com.google.protobuf

Class Internal

java.lang.Object

com.google.protobuf.Internal

public class Internal
extends java.lang.Object

The classes contained within are used internally by the Protocol Buffer library and generated message implementations. They are public only because those generated messages do not reside in the protobuf package. Others should not use this class directly.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Internal.BooleanList A List implementation that avoids boxing the elements into Booleans if possible.
static interface	Internal.DoubleList A List implementation that avoids boxing the elements into Doubles if possible.
static interface	Internal.EnumLite Interface for an enum value or value descriptor, to be used in FieldSet.
static interface	Internal.EnumLiteMap<T extends Internal.EnumLite> Interface for an object which maps integers to Internal.EnumLites.
static interface	Internal.FloatList A List implementation that avoids boxing the elements into Floats if possible.
static interface	Internal.IntList A List implementation that avoids boxing the elements into Integers if possible.
static class	Internal.ListAdapter<F,T> Provides an immutable view of List<T> around a List<F>.
static interface	Internal.LongList A List implementation that avoids boxing the elements into Longs if possible.
static class	Internal.MapAdapter<K,V,RealValue> Wrap around a Map<K, RealValue> and provide a Map<K, V> interface.
static interface	Internal.ProtobufList<E> Extends List to add the capability to make the list immutable and inspect if it is modifiable.

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	EMPTY_BYTE_ARRAY An empty byte array constant used in generated code.
static java.nio.ByteBuffer	EMPTY_BYTE_BUFFER An empty byte array constant used in generated code.
static CodedInputStream	EMPTY_CODED_INPUT_STREAM An empty coded input stream constant used in generated code.
protected static java.nio.charset.Charset	ISO_8859_1
protected static java.nio.charset.Charset	UTF_8

Constructor Summary

Constructors

Constructor and Description
Internal()

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	byteArrayDefaultValue(java.lang.String bytes) Helper called by generated code to construct default values for bytes fields.
static java.nio.ByteBuffer	byteBufferDefaultValue(java.lang.String bytes) Helper called by generated code to construct default values for bytes fields.
static ByteString	bytesDefaultValue(java.lang.String bytes) Helper called by generated code to construct default values for bytes fields.
static java.nio.ByteBuffer	copyByteBuffer(java.nio.ByteBuffer source) Create a new ByteBuffer and copy all the content of source ByteBuffer to the new ByteBuffer.
static boolean	equals(java.util.List<byte[]> a, java.util.List<byte[]> b) Helper method for implementing Message.equals(Object) for bytes field.
static boolean	equalsByteBuffer(java.nio.ByteBuffer a, java.nio.ByteBuffer b) Helper method for implementing Message.equals(Object) for bytes field.
static boolean	equalsByteBuffer(java.util.List<java.nio.ByteBuffer> a, java.util.List<java.nio.ByteBuffer> b) Helper method for implementing Message.equals(Object) for bytes field.
static <T extends MessageLite> T	getDefaultInstance(java.lang.Class<T> clazz)
static int	hashBoolean(boolean b) Helper method for implementing Message.hashCode() for booleans.
static int	hashCode(byte[] bytes) Helper method for implementing Message.hashCode() for bytes field.
static int	hashCode(java.util.List<byte[]> list) Helper method for implementing Message.hashCode() for bytes field.
static int	hashCodeByteBuffer(java.nio.ByteBuffer bytes) Helper method for implementing Message.hashCode() for bytes field.
static int	hashCodeByteBuffer(java.util.List<java.nio.ByteBuffer> list) Helper method for implementing Message.hashCode() for bytes field.
static int	hashEnum(Internal.EnumLite e) Helper method for implementing Message.hashCode() for enums.
static int	hashEnumList(java.util.List<? extends Internal.EnumLite> list) Helper method for implementing Message.hashCode() for enum lists.
static int	hashLong(long n) Helper method for implementing Message.hashCode() for longs.
static boolean	isValidUtf8(byte[] byteArray) Like isValidUtf8(ByteString) but for byte arrays.
static boolean	isValidUtf8(ByteString byteString) Helper called by generated code to determine if a byte array is a valid UTF-8 encoded string such that the original bytes can be converted to a String object and then back to a byte array round tripping the bytes without loss.
static java.lang.String	stringDefaultValue(java.lang.String bytes) Helper called by generated code to construct default values for string fields.
static byte[]	toByteArray(java.lang.String value) Helper method to get the UTF-8 bytes of a string.
static java.lang.String	toStringUtf8(byte[] bytes) Helper method to convert a byte array to a string using UTF-8 encoding.

Methods inherited from class java.lang.Object

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

Field Detail

UTF_8

protected static final java.nio.charset.Charset UTF_8

ISO_8859_1

protected static final java.nio.charset.Charset ISO_8859_1

EMPTY_BYTE_ARRAY

public static final byte[] EMPTY_BYTE_ARRAY

An empty byte array constant used in generated code.

EMPTY_BYTE_BUFFER

public static final java.nio.ByteBuffer EMPTY_BYTE_BUFFER

An empty byte array constant used in generated code.

EMPTY_CODED_INPUT_STREAM

public static final CodedInputStream EMPTY_CODED_INPUT_STREAM

An empty coded input stream constant used in generated code.

Constructor Detail

Internal

public Internal()

Method Detail

stringDefaultValue

public static java.lang.String stringDefaultValue(java.lang.String bytes)

Helper called by generated code to construct default values for string fields.

The protocol compiler does not actually contain a UTF-8 decoder -- it just pushes UTF-8-encoded text around without touching it. The one place where this presents a problem is when generating Java string literals. Unicode characters in the string literal would normally need to be encoded using a Unicode escape sequence, which would require decoding them. To get around this, protoc instead embeds the UTF-8 bytes into the generated code and leaves it to the runtime library to decode them.

It gets worse, though. If protoc just generated a byte array, like: new byte[] {0x12, 0x34, 0x56, 0x78} Java actually generates *code* which allocates an array and then fills in each value. This is much less efficient than just embedding the bytes directly into the bytecode. To get around this, we need another work-around. String literals are embedded directly, so protoc actually generates a string literal corresponding to the bytes. The easiest way to do this is to use the ISO-8859-1 character set, which corresponds to the first 256 characters of the Unicode range. Protoc can then use good old CEscape to generate the string.

So we have a string literal which represents a set of bytes which represents another string. This function -- stringDefaultValue -- converts from the generated string to the string we actually want. The generated code calls this automatically.

bytesDefaultValue

public static ByteString bytesDefaultValue(java.lang.String bytes)

Helper called by generated code to construct default values for bytes fields.

This is a lot like stringDefaultValue(java.lang.String), but for bytes fields. In this case we only need the second of the two hacks -- allowing us to embed raw bytes as a string literal with ISO-8859-1 encoding.

byteArrayDefaultValue

public static byte[] byteArrayDefaultValue(java.lang.String bytes)

Helper called by generated code to construct default values for bytes fields.

This is like bytesDefaultValue(java.lang.String), but returns a byte array.

byteBufferDefaultValue

public static java.nio.ByteBuffer byteBufferDefaultValue(java.lang.String bytes)

Helper called by generated code to construct default values for bytes fields.

This is like bytesDefaultValue(java.lang.String), but returns a ByteBuffer.

copyByteBuffer

public static java.nio.ByteBuffer copyByteBuffer(java.nio.ByteBuffer source)

Create a new ByteBuffer and copy all the content of source ByteBuffer to the new ByteBuffer. The new ByteBuffer's limit and capacity will be source.capacity(), and its position will be 0. Note that the state of source ByteBuffer won't be changed.

isValidUtf8

public static boolean isValidUtf8(ByteString byteString)

Helper called by generated code to determine if a byte array is a valid UTF-8 encoded string such that the original bytes can be converted to a String object and then back to a byte array round tripping the bytes without loss. More precisely, returns true whenever:

   Arrays.equals(byteString.toByteArray(),
     new String(byteString.toByteArray(), "UTF-8").getBytes("UTF-8"))
 

This method rejects "overlong" byte sequences, as well as 3-byte sequences that would map to a surrogate character, in accordance with the restricted definition of UTF-8 introduced in Unicode 3.1. Note that the UTF-8 decoder included in Oracle's JDK has been modified to also reject "overlong" byte sequences, but currently (2011) still accepts 3-byte surrogate character byte sequences.

See the Unicode Standard,
Table 3-6. UTF-8 Bit Distribution,
Table 3-7. Well Formed UTF-8 Byte Sequences.

As of 2011-02, this method simply returns the result of ByteString.isValidUtf8(). Calling that method directly is preferred.

Parameters:

byteString - the string to check

Returns:

whether the byte array is round trippable

isValidUtf8

public static boolean isValidUtf8(byte[] byteArray)

Like isValidUtf8(ByteString) but for byte arrays.

toByteArray

public static byte[] toByteArray(java.lang.String value)

Helper method to get the UTF-8 bytes of a string.

toStringUtf8

public static java.lang.String toStringUtf8(byte[] bytes)

Helper method to convert a byte array to a string using UTF-8 encoding.

hashLong

public static int hashLong(long n)

Helper method for implementing Message.hashCode() for longs.

See Also:

Long.hashCode()

hashBoolean

public static int hashBoolean(boolean b)

Helper method for implementing Message.hashCode() for booleans.

See Also:

Boolean.hashCode()

hashEnum

public static int hashEnum(Internal.EnumLite e)

Helper method for implementing Message.hashCode() for enums.

This is needed because Enum.hashCode() is final, but we need to use the field number as the hash code to ensure compatibility between statically and dynamically generated enum objects.

hashEnumList

public static int hashEnumList(java.util.List<? extends Internal.EnumLite> list)

Helper method for implementing Message.hashCode() for enum lists.

equals

public static boolean equals(java.util.List<byte[]> a,
             java.util.List<byte[]> b)

Helper method for implementing Message.equals(Object) for bytes field.

hashCode

public static int hashCode(java.util.List<byte[]> list)

Helper method for implementing Message.hashCode() for bytes field.

hashCode

public static int hashCode(byte[] bytes)

Helper method for implementing Message.hashCode() for bytes field.

equalsByteBuffer

public static boolean equalsByteBuffer(java.nio.ByteBuffer a,
                       java.nio.ByteBuffer b)

Helper method for implementing Message.equals(Object) for bytes field.

equalsByteBuffer

public static boolean equalsByteBuffer(java.util.List<java.nio.ByteBuffer> a,
                       java.util.List<java.nio.ByteBuffer> b)

Helper method for implementing Message.equals(Object) for bytes field.

hashCodeByteBuffer

public static int hashCodeByteBuffer(java.util.List<java.nio.ByteBuffer> list)

Helper method for implementing Message.hashCode() for bytes field.

hashCodeByteBuffer

public static int hashCodeByteBuffer(java.nio.ByteBuffer bytes)

Helper method for implementing Message.hashCode() for bytes field.

getDefaultInstance

public static <T extends MessageLite> T getDefaultInstance(java.lang.Class<T> clazz)