-		bp.Dedent()
-		bp.Printfln("],") // stubs_sources
+		snapshotModule.AddProperty("stubs_sources", builder.versionedSdkMemberNames(s.properties.Stubs_sources))
 	}
 	if len(s.properties.Native_shared_libs) > 0 {
-		bp.Printfln("native_shared_libs: [")
-		bp.Indent()
-		for _, m := range s.properties.Native_shared_libs {
-			bp.Printfln("%q,", builder.VersionedSdkMemberName(m))
-		}
-		bp.Dedent()
-		bp.Printfln("],") // native_shared_libs
+		snapshotModule.AddProperty("native_shared_libs", builder.versionedSdkMemberNames(s.properties.Native_shared_libs))
 	}
-	bp.Dedent()
-	bp.Printfln("}") // sdk_snapshot
-	bp.Printfln("")
+	bpFile.AddModule(snapshotModule)
+
+	// generate Android.bp
+	bp = newGeneratedFile(ctx, "snapshot", "Android.bp")
+	generateBpContents(&bp.generatedContents, bpFile)
 
 	bp.build(pctx, ctx, nil)
 
@@ -351,8 +354,61 @@
 	return outputZipFile
 }
 
+func generateBpContents(contents *generatedContents, bpFile *bpFile) {
+	contents.Printfln("// This is auto-generated. DO NOT EDIT.")
+	for _, bpModule := range bpFile.order {
+		contents.Printfln("")
+		contents.Printfln("%s {", bpModule.moduleType)
+		outputPropertySet(contents, &bpModule.bpPropertySet)
+		contents.Printfln("}")
+	}
+	contents.Printfln("")
+}
+
+func outputPropertySet(contents *generatedContents, set *bpPropertySet) {
+	contents.Indent()
+	for _, name := range set.order {
+		value := set.properties[name]
+
+		reflectedValue := reflect.ValueOf(value)
+		t := reflectedValue.Type()
+
+		kind := t.Kind()
+		switch kind {
+		case reflect.Slice:
+			length := reflectedValue.Len()
+			if length > 1 {
+				contents.Printfln("%s: [", name)
+				contents.Indent()
+				for i := 0; i < length; i = i + 1 {
+					contents.Printfln("%q,", reflectedValue.Index(i).Interface())
+				}
+				contents.Dedent()
+				contents.Printfln("],")
+			} else if length == 0 {
+				contents.Printfln("%s: [],", name)
+			} else {
+				contents.Printfln("%s: [%q],", name, reflectedValue.Index(0).Interface())
+			}
+		case reflect.Bool:
+			contents.Printfln("%s: %t,", name, reflectedValue.Bool())
+
+		case reflect.Ptr:
+			contents.Printfln("%s: {", name)
+			outputPropertySet(contents, reflectedValue.Interface().(*bpPropertySet))
+			contents.Printfln("},")
+
+		default:
+			contents.Printfln("%s: %q,", name, value)
+		}
+	}
+	contents.Dedent()
+}
+
 func (s *sdk) GetAndroidBpContentsForTests() string {
-	return s.builderForTests.androidBpFile.content.String()
+	contents := &generatedContents{}
+	generateBpContents(contents, s.builderForTests.bpFile)
+	return contents.content.String()
 }
 
 func buildSharedNativeLibSnapshot(ctx android.ModuleContext, info *nativeLibInfo, builder android.SnapshotBuilder) {
@@ -406,81 +462,57 @@
 		}
 	}
 
-	info.generatePrebuiltLibrary(ctx, builder, true)
-
-	// This module is for the case when the source tree for the unversioned module
-	// doesn't exist (i.e. building in an unbundled tree). "prefer:" is set to false
-	// so that this module does not eclipse the unversioned module if it exists.
-	info.generatePrebuiltLibrary(ctx, builder, false)
+	info.generatePrebuiltLibrary(ctx, builder)
 }
 
-func (info *nativeLibInfo) generatePrebuiltLibrary(ctx android.ModuleContext, builder android.SnapshotBuilder, versioned bool) {
-	bp := builder.AndroidBpFile()
-	bp.Printfln("cc_prebuilt_library_shared {")
-	bp.Indent()
-	name := info.name
-	if versioned {
-		bp.Printfln("name: %q,", builder.VersionedSdkMemberName(name))
-		bp.Printfln("sdk_member_name: %q,", name)
-	} else {
-		bp.Printfln("name: %q,", name)
-		bp.Printfln("prefer: false,")
-	}
+func (info *nativeLibInfo) generatePrebuiltLibrary(ctx android.ModuleContext, builder android.SnapshotBuilder) {
 
 	// a function for emitting include dirs
-	printExportedDirsForNativeLibs := func(lib archSpecificNativeLibInfo, systemInclude bool) {
+	addExportedDirsForNativeLibs := func(lib archSpecificNativeLibInfo, properties android.BpPropertySet, systemInclude bool) {
 		includeDirs := nativeIncludeDirPathsFor(ctx, lib, systemInclude, info.hasArchSpecificFlags)
 		if len(includeDirs) == 0 {
 			return
 		}
+		var propertyName string
 		if !systemInclude {
-			bp.Printfln("export_include_dirs: [")
+			propertyName = "export_include_dirs"
 		} else {
-			bp.Printfln("export_system_include_dirs: [")
+			propertyName = "export_system_include_dirs"
 		}
-		bp.Indent()
-		for _, dir := range includeDirs {
-			bp.Printfln("%q,", dir)
-		}
-		bp.Dedent()
-		bp.Printfln("],")
+		properties.AddProperty(propertyName, includeDirs)
 	}
 
+	pbm := builder.AddPrebuiltModule(info.name, "cc_prebuilt_library_shared")
+
 	if !info.hasArchSpecificFlags {
-		printExportedDirsForNativeLibs(info.archVariants[0], false /*systemInclude*/)
-		printExportedDirsForNativeLibs(info.archVariants[0], true /*systemInclude*/)
+		addExportedDirsForNativeLibs(info.archVariants[0], pbm, false /*systemInclude*/)
+		addExportedDirsForNativeLibs(info.archVariants[0], pbm, true /*systemInclude*/)
 	}
 
-	bp.Printfln("arch: {")
-	bp.Indent()
+	archProperties := pbm.AddPropertySet("arch")
 	for _, av := range info.archVariants {
-		bp.Printfln("%s: {", av.archType)
-		bp.Indent()
-		bp.Printfln("srcs: [%q],", nativeStubFilePathFor(av))
+		archTypeProperties := archProperties.AddPropertySet(av.archType)
+		archTypeProperties.AddProperty("srcs", []string{nativeStubFilePathFor(av)})
 		if info.hasArchSpecificFlags {
 			// export_* properties are added inside the arch: {<arch>: {...}} block
-			printExportedDirsForNativeLibs(av, false /*systemInclude*/)
-			printExportedDirsForNativeLibs(av, true /*systemInclude*/)
+			addExportedDirsForNativeLibs(av, archTypeProperties, false /*systemInclude*/)
+			addExportedDirsForNativeLibs(av, archTypeProperties, true /*systemInclude*/)
 		}
-		bp.Dedent()
-		bp.Printfln("},") // <arch>
 	}
-	bp.Dedent()
-	bp.Printfln("},") // arch
-	bp.Printfln("stl: \"none\",")
-	bp.Printfln("system_shared_libs: [],")
-	bp.Dedent()
-	bp.Printfln("}") // cc_prebuilt_library_shared
-	bp.Printfln("")
+	pbm.AddProperty("stl", "none")
+	pbm.AddProperty("system_shared_libs", []string{})
 }
 
 type snapshotBuilder struct {
-	ctx           android.ModuleContext
-	version       string
-	snapshotDir   android.OutputPath
-	androidBpFile *generatedFile
-	filesToZip    android.Paths
-	zipsToMerge   android.Paths
+	ctx         android.ModuleContext
+	version     string
+	snapshotDir android.OutputPath
+	bpFile      *bpFile
+	filesToZip  android.Paths
+	zipsToMerge android.Paths
+
+	prebuiltModules map[string]*bpModule
+	prebuiltOrder   []*bpModule
 }
 
 func (s *snapshotBuilder) CopyToSnapshot(src android.Path, dest string) {
@@ -512,10 +544,28 @@
 	s.zipsToMerge = append(s.zipsToMerge, tmpZipPath)
 }
 
-func (s *snapshotBuilder) AndroidBpFile() android.GeneratedSnapshotFile {
-	return s.androidBpFile
+func (s *snapshotBuilder) AddPrebuiltModule(name string, moduleType string) android.BpModule {
+	if s.prebuiltModules[name] != nil {
+		panic(fmt.Sprintf("Duplicate module detected, module %s has already been added", name))
+	}
+
+	m := s.bpFile.newModule(moduleType)
+	m.AddProperty("name", name)
+
+	s.prebuiltModules[name] = m
+	s.prebuiltOrder = append(s.prebuiltOrder, m)
+	return m
 }
 
-func (s *snapshotBuilder) VersionedSdkMemberName(unversionedName string) interface{} {
+// Get a versioned name appropriate for the SDK snapshot version being taken.
+func (s *snapshotBuilder) versionedSdkMemberName(unversionedName string) string {
 	return versionedSdkMemberName(s.ctx, unversionedName, s.version)
 }
+
+func (s *snapshotBuilder) versionedSdkMemberNames(members []string) []string {
+	var references []string = nil
+	for _, m := range members {
+		references = append(references, s.versionedSdkMemberName(m))
+	}
+	return references
+}