Package com.google.protobuf

Class GeneratedMessageV3.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

java.lang.Object

com.google.protobuf.AbstractMessageLite.Builder

com.google.protobuf.AbstractMessage.Builder<BuilderT>

com.google.protobuf.GeneratedMessageV3.Builder<BuilderT>

All Implemented Interfaces:

Message.Builder, MessageLite.Builder, MessageLiteOrBuilder, MessageOrBuilder, Cloneable

Direct Known Subclasses:

Any.Builder, Api.Builder, BoolValue.Builder, BytesValue.Builder, ClientWireProtocol.AttachToQuery.Builder, ClientWireProtocol.Authenticator.Builder, ClientWireProtocol.CancelQuery.Builder, ClientWireProtocol.CancelQueryResponse.Builder, ClientWireProtocol.CheckDataRequest.Builder, ClientWireProtocol.CheckDataResponse.Builder, ClientWireProtocol.ClearCache.Builder, ClientWireProtocol.ClientConnection.Builder, ClientWireProtocol.ClientConnection2.Builder, ClientWireProtocol.ClientConnection2Response.Builder, ClientWireProtocol.ClientConnectionGCM.Builder, ClientWireProtocol.ClientConnectionGCM2.Builder, ClientWireProtocol.ClientConnectionGCM2Response.Builder, ClientWireProtocol.ClientConnectionGCMResponse.Builder, ClientWireProtocol.ClientConnectionRefreshSession.Builder, ClientWireProtocol.ClientConnectionRefreshSessionResponse.Builder, ClientWireProtocol.ClientConnectionRefreshToken.Builder, ClientWireProtocol.ClientConnectionRefreshTokenResponse.Builder, ClientWireProtocol.ClientConnectionResponse.Builder, ClientWireProtocol.ClientConnectionSecurityToken.Builder, ClientWireProtocol.ClientConnectionSecurityTokenResponse.Builder, ClientWireProtocol.ClientConnectionSSO.Builder, ClientWireProtocol.ClientConnectionSSO2.Builder, ClientWireProtocol.ClientConnectionSSO2Response.Builder, ClientWireProtocol.ClientConnectionSSOResponse.Builder, ClientWireProtocol.CloseConnection.Builder, ClientWireProtocol.CloseResultSet.Builder, ClientWireProtocol.CompletedQueriesResponse.Builder, ClientWireProtocol.CompletedQueriesRow.Builder, ClientWireProtocol.ConfirmationResponse.Builder, ClientWireProtocol.ExecuteExplain.Builder, ClientWireProtocol.ExecuteExplainForSpark.Builder, ClientWireProtocol.ExecuteExport.Builder, ClientWireProtocol.ExecuteExportResponse.Builder, ClientWireProtocol.ExecuteInlinePlan.Builder, ClientWireProtocol.ExecutePlan.Builder, ClientWireProtocol.ExecuteQuery.Builder, ClientWireProtocol.ExecuteQueryResponse.Builder, ClientWireProtocol.ExecuteUpdate.Builder, ClientWireProtocol.ExecuteUpdateResponse.Builder, ClientWireProtocol.ExplainPipelineRequest.Builder, ClientWireProtocol.ExplainPipelineResponse.Builder, ClientWireProtocol.ExplainPlan.Builder, ClientWireProtocol.ExplainResponseStringPlan.Builder, ClientWireProtocol.FetchAuthenticators.Builder, ClientWireProtocol.FetchAuthenticatorsResponse.Builder, ClientWireProtocol.FetchData.Builder, ClientWireProtocol.FetchDataResponse.Builder, ClientWireProtocol.FetchMetadata.Builder, ClientWireProtocol.FetchMetadataResponse.Builder, ClientWireProtocol.FetchSystemMetadata.Builder, ClientWireProtocol.FetchSystemMetadataResponse.Builder, ClientWireProtocol.ForceExternal.Builder, ClientWireProtocol.GetSchema.Builder, ClientWireProtocol.GetSchemaResponse.Builder, ClientWireProtocol.KillQuery.Builder, ClientWireProtocol.KillQueryResponse.Builder, ClientWireProtocol.ListPlan.Builder, ClientWireProtocol.ListPlanResponse.Builder, ClientWireProtocol.LocalQueries.Builder, ClientWireProtocol.LocalQueriesResponse.Builder, ClientWireProtocol.OpenIDAuthenticator.Builder, ClientWireProtocol.QueryConcurrencyResponse.Builder, ClientWireProtocol.Request.Builder, ClientWireProtocol.ResultSet.Builder, ClientWireProtocol.SecondaryInterfaceList.Builder, ClientWireProtocol.SecurityToken.Builder, ClientWireProtocol.SessionInfo.Builder, ClientWireProtocol.SetParameter.Builder, ClientWireProtocol.SetParameter.Concurrency.Builder, ClientWireProtocol.SetParameter.ForceExternal.Builder, ClientWireProtocol.SetParameter.MaxTempDiskLimit.Builder, ClientWireProtocol.SetParameter.MemoryTracing.Builder, ClientWireProtocol.SetParameter.Priority.Builder, ClientWireProtocol.SetParameter.PriorityAdjustFactor.Builder, ClientWireProtocol.SetParameter.PriorityAdjustTime.Builder, ClientWireProtocol.SetParameter.ResultSetColumnLimit.Builder, ClientWireProtocol.SetParameter.RowLimit.Builder, ClientWireProtocol.SetParameter.ServiceClassName.Builder, ClientWireProtocol.SetParameter.TimeLimit.Builder, ClientWireProtocol.SetSchema.Builder, ClientWireProtocol.SysQueriesRow.Builder, ClientWireProtocol.SystemWideCompletedQueries.Builder, ClientWireProtocol.SystemWideQueries.Builder, ClientWireProtocol.SystemWideQueriesResponse.Builder, ClientWireProtocol.TestConnection.Builder, DescriptorProtos.DescriptorProto.Builder, DescriptorProtos.DescriptorProto.ExtensionRange.Builder, DescriptorProtos.DescriptorProto.ReservedRange.Builder, DescriptorProtos.EnumDescriptorProto.Builder, DescriptorProtos.EnumDescriptorProto.EnumReservedRange.Builder, DescriptorProtos.EnumValueDescriptorProto.Builder, DescriptorProtos.FieldDescriptorProto.Builder, DescriptorProtos.FileDescriptorProto.Builder, DescriptorProtos.FileDescriptorSet.Builder, DescriptorProtos.GeneratedCodeInfo.Annotation.Builder, DescriptorProtos.GeneratedCodeInfo.Builder, DescriptorProtos.MethodDescriptorProto.Builder, DescriptorProtos.OneofDescriptorProto.Builder, DescriptorProtos.ServiceDescriptorProto.Builder, DescriptorProtos.SourceCodeInfo.Builder, DescriptorProtos.SourceCodeInfo.Location.Builder, DescriptorProtos.UninterpretedOption.Builder, DescriptorProtos.UninterpretedOption.NamePart.Builder, DoubleValue.Builder, Duration.Builder, Empty.Builder, Enum.Builder, EnumValue.Builder, Field.Builder, FieldMask.Builder, FloatValue.Builder, GeneratedMessageV3.ExtendableBuilder, Int32Value.Builder, Int64Value.Builder, ListValue.Builder, Method.Builder, Mixin.Builder, Option.Builder, PluginProtos.CodeGeneratorRequest.Builder, PluginProtos.CodeGeneratorResponse.Builder, PluginProtos.CodeGeneratorResponse.File.Builder, PluginProtos.Version.Builder, ProtocolMetadata.protocolEndpointAddress.Builder, ProtocolMetadata.protocolEndpointAddress.ipv4Address.Builder, ProtocolMetadata.protocolIdentity.anonymousIdentity.Builder, ProtocolMetadata.protocolIdentity.Builder, ProtocolMetadata.protocolIdentity.certFingerprintIdentity.Builder, ProtocolMetadata.protocolIdentity.hostnameIdentity.Builder, ProtocolPrivMessages.protocolPrivAck.Builder, ProtocolPrivMessages.protocolPrivDisableProtocol.Builder, ProtocolPrivMessages.protocolPrivEnableProtocol.Builder, ProtocolPrivMessages.protocolPrivMessage.Builder, ProtocolPrivMessages.protocolPrivNotifyIdentity.Builder, SourceContext.Builder, StringValue.Builder, Struct.Builder, Timestamp.Builder, Type.Builder, UInt32Value.Builder, UInt64Value.Builder, Validator.EnumValidatorOptions.Builder, Validator.OneofValidatorOptions.Builder, Validator.ValidatorOptions.Builder, Value.Builder

Enclosing class:

GeneratedMessageV3

public abstract static class GeneratedMessageV3.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>
extends AbstractMessage.Builder<BuilderT>

Builder class for GeneratedMessageV3.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Builder()
protected	Builder(GeneratedMessageV3.BuilderParent builderParent)

Method Summary

Modifier and Type	Method	Description
BuilderT	addRepeatedField(Descriptors.FieldDescriptor field, Object value)	Like setRepeatedField, but appends the value as a new element.
BuilderT	clear()	Called by the initialization and clear code paths to allow subclasses to reset any of their builtin fields back to the initial values.
BuilderT	clearField(Descriptors.FieldDescriptor field)	Clears the field.
BuilderT	clearOneof(Descriptors.OneofDescriptor oneof)	TODO(jieluo): Clear it when all subclasses have implemented this method.
BuilderT	clone()	Clones the Builder.
Map<Descriptors.FieldDescriptor,Object>	getAllFields()	Returns a collection of all the fields in this message which are set and their corresponding values.
Descriptors.Descriptor	getDescriptorForType()	Get the message's type's descriptor.
Object	getField(Descriptors.FieldDescriptor field)	Obtains the value of the given field, or the default value if it is not set.
Message.Builder	getFieldBuilder(Descriptors.FieldDescriptor field)	Get a nested builder instance for the given field.
Descriptors.FieldDescriptor	getOneofFieldDescriptor(Descriptors.OneofDescriptor oneof)	TODO(jieluo): Clear it when all subclasses have implemented this method.
protected GeneratedMessageV3.BuilderParent	getParentForChildren()	Gets the GeneratedMessageV3.BuilderParent for giving to our children.
Object	getRepeatedField(Descriptors.FieldDescriptor field, int index)	Gets an element of a repeated field.
Message.Builder	getRepeatedFieldBuilder(Descriptors.FieldDescriptor field, int index)	Get a nested builder instance for the given repeated field instance.
int	getRepeatedFieldCount(Descriptors.FieldDescriptor field)	Gets the number of elements of a repeated field.
final UnknownFieldSet	getUnknownFields()	Get the UnknownFieldSet for this message.
protected UnknownFieldSet.Builder	getUnknownFieldSetBuilder()
boolean	hasField(Descriptors.FieldDescriptor field)	Returns true if the given field is set.
boolean	hasOneof(Descriptors.OneofDescriptor oneof)	TODO(jieluo): Clear it when all subclasses have implemented this method.
protected abstract GeneratedMessageV3.FieldAccessorTable	internalGetFieldAccessorTable()	Get the FieldAccessorTable for this type.
protected MapField	internalGetMapField(int fieldNumber)	Gets the map field with the given field number.
protected MapField	internalGetMutableMapField(int fieldNumber)	Like internalGetMapField(int) but return a mutable version.
protected boolean	isClean()	Gets whether invalidations are needed
boolean	isInitialized()	Returns true if all required fields in the message and all embedded messages are set, false otherwise.
protected void	markClean()	Called by the subclass or a builder to notify us that a message was built and may be cached and therefore invalidations are needed.
BuilderT	mergeUnknownFields(UnknownFieldSet unknownFields)	Merge some unknown fields into the UnknownFieldSet for this message.
protected final void	mergeUnknownLengthDelimitedField(int number, ByteString bytes)	Called by generated subclasses to add to the unknown field set.
protected final void	mergeUnknownVarintField(int number, int value)	Called by generated subclasses to add to the unknown field set.
Message.Builder	newBuilderForField(Descriptors.FieldDescriptor field)	Create a builder for messages of the appropriate type for the given field.
protected void	onBuilt()	Called by the subclass when a message is built.
protected final void	onChanged()	Called when a builder or one of its nested children has changed and any parent should be notified of its invalidation.
protected boolean	parseUnknownField(CodedInputStream input, ExtensionRegistryLite extensionRegistry, int tag)	Called by generated subclasses to parse an unknown field.
BuilderT	setField(Descriptors.FieldDescriptor field, Object value)	Sets a field to the given value.
BuilderT	setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value)	Sets an element of a repeated field to the given value.
BuilderT	setUnknownFields(UnknownFieldSet unknownFields)	Set the UnknownFieldSet for this message.
protected void	setUnknownFieldSetBuilder(UnknownFieldSet.Builder builder)
protected BuilderT	setUnknownFieldsProto3(UnknownFieldSet unknownFields)	This method is obsolete, but we must retain it for compatibility with older generated code.

Methods inherited from class com.google.protobuf.AbstractMessage.Builder

findInitializationErrors, getInitializationErrorString, internalMergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, mergeFrom, newUninitializedMessageException, toString

Methods inherited from class com.google.protobuf.AbstractMessageLite.Builder

addAll, addAll, mergeDelimitedFrom, mergeDelimitedFrom, mergeFrom, newUninitializedMessageException

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.google.protobuf.Message.Builder

build, buildPartial, mergeDelimitedFrom, mergeDelimitedFrom

Methods inherited from interface com.google.protobuf.MessageLite.Builder

mergeFrom

Methods inherited from interface com.google.protobuf.MessageOrBuilder

getDefaultInstanceForType

Constructor Details

Builder

protected Builder()

Builder

protected Builder(GeneratedMessageV3.BuilderParent builderParent)

Method Details

onBuilt

protected void onBuilt()

Called by the subclass when a message is built.

markClean

protected void markClean()

Called by the subclass or a builder to notify us that a message was built and may be cached and therefore invalidations are needed.

isClean

protected boolean isClean()

Gets whether invalidations are needed

Returns:

whether invalidations are needed

clone

public BuilderT clone()

Description copied from interface: MessageLite.Builder

Clones the Builder.

Specified by:

clone in interface Message.Builder

Specified by:

clone in interface MessageLite.Builder

Overrides:

clone in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

See Also:

• Object.clone()

clear

public BuilderT clear()

Called by the initialization and clear code paths to allow subclasses to reset any of their builtin fields back to the initial values.

Specified by:

clear in interface Message.Builder

Specified by:

clear in interface MessageLite.Builder

Overrides:

clear in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

internalGetFieldAccessorTable

protected abstract GeneratedMessageV3.FieldAccessorTable internalGetFieldAccessorTable()

Get the FieldAccessorTable for this type. We can't have the message class pass this in to the constructor because of bootstrapping trouble with DescriptorProtos.

getDescriptorForType

public Descriptors.Descriptor getDescriptorForType()

Description copied from interface: Message.Builder

Get the message's type's descriptor. See MessageOrBuilder.getDescriptorForType().

getAllFields

public Map<Descriptors.FieldDescriptor,Object> getAllFields()

Description copied from interface: MessageOrBuilder

Returns a collection of all the fields in this message which are set and their corresponding values. A singular ("required" or "optional") field is set iff hasField() returns true for that field. A "repeated" field is set iff getRepeatedFieldCount() is greater than zero. The values are exactly what would be returned by calling MessageOrBuilder.getField(Descriptors.FieldDescriptor) for each field. The map is guaranteed to be a sorted map, so iterating over it will return fields in order by field number.
If this is for a builder, the returned map may or may not reflect future changes to the builder. Either way, the returned map is itself unmodifiable.

newBuilderForField

public Message.Builder newBuilderForField(Descriptors.FieldDescriptor field)

Description copied from interface: Message.Builder

Create a builder for messages of the appropriate type for the given field. The builder is NOT nested in the current builder. However, messages built with the builder can then be passed to the Message.Builder.setField(Descriptors.FieldDescriptor, Object), Message.Builder.setRepeatedField(Descriptors.FieldDescriptor, int, Object), or Message.Builder.addRepeatedField(Descriptors.FieldDescriptor, Object) method of the current builder.

To obtain a builder nested in the current builder, use Message.Builder.getFieldBuilder(Descriptors.FieldDescriptor) instead.

getFieldBuilder

public Message.Builder getFieldBuilder(Descriptors.FieldDescriptor field)

Description copied from interface: Message.Builder

Get a nested builder instance for the given field.

Normally, we hold a reference to the immutable message object for the message type field. Some implementations (the generated message builders) can also hold a reference to the builder object (a nested builder) for the field.

If the field is already backed up by a nested builder, the nested builder is returned. Otherwise, a new field builder is created and returned. The original message field (if one exists) is merged into the field builder, which is then nested into its parent builder.

Specified by:

getFieldBuilder in interface Message.Builder

Overrides:

getFieldBuilder in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

getRepeatedFieldBuilder

public Message.Builder getRepeatedFieldBuilder(Descriptors.FieldDescriptor field,
 int index)

Description copied from interface: Message.Builder

Get a nested builder instance for the given repeated field instance.

Normally, we hold a reference to the immutable message object for the message type field. Some implementations (the generated message builders) can also hold a reference to the builder object (a nested builder) for the field.

If the field is already backed up by a nested builder, the nested builder is returned. Otherwise, a new field builder is created and returned. The original message field (if one exists) is merged into the field builder, which is then nested into its parent builder.

Specified by:

getRepeatedFieldBuilder in interface Message.Builder

Overrides:

getRepeatedFieldBuilder in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

hasOneof

public boolean hasOneof(Descriptors.OneofDescriptor oneof)

Description copied from class: AbstractMessage.Builder

TODO(jieluo): Clear it when all subclasses have implemented this method.

Specified by:

hasOneof in interface MessageOrBuilder

Overrides:

hasOneof in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

getOneofFieldDescriptor

public Descriptors.FieldDescriptor getOneofFieldDescriptor(Descriptors.OneofDescriptor oneof)

Description copied from class: AbstractMessage.Builder

TODO(jieluo): Clear it when all subclasses have implemented this method.

Specified by:

getOneofFieldDescriptor in interface MessageOrBuilder

Overrides:

getOneofFieldDescriptor in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

hasField

public boolean hasField(Descriptors.FieldDescriptor field)

Description copied from interface: MessageOrBuilder

Returns true if the given field is set. This is exactly equivalent to calling the generated "has" accessor method corresponding to the field.

getField

public Object getField(Descriptors.FieldDescriptor field)

Description copied from interface: MessageOrBuilder

Obtains the value of the given field, or the default value if it is not set. For primitive fields, the boxed primitive value is returned. For enum fields, the EnumValueDescriptor for the value is returned. For embedded message fields, the sub-message is returned. For repeated fields, a java.util.List is returned.

setField

public BuilderT setField(Descriptors.FieldDescriptor field,
 Object value)

Description copied from interface: Message.Builder

Sets a field to the given value. The value must be of the correct type for this field, that is, the same type that MessageOrBuilder.getField(Descriptors.FieldDescriptor) returns.

clearField

public BuilderT clearField(Descriptors.FieldDescriptor field)

Description copied from interface: Message.Builder

Clears the field. This is exactly equivalent to calling the generated "clear" accessor method corresponding to the field.

clearOneof

public BuilderT clearOneof(Descriptors.OneofDescriptor oneof)

Description copied from class: AbstractMessage.Builder

TODO(jieluo): Clear it when all subclasses have implemented this method.

Specified by:

clearOneof in interface Message.Builder

Overrides:

clearOneof in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

getRepeatedFieldCount

public int getRepeatedFieldCount(Descriptors.FieldDescriptor field)

Description copied from interface: MessageOrBuilder

Gets the number of elements of a repeated field. This is exactly equivalent to calling the generated "Count" accessor method corresponding to the field.

getRepeatedField

public Object getRepeatedField(Descriptors.FieldDescriptor field,
 int index)

Description copied from interface: MessageOrBuilder

Gets an element of a repeated field. For primitive fields, the boxed primitive value is returned. For enum fields, the EnumValueDescriptor for the value is returned. For embedded message fields, the sub-message is returned.

setRepeatedField

public BuilderT setRepeatedField(Descriptors.FieldDescriptor field,
 int index,
 Object value)

Description copied from interface: Message.Builder

Sets an element of a repeated field to the given value. The value must be of the correct type for this field; that is, the same type that MessageOrBuilder.getRepeatedField(Descriptors.FieldDescriptor,int) returns.

addRepeatedField

public BuilderT addRepeatedField(Descriptors.FieldDescriptor field,
 Object value)

Description copied from interface: Message.Builder

Like setRepeatedField, but appends the value as a new element.

setUnknownFields

public BuilderT setUnknownFields(UnknownFieldSet unknownFields)

Description copied from interface: Message.Builder

Set the UnknownFieldSet for this message.

setUnknownFieldsProto3

protected BuilderT setUnknownFieldsProto3(UnknownFieldSet unknownFields)

This method is obsolete, but we must retain it for compatibility with older generated code.

mergeUnknownFields

public BuilderT mergeUnknownFields(UnknownFieldSet unknownFields)

Description copied from interface: Message.Builder

Merge some unknown fields into the UnknownFieldSet for this message.

Specified by:

mergeUnknownFields in interface Message.Builder

Overrides:

mergeUnknownFields in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

isInitialized

public boolean isInitialized()

Description copied from interface: MessageLiteOrBuilder

Returns true if all required fields in the message and all embedded messages are set, false otherwise.

See also: MessageOrBuilder.getInitializationErrorString()

getUnknownFields

public final UnknownFieldSet getUnknownFields()

Description copied from interface: MessageOrBuilder

Get the UnknownFieldSet for this message.

parseUnknownField

protected boolean parseUnknownField(CodedInputStream input,
 ExtensionRegistryLite extensionRegistry,
 int tag)
                             throws IOException

Called by generated subclasses to parse an unknown field.

Returns:

true unless the tag is an end-group tag.

Throws:

IOException

mergeUnknownLengthDelimitedField

protected final void mergeUnknownLengthDelimitedField(int number,
 ByteString bytes)

Called by generated subclasses to add to the unknown field set.

mergeUnknownVarintField

protected final void mergeUnknownVarintField(int number,
 int value)

Called by generated subclasses to add to the unknown field set.

getUnknownFieldSetBuilder

protected UnknownFieldSet.Builder getUnknownFieldSetBuilder()

Overrides:

getUnknownFieldSetBuilder in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

setUnknownFieldSetBuilder

protected void setUnknownFieldSetBuilder(UnknownFieldSet.Builder builder)

Overrides:

setUnknownFieldSetBuilder in class AbstractMessage.Builder<BuilderT extends GeneratedMessageV3.Builder<BuilderT>>

getParentForChildren

protected GeneratedMessageV3.BuilderParent getParentForChildren()

Gets the GeneratedMessageV3.BuilderParent for giving to our children.

Returns:

The builder parent for our children.

onChanged

protected final void onChanged()

Called when a builder or one of its nested children has changed and any parent should be notified of its invalidation.

internalGetMapField

protected MapField internalGetMapField(int fieldNumber)

Gets the map field with the given field number. This method should be overridden in the generated message class if the message contains map fields.

Unlike other field types, reflection support for map fields can't be implemented based on generated public API because we need to access a map field as a list in reflection API but the generated API only allows us to access it as a map. This method returns the underlying map field directly and thus enables us to access the map field as a list.

internalGetMutableMapField

protected MapField internalGetMutableMapField(int fieldNumber)

Like internalGetMapField(int) but return a mutable version.