com.threerings.io.Streamer Maven / Gradle / Ivy
//
// $Id: Streamer.java 6652 2011-06-05 18:22:28Z ray $
//
// Narya library - tools for developing networked games
// Copyright (C) 2002-2011 Three Rings Design, Inc., All Rights Reserved
// http://code.google.com/p/narya/
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package com.threerings.io;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.io.IOException;
import com.google.common.base.Defaults;
import com.google.common.base.Objects;
import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.samskivert.util.ArrayUtil;
import com.samskivert.util.ByteEnum;
import com.samskivert.util.ByteEnumUtil;
import com.samskivert.util.ClassUtil;
import com.samskivert.util.QuickSort;
import static com.threerings.NaryaLog.log;
/**
* Handles the streaming of {@link Streamable} instances as well as a set of basic object types
* (see {@link ObjectOutputStream}). An instance of {@link Streamer} is created for each distinct
* class that implements {@link Streamable}. The {@link Streamer} reflects on the streamed class
* and caches the information necessary to efficiently read and write objects of the class in
* question.
*/
public abstract class Streamer
{
/**
* Returns true if the supplied target class can be streamed using a streamer.
*/
public synchronized static boolean isStreamable (Class target)
{
// if we have not yet initialized ourselves, do so now
maybeInit();
// if we already have a streamer, or it's an enum, it's good
if (_streamers.containsKey(target) || target.isEnum()) {
return true;
}
// arrays are streamable, let's check the component type
if (target.isArray()) {
return isStreamable(target.getComponentType());
}
// otherwise it must be Streamable, or an Iterable or Map
return Streamable.class.isAssignableFrom(target) ||
Iterable.class.isAssignableFrom(target) ||
Map.class.isAssignableFrom(target);
}
/**
* Returns the class that should be used when streaming this object. In general that is the
* object's natural class, but for enum values, that might be its declaring class as enums use
* classes in a way that would otherwise pollute our id to class mapping space.
*/
public static Class getStreamerClass (Object object)
{
return (object instanceof Enum) ?
((Enum)object).getDeclaringClass() : object.getClass();
}
/**
* If the specified class is not Streamable and is a Collection type, return the
* most specific supported Collection interface type; otherwise return null.
*/
public static Class getCollectionClass (Class clazz)
{
if (Streamable.class.isAssignableFrom(clazz)) {
// the class is natively streamable, let's ignore it
return null;
}
for (Class collClass : BasicStreamers.CollectionStreamer.SPECIFICITY_ORDER) {
if (collClass.isAssignableFrom(clazz)) {
return collClass;
}
}
return null;
}
/**
* Obtains a {@link Streamer} that can be used to read and write objects of the specified
* target class. {@link Streamer} instances are shared among all {@link ObjectInputStream}s and
* {@link ObjectOutputStream}s.
*
* @param target the class that is desired to be streamed. This should be the result of a call
* to {@link #getStreamerClass} if the caller has an instance they wish to stream.
*
* @throws IOException when a streamer is requested for an object that does not implement
* {@link Streamable} and is not one of the basic object types (@see {@link
* ObjectOutputStream}).
*/
public synchronized static Streamer getStreamer (final Class target)
throws IOException
{
// if we have not yet initialized ourselves, do so now
maybeInit();
Streamer stream = _streamers.get(target);
if (stream == null) {
// Get or create a streamer for the class, and cache it.
// First, see if it's a collection type...
Class collClass = getCollectionClass(target);
if (collClass != null) {
stream = getStreamer(collClass);
// otherwise make sure it's a streamable class
} else if (!isStreamable(target)) {
throw new IOException(
"Requested to stream invalid class '" + target.getName() + "'");
} else {
// create a new streamer for the class
if (ObjectInputStream.STREAM_DEBUG) {
log.info("Creating a streamer for '" + target.getName() + "'.");
}
// create our streamer in a privileged block so that it can introspect on the to be
// streamed class
try {
stream = AccessController.doPrivileged(
new PrivilegedExceptionAction() {
public Streamer run () throws IOException {
return create(target);
}
});
} catch (PrivilegedActionException pae) {
throw (IOException) pae.getCause();
}
}
// cache the streamer by the class type
_streamers.put(target, stream);
}
return stream;
}
/**
* Writes the supplied object to the specified stream.
*
* @param object the instance to be written to the stream.
* @param out the stream to which to write the instance.
* @param useWriter whether or not to use the custom writeObject if one exists.
*/
public abstract void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException;
/**
* Creates a blank object that can subsequently be read by this streamer. Data may be read
* from the input stream as a result of this method (in the case of arrays, the length of the
* array must be read before creating the array).
*/
public abstract Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException;
/**
* Reads and populates the fields of the supplied object from the specified stream.
*
* @param object the instance to be read from the stream.
* @param in the stream from which to read the instance.
* @param useReader whether or not to use the custom readObject if one exists.
*/
public abstract void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException;
@Override
public final String toString ()
{
return toStringHelper().toString();
}
/**
* Overrideable to add more information to this class' toString() representation.
*/
protected Objects.ToStringHelper toStringHelper ()
{
// no extra details in the base class
return Objects.toStringHelper(this);
}
/**
* The constructor used by the basic streamers.
*/
protected Streamer ()
{
}
/**
* Create the appropriate Streamer for a newly-seen class.
*/
protected static Streamer create (Class target)
throws IOException
{
// validate that the class is really streamable
boolean isInner = false, isStatic = Modifier.isStatic(target.getModifiers());
try {
isInner = (target.getDeclaringClass() != null);
} catch (Throwable t) {
log.warning("Failure checking innerness of class",
"class", target.getName(), "error", t);
}
if (isInner && !isStatic) {
throw new IllegalArgumentException(
"Cannot stream non-static inner class: " + target.getName());
}
// create streamers for array types
if (target.isArray()) {
Class componentType = target.getComponentType();
if (Modifier.isFinal(componentType.getModifiers())) {
Streamer delegate = Streamer.getStreamer(componentType);
if (delegate != null) {
return new FinalArrayStreamer(componentType, delegate);
} // else: error, below
} else if (isStreamable(componentType)) {
return new ArrayStreamer(componentType);
}
String errmsg = "Aiya! Streamer created for array type but we have no registered " +
"streamer for the element type [type=" + target.getName() + "]";
throw new RuntimeException(errmsg);
}
// create streamers for enum types
if (target.isEnum()) {
switch (ENUM_POLICY) {
case NAME_WITH_BYTE_ENUM:
case ORDINAL_WITH_BYTE_ENUM:
if (ByteEnum.class.isAssignableFrom(target)) {
return new ByteEnumStreamer(target);
}
break;
default:
// we do not care if it is a ByteEnum, we move on...
break;
}
switch (ENUM_POLICY) {
case NAME_WITH_BYTE_ENUM:
case NAME:
return new NameEnumStreamer(target);
default:
List universe = ImmutableList.copyOf(target.getEnumConstants());
int maxOrdinal = universe.size() - 1;
if (maxOrdinal <= Byte.MAX_VALUE) {
return new ByteOrdEnumStreamer(target, universe);
} else if (maxOrdinal <= Short.MAX_VALUE) {
return new ShortOrdEnumStreamer(target, universe);
} else {
return new IntOrdEnumStreamer(target, universe);
}
}
}
// create Streamers for other types
Method reader = null;
Method writer = null;
try {
reader = target.getMethod(READER_METHOD_NAME, READER_ARGS);
} catch (NoSuchMethodException nsme) {
// nothing to worry about, we just don't have one
}
try {
writer = target.getMethod(WRITER_METHOD_NAME, WRITER_ARGS);
} catch (NoSuchMethodException nsme) {
// nothing to worry about, we just don't have one
}
// if there is no reader and no writer, we can do a simpler thing
if ((reader == null) && (writer == null)) {
return new ClassStreamer(target);
} else {
return new CustomClassStreamer(target, reader, writer);
}
}
/**
* A streamer that streams the fields of a class.
*/
protected static class ClassStreamer extends Streamer
{
/** Constructor. */
protected ClassStreamer (Class target)
{
_target = target;
initConstructor();
_marshallers = createMarshallers();
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
int fcount = _fields.length;
for (int ii = 0; ii < fcount; ii++) {
Field field = _fields[ii];
FieldMarshaller fm = _marshallers[ii];
try {
if (ObjectInputStream.STREAM_DEBUG) {
log.info("Writing field",
"class", _target.getName(), "field", field.getName());
}
fm.writeField(field, object, out);
} catch (Exception e) {
String errmsg = "Failure writing streamable field [class=" + _target.getName() +
", field=" + field.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(e);
}
}
}
@Override
public Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException
{
try {
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Creating object '" + _target.getName() + "'.");
}
return _ctor.newInstance(_ctorArgs);
} catch (InvocationTargetException ite) {
String errmsg = "Error instantiating object [type=" + _target.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(ite.getCause());
} catch (InstantiationException ie) {
String errmsg = "Error instantiating object [type=" + _target.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(ie);
} catch (IllegalAccessException iae) {
String errmsg = "Error instantiating object [type=" + _target.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(iae);
}
}
@Override
public void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException
{
int fcount = _fields.length;
for (int ii = 0; ii < fcount; ii++) {
Field field = _fields[ii];
FieldMarshaller fm = _marshallers[ii];
try {
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Reading field '" + field.getName() + "' " +
"with " + fm + ".");
}
// gracefully deal with objects that have had new fields added to their class
// definition
if (in.available() > 0) {
fm.readField(field, object, in);
} else {
log.info("Streamed instance missing field (probably newly added)",
"class", _target.getName(), "field", field.getName());
}
} catch (Exception e) {
String errmsg = "Failure reading streamable field [class=" + _target.getName() +
", field=" + field.getName() + ", error=" + e + "]";
throw (IOException) new IOException(errmsg).initCause(e);
}
}
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Read object '" + object + "'.");
}
}
/**
* Locates the appropriate constructor for creating instances.
*/
protected void initConstructor ()
{
// if we have a zero argument constructor, we have to use that one
for (Constructor ctor : _target.getDeclaredConstructors()) {
if (ctor.getParameterTypes().length == 0) {
_ctor = ctor;
_ctorArgs = ArrayUtil.EMPTY_OBJECT;
return;
}
}
// otherwise there should be a single non-zero-argument constructor, which we'll call
// with zero-valued arguments at unstreaming time, which will then be overwritten by
// readObject()
Constructor[] ctors = _target.getDeclaredConstructors();
if (ctors.length > 1) {
throw new RuntimeException(
"Streamable closure classes must have either a zero-argument constructor " +
"or a single argument-taking constructor; multiple argument-taking " +
"constructors are not allowed [class=" + _target.getName() + "]");
}
_ctor = ctors[0];
_ctor.setAccessible(true);
// we pass bogus arguments to it (because unstreaming will overwrite our bogus
// values with the real values)
Class[] ptypes = _ctor.getParameterTypes();
_ctorArgs = new Object[ptypes.length];
for (int ii = 0; ii < ptypes.length; ii++) {
// this will be the appropriately typed zero, or null
_ctorArgs[ii] = Defaults.defaultValue(ptypes[ii]);
}
}
/**
* Creates and returns the reading and writing marshallers.
*/
protected FieldMarshaller[] createMarshallers ()
{
// reflect on all the object's fields
List fields = Lists.newArrayList();
// this will read all non-static, non-transient fields into our fields list
ClassUtil.getFields(_target, fields);
// Checks whether or not we should stream the fields in alphabetical order.
// This ensures cross-JVM compatibility since Class.getDeclaredFields() does not
// define an order. Due to legacy issues, this is not used by default.
if (SORT_FIELDS) {
QuickSort.sort(fields, FIELD_NAME_ORDER);
}
// remove all marked with NotStreamable, and if we're a streamable closure, remove any
// anonymous enclosing class reference
Predicate filter = Streamable.Closure.class.isAssignableFrom(_target) ?
IS_STREAMCLOSURE : IS_STREAMABLE;
_fields = Iterables.toArray(Iterables.filter(fields, filter), Field.class);
int fcount = _fields.length;
// obtain field marshallers for all of our fields
FieldMarshaller[] marshallers = new FieldMarshaller[fcount];
for (int ii = 0; ii < fcount; ii++) {
marshallers[ii] = FieldMarshaller.getFieldMarshaller(_fields[ii]);
if (marshallers[ii] == null) {
String errmsg = "Unable to marshall field [class=" + _target.getName() +
", field=" + _fields[ii].getName() +
", type=" + _fields[ii].getType().getName() + "]";
throw new RuntimeException(errmsg);
}
if (ObjectInputStream.STREAM_DEBUG) {
log.info("Using " + marshallers[ii] + " for " + _target.getName() + "." +
_fields[ii].getName() + ".");
}
}
return marshallers;
}
@Override
protected Objects.ToStringHelper toStringHelper ()
{
return super.toStringHelper()
.add("target", _target.getName())
.add("fcount", (_fields == null) ? 0 : _fields.length);
}
/** The class for which this streamer instance is configured. */
protected Class _target;
/** The constructor we use to create instances. */
protected Constructor _ctor;
/** The arguments we pass to said constructor (empty or all null/zero). */
protected Object[] _ctorArgs;
/** The non-transient, non-static public fields that we will stream when requested. */
protected Field[] _fields;
/** Field marshallers for each field that will be read or written in our objects. */
protected FieldMarshaller[] _marshallers;
} // end: static class ClassStreamer
/**
* Extends basic class streaming with support for customized streaming.
*/
protected static class CustomClassStreamer extends ClassStreamer
{
/** Constructor. */
protected CustomClassStreamer (Class target, Method reader, Method writer)
{
super(target);
_reader = reader;
_writer = writer;
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
// if we're supposed to and one exists, use the writer method
if (useWriter && _writer != null) {
try {
if (ObjectInputStream.STREAM_DEBUG) {
log.info("Writing with writer", "class", _target.getName());
}
_writer.invoke(object, new Object[] { out });
} catch (Throwable t) {
if (t instanceof InvocationTargetException) {
t = ((InvocationTargetException)t).getTargetException();
}
if (t instanceof IOException) {
throw (IOException)t;
}
String errmsg = "Failure invoking streamable writer " +
"[class=" + _target.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(t);
}
return;
}
// otherwise, ensure the marshallers are initialized and call super
if (_marshallers == null) {
// this can race with other threads, but the worst that can happen is that the work
// done in createMarshallers() is duplicated
_marshallers = super.createMarshallers();
}
super.writeObject(object, out, useWriter);
}
@Override
public void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException
{
// if we're supposed to and one exists, use the reader method
if (useReader && _reader != null) {
try {
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Reading with reader '" + _target.getName() +
"." + _reader.getName() + "()'.");
}
_reader.invoke(object, new Object[] { in });
} catch (Throwable t) {
if (t instanceof InvocationTargetException) {
t = ((InvocationTargetException)t).getTargetException();
}
if (t instanceof IOException) {
throw (IOException)t;
}
String errmsg = "Failure invoking streamable reader " +
"[class=" + _target.getName() + "]";
throw (IOException) new IOException(errmsg).initCause(t);
}
return;
}
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Reading '" + _target.getName() + "'.");
}
// otherwise, ensure the marshallers are iniitalized and call super
if (_marshallers == null) {
// this can race with other threads, but the worst that can happen is that the work
// done in createMarshallers() is duplicated
_marshallers = super.createMarshallers();
}
super.readObject(object, in, useReader);
}
@Override
protected FieldMarshaller[] createMarshallers ()
{
// we will lazy-initialize the marshallers only if needed, so we don't call super
// (It's possible there is only a writer method, but the object is never read from
// clients, so don't get cute and set up the marshallers at construct time if one of
// the methods is null).
return null;
}
@Override
protected Objects.ToStringHelper toStringHelper ()
{
return super.toStringHelper()
.add("reader", _reader)
.add("writer", _writer);
}
/** A reference to the readObject method if one is defined by our target. */
protected Method _reader;
/** A reference to the writeObject method if one is defined by our target. */
protected Method _writer;
} // end: static class CustomClassStreamer
/**
* A streamer for array types.
*/
protected static class ArrayStreamer extends Streamer
{
/** Constructor. */
protected ArrayStreamer (Class componentType)
{
_componentType = componentType;
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
int length = Array.getLength(object);
out.writeInt(length);
// write each array element with its own class identifier
// because it could be any derived class of the array element type
for (int ii = 0; ii < length; ii++) {
out.writeObject(Array.get(object, ii));
}
}
@Override
public Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException
{
int length = in.readInt();
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Creating array '" +
_componentType.getName() + "[" + length + "]'.");
}
return Array.newInstance(_componentType, length);
}
@Override
public void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException
{
int length = Array.getLength(object);
for (int ii = 0; ii < length; ii++) {
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Reading free element '" + ii + "'.");
}
Array.set(object, ii, in.readObject());
}
}
@Override
protected Objects.ToStringHelper toStringHelper ()
{
return super.toStringHelper()
.add("componentType", _componentType.getName());
}
/** The class of our component type. */
protected Class _componentType;
} // end: static class ArrayStreamer
/**
* A streamer for arrays with a final component type.
*/
protected static class FinalArrayStreamer extends ArrayStreamer
{
/** Constructor. */
protected FinalArrayStreamer (Class componentType, Streamer delegate)
{
super(componentType);
_delegate = delegate;
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
int length = Array.getLength(object);
out.writeInt(length);
// The component class is final, we can be sure that all instances in the array will
// be of the same class and thus can serialize things more efficiently.
// Compute a mask indicating which elements are null and which are populated
ArrayMask mask = new ArrayMask(length);
for (int ii = 0; ii < length; ii++) {
if (Array.get(object, ii) != null) {
mask.set(ii);
}
}
// write that mask out to the stream
mask.writeTo(out);
// now write out the populated elements
for (int ii = 0; ii < length; ii++) {
Object element = Array.get(object, ii);
if (element != null) {
out.writeBareObject(element, _delegate, useWriter);
}
}
}
@Override
public void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException
{
int length = Array.getLength(object);
// The component class is final, we can be sure that all instances in the array will
// be of the same class and thus have serialized things more efficiently
// Read in the nullness mask.
ArrayMask mask = new ArrayMask();
mask.readFrom(in);
// now read in the array elements given that we know which elements to read
for (int ii = 0; ii < length; ii++) {
if (mask.isSet(ii)) {
if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Reading fixed element '" + ii + "'.");
}
Object element = _delegate.createObject(in);
in.readBareObject(element, _delegate, useReader);
Array.set(object, ii, element);
} else if (ObjectInputStream.STREAM_DEBUG) {
log.info(in.hashCode() + ": Skipping null element '" + ii + "'.");
}
}
}
@Override
protected Objects.ToStringHelper toStringHelper ()
{
return super.toStringHelper()
.add("delegate", _delegate);
}
/** Our delegate streamer. */
protected Streamer _delegate;
} // end: static class FinalArrayStreamer
/**
* Base class for Enum streamers.
*/
protected static abstract class EnumStreamer extends Streamer
{
/** Constructor. */
protected EnumStreamer (Class target)
{
@SuppressWarnings("unchecked")
Class eclass = (Class)target;
_eclass = eclass;
}
@Override
public void readObject (Object object, ObjectInputStream in, boolean useReader)
throws IOException, ClassNotFoundException
{
// nothing here: handled in createObject
}
@Override
public Objects.ToStringHelper toStringHelper ()
{
return super.toStringHelper()
.add("eclass", _eclass.getName());
}
/** Used to coerce the type system into quietude when reading enums from the wire. */
protected static enum EnumReader implements ByteEnum {
NOT_USED;
public byte toByte () { return 0; }
}
/** Our enum class, not actually an EnumReader. */
protected Class _eclass;
} // end: static abstract class EnumStreamer
/**
* Streams ByteEnums, if that's what's desired.
*/
protected static class ByteEnumStreamer extends EnumStreamer
{
/** Constructor. */
protected ByteEnumStreamer (Class target)
{
super(target);
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
out.writeByte(((ByteEnum) object).toByte());
}
@Override
public Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException
{
return ByteEnumUtil.fromByte(_eclass, in.readByte());
}
} // end: static class ByteEnumStreamer
/**
* Streams enums by name.
*/
protected static class NameEnumStreamer extends EnumStreamer
{
/** Constructor. */
protected NameEnumStreamer (Class target)
{
super(target);
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
out.writeUTF(((Enum)object).name());
}
@Override
public Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException
{
return Enum.valueOf(_eclass, in.readUTF());
}
} // end: static class NameEnumStreamer
/**
* Base class for enum streamers that stream by ordinal.
*/
protected static abstract class OrdEnumStreamer extends EnumStreamer
{
/** Constructor. */
protected OrdEnumStreamer (Class target, List universe)
{
super(target);
_universe = universe;
}
@Override
public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
throws IOException
{
int code = (object == null) ? -1 : ((Enum)object).ordinal();
writeCode(out, code);
}
@Override
public Object createObject (ObjectInputStream in)
throws IOException, ClassNotFoundException
{
int code = readCode(in);
return (code == -1) ? null : _universe.get(code);
}
/** Write the ordinal code. */
protected abstract void writeCode (ObjectOutputStream out, int code)
throws IOException;
/** Read the ordinal code. */
protected abstract int readCode (ObjectInputStream in)
throws IOException;
/** The universe of this enum. */
protected List _universe;
} // end: static abstract class OrdEnumStreamer
/**
* Streams enums by the byte value of their ordinal.
*/
protected static class ByteOrdEnumStreamer extends OrdEnumStreamer
{
/** Constructor. */
protected ByteOrdEnumStreamer (Class target, List universe)
{
super(target, universe);
}
@Override
protected void writeCode (ObjectOutputStream out, int code)
throws IOException
{
out.writeByte((byte)code);
}
@Override
protected int readCode (ObjectInputStream in)
throws IOException
{
return in.readByte();
}
} // end: static class ByteOrdEnumStreamer
/**
* Streams enums by the short value of their ordinal.
*/
protected static class ShortOrdEnumStreamer extends OrdEnumStreamer
{
/** Constructor. */
protected ShortOrdEnumStreamer (Class target, List universe)
{
super(target, universe);
}
@Override
protected void writeCode (ObjectOutputStream out, int code)
throws IOException
{
out.writeShort((short)code);
}
@Override
protected int readCode (ObjectInputStream in)
throws IOException
{
return in.readShort();
}
} // end: static class ShortOrdEnumStreamer
/**
* Streams enums by the int value of their ordinal.
*/
protected static class IntOrdEnumStreamer extends OrdEnumStreamer
{
/** Constructor. */
protected IntOrdEnumStreamer (Class target, List universe)
{
super(target, universe);
}
@Override
protected void writeCode (ObjectOutputStream out, int code)
throws IOException
{
out.writeInt(code);
}
@Override
protected int readCode (ObjectInputStream in)
throws IOException
{
return in.readInt();
}
} // end: static class IntOrdEnumStreamer
/**
* Initializes static state if necessary.
*/
protected synchronized static void maybeInit ()
{
if (_streamers == null) {
_streamers = Maps.newHashMap(BasicStreamers.BSTREAMERS);
}
}
/** Contains the mapping from class names to configured streamer instances. */
protected static Map, Streamer> _streamers;
/** Should we sort fields in streamable classes? */
protected static final boolean SORT_FIELDS =
Boolean.getBoolean("com.threerings.io.streamFieldsAlphabetically");
/** Our policy on handling enum classes. */
protected static final EnumPolicy ENUM_POLICY = EnumPolicy.create();
/** Compares fields by name. */
protected static final Comparator FIELD_NAME_ORDER = new Comparator() {
public int compare (Field arg0, Field arg1)
{
return arg0.getName().compareTo(arg1.getName());
}
};
/**
* The enum policy of this streamer, determined at start time by examining
* a system property.
*/
protected enum EnumPolicy
{
NAME, NAME_WITH_BYTE_ENUM, ORDINAL, ORDINAL_WITH_BYTE_ENUM;
/**
* Create the static enum policy by checking the com.threerings.io.enumPolicy system prop.
*/
public static EnumPolicy create ()
{
String policy = System.getProperty("com.threerings.io.enumPolicy");
try {
return valueOf(policy);
} catch (Exception e) {
return NAME_WITH_BYTE_ENUM;
}
}
}
/** The name of the custom reader method. */
protected static final String READER_METHOD_NAME = "readObject";
/** The argument list for the custom reader method. */
protected static final Class[] READER_ARGS = { ObjectInputStream.class };
/** The name of the custom writer method. */
protected static final String WRITER_METHOD_NAME = "writeObject";
/** The argument list for the custom writer method. */
protected static final Class[] WRITER_ARGS = { ObjectOutputStream.class };
/** Filters "NotStreamable" members from a field list. */
protected static final Predicate IS_STREAMABLE = new Predicate() {
public boolean apply (Field obj) {
return (obj.getAnnotation(NotStreamable.class) == null);
}
};
/** Filters "NotStreamable" members and enclosing class refs from a field list. */
protected static final Predicate IS_STREAMCLOSURE = new Predicate() {
public boolean apply (Field obj) {
return IS_STREAMABLE.apply(obj) &&
!(obj.isSynthetic() && obj.getName().startsWith("this$"));
}
};
}
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