java.io.ObjectOutputStream Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jtransc-rt Show documentation
Show all versions of jtransc-rt Show documentation
JVM AOT compiler currently generating JavaScript, C++, Haxe, with initial focus on Kotlin and games.
The newest version!
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.io;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import com.jtransc.charset.ModifiedUtf8;
import libcore.io.Memory;
import java.nio.internal.SizeOf;
import java.util.List;
/**
* A specialized {@link OutputStream} that is able to write (serialize) Java
* objects as well as primitive data types (int, byte, char etc.). The data can
* later be loaded using an ObjectInputStream.
*
* @see ObjectInputStream
* @see ObjectOutput
* @see Serializable
* @see Externalizable
*/
public class ObjectOutputStream extends OutputStream implements ObjectOutput, ObjectStreamConstants {
private static final Class[] WRITE_UNSHARED_PARAM_TYPES = new Class[] { Object.class };
/*
* Mask to zero SC_BLOC_DATA bit.
*/
private static final byte NOT_SC_BLOCK_DATA = (byte) (SC_BLOCK_DATA ^ 0xFF);
/*
* How many nested levels to writeObject. We may not need this.
*/
private int nestedLevels;
/*
* Where we write to
*/
private DataOutputStream output;
/*
* If object replacement is enabled or not
*/
private boolean enableReplace;
/*
* Where we write primitive types to
*/
private DataOutputStream primitiveTypes;
/*
* Where the write primitive types are actually written to
*/
private ByteArrayOutputStream primitiveTypesBuffer;
/*
* Table mapping Object -> Integer (handle)
*/
private SerializationHandleMap objectsWritten;
/*
* All objects are assigned an ID (integer handle)
*/
private int currentHandle;
/*
* Used by defaultWriteObject
*/
private Object currentObject;
/*
* Used by defaultWriteObject
*/
private ObjectStreamClass currentClass;
/*
* Either ObjectStreamConstants.PROTOCOL_VERSION_1 or
* ObjectStreamConstants.PROTOCOL_VERSION_2
*/
private int protocolVersion;
/*
* Used to detect nested exception when saving an exception due to an error
*/
private StreamCorruptedException nestedException;
/*
* Used to keep track of the PutField object for the class/object being
* written
*/
private EmulatedFieldsForDumping currentPutField;
/*
* Allows the receiver to decide if it needs to call writeObjectOverride
*/
private boolean subclassOverridingImplementation;
/*
* Descriptor for java.lang.reflect.Proxy
*/
private final ObjectStreamClass proxyClassDesc = ObjectStreamClass.lookup(Proxy.class);
/**
* PutField is an inner class to provide access to the persistent fields
* that are written to the target stream.
*/
public static abstract class PutField {
/**
* Puts the value of the boolean field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, boolean value);
/**
* Puts the value of the character field identified by {@code name} to
* the persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, char value);
/**
* Puts the value of the byte field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, byte value);
/**
* Puts the value of the short field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, short value);
/**
* Puts the value of the integer field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, int value);
/**
* Puts the value of the long field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, long value);
/**
* Puts the value of the float field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, float value);
/**
* Puts the value of the double field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, double value);
/**
* Puts the value of the Object field identified by {@code name} to the
* persistent field.
*
* @param name
* the name of the field to serialize.
* @param value
* the value that is put to the persistent field.
*/
public abstract void put(String name, Object value);
/**
* Writes the fields to the target stream {@code out}.
*
* @param out
* the target stream
* @throws IOException
* if an error occurs while writing to the target stream.
* @deprecated This method is unsafe and may corrupt the target stream.
* Use ObjectOutputStream#writeFields() instead.
*/
@Deprecated
public abstract void write(ObjectOutput out) throws IOException;
}
/**
* Constructs a new {@code ObjectOutputStream}. This default constructor can
* be used by subclasses that do not want to use the public constructor if
* it allocates unneeded data.
*
* @throws IOException
* if an error occurs when creating this stream.
*/
protected ObjectOutputStream() throws IOException {
/*
* WARNING - we should throw IOException if not called from a subclass
* according to the JavaDoc. Add the test.
*/
this.subclassOverridingImplementation = true;
}
/**
* Constructs a new ObjectOutputStream that writes to the OutputStream
* {@code output}.
*
* @param output
* the non-null OutputStream to filter writes on.
*
* @throws IOException
* if an error occurs while writing the object stream
* header
*/
public ObjectOutputStream(OutputStream output) throws IOException {
this.output = (output instanceof DataOutputStream) ? (DataOutputStream) output
: new DataOutputStream(output);
this.enableReplace = false;
this.protocolVersion = PROTOCOL_VERSION_2;
this.subclassOverridingImplementation = false;
resetState();
this.nestedException = new StreamCorruptedException();
// So write...() methods can be used by
// subclasses during writeStreamHeader()
primitiveTypes = this.output;
// Has to be done here according to the specification
writeStreamHeader();
primitiveTypes = null;
}
/**
* Writes optional information for class {@code aClass} to the output
* stream. This optional data can be read when deserializing the class
* descriptor (ObjectStreamClass) for this class from an input stream. By
* default, no extra data is saved.
*
* @param aClass
* the class to annotate.
* @throws IOException
* if an error occurs while writing to the target stream.
* @see ObjectInputStream#resolveClass(ObjectStreamClass)
*/
protected void annotateClass(Class aClass) throws IOException {
// By default no extra info is saved. Subclasses can override
}
/**
* Writes optional information for a proxy class to the target stream. This
* optional data can be read when deserializing the proxy class from an
* input stream. By default, no extra data is saved.
*
* @param aClass
* the proxy class to annotate.
* @throws IOException
* if an error occurs while writing to the target stream.
* @see ObjectInputStream#resolveProxyClass(String[])
*/
protected void annotateProxyClass(Class aClass) throws IOException {
// By default no extra info is saved. Subclasses can override
}
/**
* Do the necessary work to see if the receiver can be used to write
* primitive types like int, char, etc.
*/
private void checkWritePrimitiveTypes() {
if (primitiveTypes == null) {
// If we got here we have no Stream previously created
// WARNING - if the stream does not grow, this code is wrong
primitiveTypesBuffer = new ByteArrayOutputStream(128);
primitiveTypes = new DataOutputStream(primitiveTypesBuffer);
}
}
/**
* Closes this stream. Any buffered data is flushed. This implementation
* closes the target stream.
*
* @throws IOException
* if an error occurs while closing this stream.
*/
@Override
public void close() throws IOException {
// First flush what is needed (primitive data, etc)
flush();
output.close();
}
/**
* Computes the collection of emulated fields that users can manipulate to
* store a representation different than the one declared by the class of
* the object being dumped.
*
* @see #writeFields
* @see #writeFieldValues(EmulatedFieldsForDumping)
*/
private void computePutField() {
currentPutField = new EmulatedFieldsForDumping(this, currentClass);
}
/**
* Default method to write objects to this stream. Serializable fields
* defined in the object's class and superclasses are written to the output
* stream.
*
* @throws IOException
* if an error occurs while writing to the target stream.
* @throws NotActiveException
* if this method is not called from {@code writeObject()}.
* @see ObjectInputStream#defaultReadObject
*/
public void defaultWriteObject() throws IOException {
if (currentObject == null) {
throw new NotActiveException();
}
writeFieldValues(currentObject, currentClass);
}
/**
* Writes buffered data to the target stream. This is similar to {@code
* flush} but the flush is not propagated to the target stream.
*
* @throws IOException
* if an error occurs while writing to the target stream.
*/
protected void drain() throws IOException {
if (primitiveTypes == null || primitiveTypesBuffer == null) {
return;
}
// If we got here we have a Stream previously created
int offset = 0;
byte[] written = primitiveTypesBuffer.toByteArray();
// Normalize the primitive data
while (offset < written.length) {
int toWrite = written.length - offset > 1024 ? 1024
: written.length - offset;
if (toWrite < 256) {
output.writeByte(TC_BLOCKDATA);
output.writeByte((byte) toWrite);
} else {
output.writeByte(TC_BLOCKDATALONG);
output.writeInt(toWrite);
}
// write primitive types we had and the marker of end-of-buffer
output.write(written, offset, toWrite);
offset += toWrite;
}
// and now we're clean to a state where we can write an object
primitiveTypes = null;
primitiveTypesBuffer = null;
}
/**
* Dumps the parameter {@code obj} only if it is {@code null}
* or an object that has already been dumped previously.
*
* @param obj
* Object to check if an instance previously dumped by this
* stream.
* @return -1 if it is an instance which has not been dumped yet (and this
* method does nothing). The handle if {@code obj} is an
* instance which has been dumped already.
*
* @throws IOException
* If an error occurs attempting to save {@code null} or
* a cyclic reference.
*/
private int dumpCycle(Object obj) throws IOException {
// If the object has been saved already, save its handle only
int handle = objectsWritten.get(obj);
if (handle != -1) {
writeCyclicReference(handle);
return handle;
}
return -1;
}
/**
* Enables object replacement for this stream. By default this is not
* enabled. Only trusted subclasses (loaded with system class loader) are
* allowed to change this status.
*
* @param enable
* {@code true} to enable object replacement; {@code false} to
* disable it.
* @return the previous setting.
* @see #replaceObject
* @see ObjectInputStream#enableResolveObject
*/
protected boolean enableReplaceObject(boolean enable) {
boolean originalValue = enableReplace;
enableReplace = enable;
return originalValue;
}
/**
* Writes buffered data to the target stream and calls the {@code flush}
* method of the target stream.
*
* @throws IOException
* if an error occurs while writing to or flushing the output
* stream.
*/
@Override
public void flush() throws IOException {
drain();
output.flush();
}
/*
* These methods get the value of a field named fieldName of object
* instance. The field is declared by declaringClass. The field is the same
* type as the method return value.
*
* these methods could be implemented non-natively on top of
* java.lang.reflect at the expense of extra object creation
* (java.lang.reflect.Field). Otherwise Serialization could not fetch
* private fields, except by the use of a native method like this one.
*
* @throws NoSuchFieldError If the field does not exist.
*/
private static native Object getFieldL(Object instance, Class declaringClass, String fieldName, String fieldTypeName);
/**
* Return the next handle to be used to indicate cyclic
* references being saved to the stream.
*
* @return the next handle to represent the next cyclic reference
*/
private int nextHandle() {
return currentHandle++;
}
/**
* Gets this stream's {@code PutField} object. This object provides access
* to the persistent fields that are eventually written to the output
* stream. It is used to transfer the values from the fields of the object
* that is currently being written to the persistent fields.
*
* @return the PutField object from which persistent fields can be accessed
* by name.
* @throws IOException
* if an I/O error occurs.
* @throws NotActiveException
* if this method is not called from {@code writeObject()}.
* @see ObjectInputStream#defaultReadObject
*/
public PutField putFields() throws IOException {
if (currentObject == null) {
throw new NotActiveException();
}
if (currentPutField == null) {
computePutField();
}
return currentPutField;
}
private int registerObjectWritten(Object obj) {
int handle = nextHandle();
objectsWritten.put(obj, handle);
return handle;
}
/**
* Remove the unshared object from the table, and restore any previous
* handle.
*
* @param obj
* Non-null object being dumped.
* @param previousHandle
* The handle of the previous identical object dumped
*/
private void removeUnsharedReference(Object obj, int previousHandle) {
if (previousHandle != -1) {
objectsWritten.put(obj, previousHandle);
} else {
objectsWritten.remove(obj);
}
}
/**
* Allows trusted subclasses to substitute the specified original {@code
* object} with a new object. Object substitution has to be activated first
* with calling {@code enableReplaceObject(true)}. This implementation just
* returns {@code object}.
*
* @param object
* the original object for which a replacement may be defined.
* @return the replacement object for {@code object}.
* @throws IOException
* if any I/O error occurs while creating the replacement
* object.
* @see #enableReplaceObject
* @see ObjectInputStream#enableResolveObject
* @see ObjectInputStream#resolveObject
*/
protected Object replaceObject(Object object) throws IOException {
// By default no object replacement. Subclasses can override
return object;
}
/**
* Resets the state of this stream. A marker is written to the stream, so
* that the corresponding input stream will also perform a reset at the same
* point. Objects previously written are no longer remembered, so they will
* be written again (instead of a cyclical reference) if found in the object
* graph.
*
* @throws IOException
* if {@code reset()} is called during the serialization of an
* object.
*/
public void reset() throws IOException {
// First we flush what we have
drain();
/*
* And dump a reset marker, so that the ObjectInputStream can reset
* itself at the same point
*/
output.writeByte(TC_RESET);
// Now we reset ourselves
resetState();
}
/**
* Reset the collection of objects already dumped by the receiver. If the
* objects are found again in the object graph, the receiver will dump them
* again, instead of a handle (cyclic reference).
*
*/
private void resetSeenObjects() {
objectsWritten = new SerializationHandleMap();
currentHandle = baseWireHandle;
}
/**
* Reset the receiver. The collection of objects already dumped by the
* receiver is reset, and internal structures are also reset so that the
* receiver knows it is in a fresh clean state.
*
*/
private void resetState() {
resetSeenObjects();
nestedLevels = 0;
}
/**
* Sets the specified protocol version to be used by this stream.
*
* @param version
* the protocol version to be used. Use a {@code
* PROTOCOL_VERSION_x} constant from {@code
* java.io.ObjectStreamConstants}.
* @throws IllegalArgumentException
* if an invalid {@code version} is specified.
* @throws IOException
* if an I/O error occurs.
* @see ObjectStreamConstants#PROTOCOL_VERSION_1
* @see ObjectStreamConstants#PROTOCOL_VERSION_2
*/
public void useProtocolVersion(int version) throws IOException {
if (!objectsWritten.isEmpty()) {
throw new IllegalStateException("Cannot set protocol version when stream in use");
}
if (version != ObjectStreamConstants.PROTOCOL_VERSION_1
&& version != ObjectStreamConstants.PROTOCOL_VERSION_2) {
throw new IllegalArgumentException("Unknown protocol: " + version);
}
protocolVersion = version;
}
/**
* Writes {@code count} bytes from the byte array {@code buffer} starting at
* offset {@code index} to the target stream. Blocks until all bytes are
* written.
*
* @param buffer
* the buffer to write.
* @param offset
* the index of the first byte in {@code buffer} to write.
* @param length
* the number of bytes from {@code buffer} to write to the output
* stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
@Override
public void write(byte[] buffer, int offset, int length) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.write(buffer, offset, length);
}
public void write(byte[] buf) throws IOException {
write(buf, 0, buf.length);
}
/**
* Writes a single byte to the target stream. Only the least significant
* byte of the integer {@code value} is written to the stream. Blocks until
* the byte is actually written.
*
* @param value
* the byte to write.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
@Override
public void write(int value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.write(value);
}
/**
* Writes a boolean to the target stream.
*
* @param value
* the boolean value to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeBoolean(boolean value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeBoolean(value);
}
/**
* Writes a byte (8 bit) to the target stream.
*
* @param value
* the byte to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeByte(int value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeByte(value);
}
/**
* Writes the string {@code value} as a sequence of bytes to the target
* stream. Only the least significant byte of each character in the string
* is written.
*
* @param value
* the string to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeBytes(String value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeBytes(value);
}
/**
* Writes a character (16 bit) to the target stream.
*
* @param value
* the character to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeChar(int value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeChar(value);
}
/**
* Writes the string {@code value} as a sequence of characters to the target
* stream.
*
* @param value
* the string to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeChars(String value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeChars(value);
}
/**
* Write a class descriptor {@code classDesc} (an
* {@code ObjectStreamClass}) to the stream.
*
* @param classDesc
* The class descriptor (an {@code ObjectStreamClass}) to
* be dumped
* @param unshared
* Write the object unshared
* @return the handle assigned to the class descriptor
*
* @throws IOException
* If an IO exception happened when writing the class
* descriptor.
*/
private int writeClassDesc(ObjectStreamClass classDesc, boolean unshared) throws IOException {
if (classDesc == null) {
writeNull();
return -1;
}
int handle = -1;
if (!unshared) {
handle = dumpCycle(classDesc);
}
if (handle == -1) {
Class classToWrite = classDesc.forClass();
int previousHandle = -1;
if (unshared) {
previousHandle = objectsWritten.get(classDesc);
}
// If we got here, it is a new (non-null) classDesc that will have
// to be registered as well
handle = registerObjectWritten(classDesc);
if (classDesc.isProxy()) {
output.writeByte(TC_PROXYCLASSDESC);
Class[] interfaces = classToWrite.getInterfaces();
output.writeInt(interfaces.length);
for (int i = 0; i < interfaces.length; i++) {
output.writeUTF(interfaces[i].getName());
}
annotateProxyClass(classToWrite);
output.writeByte(TC_ENDBLOCKDATA);
writeClassDesc(proxyClassDesc, false);
if (unshared) {
// remove reference to unshared object
removeUnsharedReference(classDesc, previousHandle);
}
return handle;
}
output.writeByte(TC_CLASSDESC);
if (protocolVersion == PROTOCOL_VERSION_1) {
writeNewClassDesc(classDesc);
} else {
// So write...() methods can be used by
// subclasses during writeClassDescriptor()
primitiveTypes = output;
writeClassDescriptor(classDesc);
primitiveTypes = null;
}
// Extra class info (optional)
annotateClass(classToWrite);
drain(); // flush primitive types in the annotation
output.writeByte(TC_ENDBLOCKDATA);
writeClassDesc(classDesc.getSuperclass(), unshared);
if (unshared) {
// remove reference to unshared object
removeUnsharedReference(classDesc, previousHandle);
}
}
return handle;
}
/**
* Writes a handle representing a cyclic reference (object previously
* dumped).
*/
private void writeCyclicReference(int handle) throws IOException {
output.writeByte(TC_REFERENCE);
output.writeInt(handle);
}
/**
* Writes a double (64 bit) to the target stream.
*
* @param value
* the double to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeDouble(double value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeDouble(value);
}
/**
* Writes a collection of field descriptors (name, type name, etc) for the
* class descriptor {@code classDesc} (an
* {@code ObjectStreamClass})
*
* @param classDesc
* The class descriptor (an {@code ObjectStreamClass})
* for which to write field information
* @param externalizable
* true if the descriptors are externalizable
*
* @throws IOException
* If an IO exception happened when writing the field
* descriptors.
*
* @see #writeObject(Object)
*/
private void writeFieldDescriptors(ObjectStreamClass classDesc, boolean externalizable) throws IOException {
Class loadedClass = classDesc.forClass();
ObjectStreamField[] fields = null;
int fieldCount = 0;
// The fields of String are not needed since Strings are treated as
// primitive types
if (!externalizable && loadedClass != ObjectStreamClass.STRINGCLASS) {
fields = classDesc.fields();
fieldCount = fields.length;
}
// Field count
output.writeShort(fieldCount);
// Field names
for (int i = 0; i < fieldCount; i++) {
ObjectStreamField f = fields[i];
boolean wasPrimitive = f.writeField(output);
if (!wasPrimitive) {
writeObject(f.getTypeString());
}
}
}
/**
* Writes the fields of the object currently being written to the target
* stream. The field values are buffered in the currently active {@code
* PutField} object, which can be accessed by calling {@code putFields()}.
*
* @throws IOException
* if an error occurs while writing to the target stream.
* @throws NotActiveException
* if there are no fields to write to the target stream.
* @see #putFields
*/
public void writeFields() throws IOException {
// Has to have fields to write
if (currentPutField == null) {
throw new NotActiveException();
}
writeFieldValues(currentPutField);
}
/**
* Writes a collection of field values for the emulated fields
* {@code emulatedFields}
*
* @param emulatedFields
* an {@code EmulatedFieldsForDumping}, concrete subclass
* of {@code PutField}
*
* @throws IOException
* If an IO exception happened when writing the field values.
*
* @see #writeFields
* @see #writeObject(Object)
*/
private void writeFieldValues(EmulatedFieldsForDumping emulatedFields) throws IOException {
// Access internal fields which we can set/get. Users can't do this.
EmulatedFields accessibleSimulatedFields = emulatedFields.emulatedFields();
for (EmulatedFields.ObjectSlot slot : accessibleSimulatedFields.slots()) {
Object fieldValue = slot.getFieldValue();
Class type = slot.getField().getType();
if (type == int.class) {
output.writeInt(fieldValue != null ? ((Integer) fieldValue).intValue() : 0);
} else if (type == byte.class) {
output.writeByte(fieldValue != null ? ((Byte) fieldValue).byteValue() : 0);
} else if (type == char.class) {
output.writeChar(fieldValue != null ? ((Character) fieldValue).charValue() : 0);
} else if (type == short.class) {
output.writeShort(fieldValue != null ? ((Short) fieldValue).shortValue() : 0);
} else if (type == boolean.class) {
output.writeBoolean(fieldValue != null ? ((Boolean) fieldValue).booleanValue() : false);
} else if (type == long.class) {
output.writeLong(fieldValue != null ? ((Long) fieldValue).longValue() : 0);
} else if (type == float.class) {
output.writeFloat(fieldValue != null ? ((Float) fieldValue).floatValue() : 0);
} else if (type == double.class) {
output.writeDouble(fieldValue != null ? ((Double) fieldValue).doubleValue() : 0);
} else {
// Either array or Object
writeObject(fieldValue);
}
}
}
/**
* Writes a collection of field values for the fields described by class
* descriptor {@code classDesc} (an {@code ObjectStreamClass}).
* This is the default mechanism, when emulated fields (an
* {@code PutField}) are not used. Actual values to dump are fetched
* directly from object {@code obj}.
*
* @param obj
* Instance from which to fetch field values to dump.
* @param classDesc
* A class descriptor (an {@code ObjectStreamClass})
* defining which fields should be dumped.
*
* @throws IOException
* If an IO exception happened when writing the field values.
*
* @see #writeObject(Object)
*/
private void writeFieldValues(Object obj, ObjectStreamClass classDesc) throws IOException {
for (ObjectStreamField fieldDesc : classDesc.fields()) {
try {
Class type = fieldDesc.getTypeInternal();
Field field = classDesc.getReflectionField(fieldDesc);
if (field == null) {
throw new InvalidClassException(classDesc.getName() + " doesn't have a field " + fieldDesc.getName() + " of type " + type);
}
if (type == byte.class) {
output.writeByte(field.getByte(obj));
} else if (type == char.class) {
output.writeChar(field.getChar(obj));
} else if (type == double.class) {
output.writeDouble(field.getDouble(obj));
} else if (type == float.class) {
output.writeFloat(field.getFloat(obj));
} else if (type == int.class) {
output.writeInt(field.getInt(obj));
} else if (type == long.class) {
output.writeLong(field.getLong(obj));
} else if (type == short.class) {
output.writeShort(field.getShort(obj));
} else if (type == boolean.class) {
output.writeBoolean(field.getBoolean(obj));
} else {
// Reference types (including arrays).
Object objField = field.get(obj);
if (fieldDesc.isUnshared()) {
writeUnshared(objField);
} else {
writeObject(objField);
}
}
} catch (IllegalAccessException iae) {
// ObjectStreamField should have called setAccessible(true).
throw new AssertionError(iae);
} catch (NoSuchFieldError nsf) {
// The user defined serialPersistentFields but did not provide
// the glue to transfer values in writeObject, so we ended up using
// the default mechanism but failed to set the emulated field.
throw new InvalidClassException(classDesc.getName());
}
}
}
/**
* Writes a float (32 bit) to the target stream.
*
* @param value
* the float to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeFloat(float value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeFloat(value);
}
/**
* Walks the hierarchy of classes described by class descriptor
* {@code classDesc} and writes the field values corresponding to
* fields declared by the corresponding class descriptor. The instance to
* fetch field values from is {@code object}. If the class
* (corresponding to class descriptor {@code classDesc}) defines
* private instance method {@code writeObject} it will be used to
* dump field values.
*
* @param object
* Instance from which to fetch field values to dump.
* @param classDesc
* A class descriptor (an {@code ObjectStreamClass})
* defining which fields should be dumped.
*
* @throws IOException
* If an IO exception happened when writing the field values in
* the hierarchy.
* @throws NotActiveException
* If the given object is not active
*
* @see #defaultWriteObject
* @see #writeObject(Object)
*/
private void writeHierarchy(Object object, ObjectStreamClass classDesc)
throws IOException, NotActiveException {
if (object == null) {
throw new NotActiveException();
}
// Fields are written from class closest to Object to leaf class
// (down the chain)
List hierarchy = classDesc.getHierarchy();
for (int i = 0, end = hierarchy.size(); i < end; ++i) {
ObjectStreamClass osc = hierarchy.get(i);
// Have to do this before calling defaultWriteObject or anything
// that calls defaultWriteObject
currentObject = object;
currentClass = osc;
// See if the object has a writeObject method. If so, run it
try {
boolean executed = false;
if (osc.hasMethodWriteObject()) {
final Method method = osc.getMethodWriteObject();
try {
method.invoke(object, new Object[] { this });
executed = true;
} catch (InvocationTargetException e) {
Throwable ex = e.getTargetException();
if (ex instanceof RuntimeException) {
throw (RuntimeException) ex;
} else if (ex instanceof Error) {
throw (Error) ex;
}
throw (IOException) ex;
} catch (IllegalAccessException e) {
throw new RuntimeException(e.toString());
}
}
if (executed) {
drain();
output.writeByte(TC_ENDBLOCKDATA);
} else {
// If the object did not have a writeMethod, call
// defaultWriteObject
defaultWriteObject();
}
} finally {
// Cleanup, needs to run always so that we can later detect
// invalid calls to defaultWriteObject
currentObject = null;
currentClass = null;
currentPutField = null;
}
}
}
/**
* Writes an integer (32 bit) to the target stream.
*
* @param value
* the integer to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeInt(int value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeInt(value);
}
/**
* Writes a long (64 bit) to the target stream.
*
* @param value
* the long to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeLong(long value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeLong(value);
}
/**
* Write array {@code array} of class {@code arrayClass} with
* component type {@code componentType} into the receiver. It is
* assumed the array has not been dumped yet. Returns
* the handle for this object (array) which is dumped here.
*
* @param array
* The array object to dump
* @param arrayClass
* A {@code java.lang.Class} representing the class of the
* array
* @param componentType
* A {@code java.lang.Class} representing the array
* component type
* @return the handle assigned to the array
*
* @throws IOException
* If an IO exception happened when writing the array.
*/
private int writeNewArray(Object array, Class arrayClass, ObjectStreamClass arrayClDesc,
Class componentType, boolean unshared) throws IOException {
output.writeByte(TC_ARRAY);
writeClassDesc(arrayClDesc, false);
int handle = nextHandle();
if (!unshared) {
objectsWritten.put(array, handle);
}
// Now we have code duplication just because Java is typed. We have to
// write N elements and assign to array positions, but we must typecast
// the array first, and also call different methods depending on the
// elements.
if (componentType.isPrimitive()) {
if (componentType == int.class) {
int[] intArray = (int[]) array;
output.writeInt(intArray.length);
for (int i = 0; i < intArray.length; i++) {
output.writeInt(intArray[i]);
}
} else if (componentType == byte.class) {
byte[] byteArray = (byte[]) array;
output.writeInt(byteArray.length);
output.write(byteArray, 0, byteArray.length);
} else if (componentType == char.class) {
char[] charArray = (char[]) array;
output.writeInt(charArray.length);
for (int i = 0; i < charArray.length; i++) {
output.writeChar(charArray[i]);
}
} else if (componentType == short.class) {
short[] shortArray = (short[]) array;
output.writeInt(shortArray.length);
for (int i = 0; i < shortArray.length; i++) {
output.writeShort(shortArray[i]);
}
} else if (componentType == boolean.class) {
boolean[] booleanArray = (boolean[]) array;
output.writeInt(booleanArray.length);
for (int i = 0; i < booleanArray.length; i++) {
output.writeBoolean(booleanArray[i]);
}
} else if (componentType == long.class) {
long[] longArray = (long[]) array;
output.writeInt(longArray.length);
for (int i = 0; i < longArray.length; i++) {
output.writeLong(longArray[i]);
}
} else if (componentType == float.class) {
float[] floatArray = (float[]) array;
output.writeInt(floatArray.length);
for (int i = 0; i < floatArray.length; i++) {
output.writeFloat(floatArray[i]);
}
} else if (componentType == double.class) {
double[] doubleArray = (double[]) array;
output.writeInt(doubleArray.length);
for (int i = 0; i < doubleArray.length; i++) {
output.writeDouble(doubleArray[i]);
}
} else {
throw new InvalidClassException("Wrong base type in " + arrayClass.getName());
}
} else {
// Array of Objects
Object[] objectArray = (Object[]) array;
output.writeInt(objectArray.length);
for (int i = 0; i < objectArray.length; i++) {
// TODO: This place is the opportunity for enhancement
// We can implement writing elements through fast-path,
// without setting up the context (see writeObject()) for
// each element with public API
writeObject(objectArray[i]);
}
}
return handle;
}
/**
* Write class {@code object} into the receiver. It is assumed the
* class has not been dumped yet. Classes are not really dumped, but a class
* descriptor ({@code ObjectStreamClass}) that corresponds to them.
* Returns the handle for this object (class) which is dumped here.
*
* @param object
* The {@code java.lang.Class} object to dump
* @return the handle assigned to the class being dumped
*
* @throws IOException
* If an IO exception happened when writing the class.
*/
private int writeNewClass(Class object, boolean unshared) throws IOException {
output.writeByte(TC_CLASS);
// Instances of java.lang.Class are always Serializable, even if their
// instances aren't (e.g. java.lang.Object.class).
// We cannot call lookup because it returns null if the parameter
// represents instances that cannot be serialized, and that is not what
// we want.
ObjectStreamClass clDesc = ObjectStreamClass.lookupStreamClass(object);
// The handle for the classDesc is NOT the handle for the class object
// being dumped. We must allocate a new handle and return it.
if (clDesc.isEnum()) {
writeEnumDesc(object, clDesc, unshared);
} else {
writeClassDesc(clDesc, unshared);
}
int handle = nextHandle();
if (!unshared) {
objectsWritten.put(object, handle);
}
return handle;
}
/**
* Write class descriptor {@code classDesc} into the receiver. It is
* assumed the class descriptor has not been dumped yet. The class
* descriptors for the superclass chain will be dumped as well. Returns
* the handle for this object (class descriptor) which is dumped here.
*
* @param classDesc
* The {@code ObjectStreamClass} object to dump
*
* @throws IOException
* If an IO exception happened when writing the class
* descriptor.
*/
private void writeNewClassDesc(ObjectStreamClass classDesc)
throws IOException {
output.writeUTF(classDesc.getName());
output.writeLong(classDesc.getSerialVersionUID());
byte flags = classDesc.getFlags();
boolean externalizable = classDesc.isExternalizable();
if (externalizable) {
if (protocolVersion == PROTOCOL_VERSION_1) {
flags &= NOT_SC_BLOCK_DATA;
} else {
// Change for 1.2. Objects can be saved in old format
// (PROTOCOL_VERSION_1) or in the 1.2 format (PROTOCOL_VERSION_2).
flags |= SC_BLOCK_DATA;
}
}
output.writeByte(flags);
if ((SC_ENUM | SC_SERIALIZABLE) != classDesc.getFlags()) {
writeFieldDescriptors(classDesc, externalizable);
} else {
// enum write no fields
output.writeShort(0);
}
}
/**
* Writes a class descriptor to the target stream.
*
* @param classDesc
* the class descriptor to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
protected void writeClassDescriptor(ObjectStreamClass classDesc)
throws IOException {
writeNewClassDesc(classDesc);
}
/**
* Write exception {@code ex} into the receiver. It is assumed the
* exception has not been dumped yet. Returns
* the handle for this object (exception) which is dumped here.
* This is used to dump the exception instance that happened (if any) when
* dumping the original object graph. The set of seen objects will be reset
* just before and just after dumping this exception object.
*
* When exceptions are found normally in the object graph, they are dumped
* as a regular object, and not by this method. In that case, the set of
* "known objects" is not reset.
*
* @param ex
* Exception object to dump
*
* @throws IOException
* If an IO exception happened when writing the exception
* object.
*/
private void writeNewException(Exception ex) throws IOException {
output.writeByte(TC_EXCEPTION);
resetSeenObjects();
writeObjectInternal(ex, false, false, false); // No replacements
resetSeenObjects();
}
/**
* Write object {@code object} of class {@code theClass} into
* the receiver. It is assumed the object has not been dumped yet.
* Return the handle for this object which
* is dumped here.
*
* If the object implements {@code Externalizable} its
* {@code writeExternal} is called. Otherwise, all fields described
* by the class hierarchy is dumped. Each class can define how its declared
* instance fields are dumped by defining a private method
* {@code writeObject}
*
* @param object
* The object to dump
* @param theClass
* A {@code java.lang.Class} representing the class of the
* object
* @param unshared
* Write the object unshared
* @return the handle assigned to the object
*
* @throws IOException
* If an IO exception happened when writing the object.
*/
private int writeNewObject(Object object, Class theClass, ObjectStreamClass clDesc,
boolean unshared) throws IOException {
// Not String, not null, not array, not cyclic reference
EmulatedFieldsForDumping originalCurrentPutField = currentPutField; // save
currentPutField = null; // null it, to make sure one will be computed if
// needed
boolean externalizable = clDesc.isExternalizable();
boolean serializable = clDesc.isSerializable();
if (!externalizable && !serializable) {
// Object is neither externalizable nor serializable. Error
throw new NotSerializableException(theClass.getName());
}
// Either serializable or externalizable, now we can save info
output.writeByte(TC_OBJECT);
writeClassDesc(clDesc, false);
int previousHandle = -1;
if (unshared) {
previousHandle = objectsWritten.get(object);
}
int handle = registerObjectWritten(object);
// This is how we know what to do in defaultWriteObject. And it is also
// used by defaultWriteObject to check if it was called from an invalid
// place.
// It allows writeExternal to call defaultWriteObject and have it work.
currentObject = object;
currentClass = clDesc;
try {
if (externalizable) {
boolean noBlockData = protocolVersion == PROTOCOL_VERSION_1;
if (noBlockData) {
primitiveTypes = output;
}
// Object is externalizable, just call its own method
((Externalizable) object).writeExternal(this);
if (noBlockData) {
primitiveTypes = null;
} else {
// Similar to the code in writeHierarchy when object
// implements writeObject.
// Any primitive data has to be flushed and a tag must be
// written
drain();
output.writeByte(TC_ENDBLOCKDATA);
}
} else { // If it got here, it has to be Serializable
// Object is serializable. Walk the class chain writing the
// fields
writeHierarchy(object, currentClass);
}
} finally {
// Cleanup, needs to run always so that we can later detect invalid
// calls to defaultWriteObject
if (unshared) {
// remove reference to unshared object
removeUnsharedReference(object, previousHandle);
}
currentObject = null;
currentClass = null;
currentPutField = originalCurrentPutField;
}
return handle;
}
/**
* Write String {@code object} into the receiver. It is assumed the
* String has not been dumped yet. Returns the handle for this object (String) which is dumped here.
* Strings are saved encoded with {@link DataInput modified UTF-8}.
*
* @param object
* the string to dump.
* @return the handle assigned to the String being dumped
*
* @throws IOException
* If an IO exception happened when writing the String.
*/
private int writeNewString(String object, boolean unshared) throws IOException {
long count = ModifiedUtf8.countBytes(object, false);
byte[] buffer;
int offset = 0;
if (count <= 0xffff) {
buffer = new byte[1 + SizeOf.SHORT + (int) count];
buffer[offset++] = TC_STRING;
Memory.pokeShort(buffer, offset, (short) count, false);
offset += SizeOf.SHORT;
} else {
buffer = new byte[1 + SizeOf.LONG + (int) count];
buffer[offset++] = TC_LONGSTRING;
Memory.pokeLong(buffer, offset, count, false);
offset += SizeOf.LONG;
}
ModifiedUtf8.encode(buffer, offset, object);
output.write(buffer, 0, buffer.length);
int handle = nextHandle();
if (!unshared) {
objectsWritten.put(object, handle);
}
return handle;
}
/**
* Write a special tag that indicates the value {@code null} into the
* receiver.
*
* @throws IOException
* If an IO exception happened when writing the tag for
* {@code null}.
*/
private void writeNull() throws IOException {
output.writeByte(TC_NULL);
}
/**
* Writes an object to the target stream.
*
* @param object
* the object to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
* @see ObjectInputStream#readObject()
*/
public final void writeObject(Object object) throws IOException {
writeObject(object, false);
}
/**
* Writes an unshared object to the target stream. This method is identical
* to {@code writeObject}, except that it always writes a new object to the
* stream versus the use of back-referencing for identical objects by
* {@code writeObject}.
*
* @param object
* the object to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
* @see ObjectInputStream#readUnshared()
*/
public void writeUnshared(Object object) throws IOException {
writeObject(object, true);
}
private void writeObject(Object object, boolean unshared) throws IOException {
boolean setOutput = (primitiveTypes == output);
if (setOutput) {
primitiveTypes = null;
}
// This is the specified behavior in JDK 1.2. Very bizarre way to allow
// behavior overriding.
if (subclassOverridingImplementation && !unshared) {
writeObjectOverride(object);
return;
}
try {
// First we need to flush primitive types if they were written
drain();
// Actual work, and class-based replacement should be computed
// if needed.
writeObjectInternal(object, unshared, true, true);
if (setOutput) {
primitiveTypes = output;
}
} catch (IOException ioEx1) {
// This will make it pass through until the top caller. It also
// lets it pass through the nested exception.
if (nestedLevels == 0 && ioEx1 != nestedException) {
try {
writeNewException(ioEx1);
} catch (IOException ioEx2) {
nestedException.fillInStackTrace();
throw nestedException;
}
}
throw ioEx1; // and then we propagate the original exception
}
}
/**
* Write object {@code object} into the receiver's underlying stream.
*
* @param object
* The object to write
* @param unshared
* Write the object unshared
* @param computeClassBasedReplacement
* A boolean indicating if class-based replacement should be
* computed (if supported) for the object.
* @param computeStreamReplacement
* A boolean indicating if stream-based replacement should be
* computed (if supported) for the object.
* @return the handle assigned to the final object being dumped
*
* @throws IOException
* If an IO exception happened when writing the object
*
* @see ObjectInputStream#readObject()
*/
private int writeObjectInternal(Object object, boolean unshared,
boolean computeClassBasedReplacement,
boolean computeStreamReplacement) throws IOException {
if (object == null) {
writeNull();
return -1;
}
int handle = -1;
if (!unshared) {
handle = dumpCycle(object);
if (handle != -1) {
return handle; // cyclic reference
}
}
// Non-null object, first time seen...
Class objClass = object.getClass();
ObjectStreamClass clDesc = ObjectStreamClass.lookupStreamClass(objClass);
nestedLevels++;
try {
if (!(enableReplace && computeStreamReplacement)) {
// Is it a Class ?
if (objClass == ObjectStreamClass.CLASSCLASS) {
return writeNewClass((Class) object, unshared);
}
// Is it an ObjectStreamClass ?
if (objClass == ObjectStreamClass.OBJECTSTREAMCLASSCLASS) {
return writeClassDesc((ObjectStreamClass) object, unshared);
}
}
if (clDesc.isSerializable() && computeClassBasedReplacement) {
if (clDesc.hasMethodWriteReplace()){
Method methodWriteReplace = clDesc.getMethodWriteReplace();
Object replObj = null;
try {
replObj = methodWriteReplace.invoke(object, (Object[]) null);
} catch (IllegalAccessException iae) {
replObj = object;
} catch (InvocationTargetException ite) {
// WARNING - Not sure this is the right thing to do
// if we can't run the method
Throwable target = ite.getTargetException();
if (target instanceof ObjectStreamException) {
throw (ObjectStreamException) target;
} else if (target instanceof Error) {
throw (Error) target;
} else {
throw (RuntimeException) target;
}
}
if (replObj != object) {
// All over, class-based replacement off this time.
int replacementHandle = writeObjectInternal(replObj, false, false,
computeStreamReplacement);
// Make the original object also map to the same
// handle.
if (replacementHandle != -1) {
objectsWritten.put(object, replacementHandle);
}
return replacementHandle;
}
}
}
// We get here either if class-based replacement was not needed or
// if it was needed but produced the same object or if it could not
// be computed.
if (enableReplace && computeStreamReplacement) {
// Now we compute the stream-defined replacement.
Object streamReplacement = replaceObject(object);
if (streamReplacement != object) {
// All over, class-based replacement off this time.
int replacementHandle = writeObjectInternal(streamReplacement, false,
computeClassBasedReplacement, false);
// Make the original object also map to the same handle.
if (replacementHandle != -1) {
objectsWritten.put(object, replacementHandle);
}
return replacementHandle;
}
}
// We get here if stream-based replacement produced the same object
// Is it a Class ?
if (objClass == ObjectStreamClass.CLASSCLASS) {
return writeNewClass((Class) object, unshared);
}
// Is it an ObjectStreamClass ?
if (objClass == ObjectStreamClass.OBJECTSTREAMCLASSCLASS) {
return writeClassDesc((ObjectStreamClass) object, unshared);
}
// Is it a String ? (instanceof, but == is faster)
if (objClass == ObjectStreamClass.STRINGCLASS) {
return writeNewString((String) object, unshared);
}
// Is it an Array ?
if (objClass.isArray()) {
return writeNewArray(object, objClass, clDesc, objClass
.getComponentType(), unshared);
}
if (object instanceof Enum) {
return writeNewEnum(object, objClass, unshared);
}
// Not a String or Class or Array. Default procedure.
return writeNewObject(object, objClass, clDesc, unshared);
} finally {
nestedLevels--;
}
}
// write for Enum Class Desc only, which is different from other classes
private ObjectStreamClass writeEnumDesc(Class theClass, ObjectStreamClass classDesc, boolean unshared)
throws IOException {
// write classDesc, classDesc for enum is different
// set flag for enum, the flag is (SC_SERIALIZABLE | SC_ENUM)
classDesc.setFlags((byte) (SC_SERIALIZABLE | SC_ENUM));
int previousHandle = -1;
if (unshared) {
previousHandle = objectsWritten.get(classDesc);
}
int handle = -1;
if (!unshared) {
handle = dumpCycle(classDesc);
}
if (handle == -1) {
Class classToWrite = classDesc.forClass();
// If we got here, it is a new (non-null) classDesc that will have
// to be registered as well
registerObjectWritten(classDesc);
output.writeByte(TC_CLASSDESC);
if (protocolVersion == PROTOCOL_VERSION_1) {
writeNewClassDesc(classDesc);
} else {
// So write...() methods can be used by
// subclasses during writeClassDescriptor()
primitiveTypes = output;
writeClassDescriptor(classDesc);
primitiveTypes = null;
}
// Extra class info (optional)
annotateClass(classToWrite);
drain(); // flush primitive types in the annotation
output.writeByte(TC_ENDBLOCKDATA);
// write super class
ObjectStreamClass superClassDesc = classDesc.getSuperclass();
if (superClassDesc != null) {
// super class is also enum
superClassDesc.setFlags((byte) (SC_SERIALIZABLE | SC_ENUM));
writeEnumDesc(superClassDesc.forClass(), superClassDesc, unshared);
} else {
output.writeByte(TC_NULL);
}
if (unshared) {
// remove reference to unshared object
removeUnsharedReference(classDesc, previousHandle);
}
}
return classDesc;
}
private int writeNewEnum(Object object, Class theClass, boolean unshared) throws IOException {
// write new Enum
EmulatedFieldsForDumping originalCurrentPutField = currentPutField; // save
// null it, to make sure one will be computed if needed
currentPutField = null;
output.writeByte(TC_ENUM);
while (theClass != null && !theClass.isEnum()) {
// write enum only
theClass = theClass.getSuperclass();
}
ObjectStreamClass classDesc = ObjectStreamClass.lookup(theClass);
writeEnumDesc(theClass, classDesc, unshared);
int previousHandle = -1;
if (unshared) {
previousHandle = objectsWritten.get(object);
}
int handle = registerObjectWritten(object);
ObjectStreamField[] fields = classDesc.getSuperclass().fields();
// Only write field "name" for enum class, which is the second field of
// enum, that is fields[1]. Ignore all non-fields and fields.length < 2
if (fields != null && fields.length > 1) {
Field field = classDesc.getSuperclass().getReflectionField(fields[1]);
if (field == null) {
throw new NoSuchFieldError();
}
try {
String str = (String) field.get(object);
int strHandle = -1;
if (!unshared) {
strHandle = dumpCycle(str);
}
if (strHandle == -1) {
writeNewString(str, unshared);
}
} catch (IllegalAccessException iae) {
throw new AssertionError(iae);
}
}
if (unshared) {
// remove reference to unshared object
removeUnsharedReference(object, previousHandle);
}
currentPutField = originalCurrentPutField;
return handle;
}
/**
* Method to be overridden by subclasses to write {@code object} to the
* target stream.
*
* @param object
* the object to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
protected void writeObjectOverride(Object object) throws IOException {
if (!subclassOverridingImplementation) {
// Subclasses must override.
throw new IOException();
}
}
/**
* Writes a short (16 bit) to the target stream.
*
* @param value
* the short to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeShort(int value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeShort(value);
}
/**
* Writes the {@link ObjectOutputStream} header to the target stream.
*
* @throws IOException
* if an error occurs while writing to the target stream.
*/
protected void writeStreamHeader() throws IOException {
output.writeShort(STREAM_MAGIC);
output.writeShort(STREAM_VERSION);
}
/**
* Writes a string encoded with {@link DataInput modified UTF-8} to the
* target stream.
*
* @param value
* the string to write to the target stream.
* @throws IOException
* if an error occurs while writing to the target stream.
*/
public void writeUTF(String value) throws IOException {
checkWritePrimitiveTypes();
primitiveTypes.writeUTF(value);
}
}