package org.codehaus.jackson.map.ser;
import java.io.IOException;
import java.text.DateFormat;
import java.util.Date;
import org.codehaus.jackson.*;
import org.codehaus.jackson.node.ObjectNode;
import org.codehaus.jackson.schema.JsonSchema;
import org.codehaus.jackson.schema.SchemaAware;
import org.codehaus.jackson.map.*;
/**
* Default {@link SerializerProvider} implementation. Handles
* caching aspects of serializer handling; all construction details
* are delegated to {@link SerializerFactory} instance.
*
* One note about implementation: the main instance constructed will
* be so-called "blueprint" object, and will NOT be used during actual
* serialization. Rather, an "instance" instance is created so that
* state can be carried along, as well as to avoid synchronization
* during serializer access. Because of this, if sub-classing, one
* must override method {@link #createInstance}: if this is not done,
* an exception will get thrown as base class verifies that the
* instance has same class as the blueprint
* (instance.getClass() == blueprint.getClass()).
* Check is done to prevent weird bugs that would otherwise occur.
*/
public class StdSerializerProvider
extends SerializerProvider
{
/**
* Setting for determining whether mappings for "unknown classes" should be
* cached for faster resolution. Usually this isn't needed, but maybe it
* is in some cases?
*
* TODO: make configurable?
*/
final static boolean CACHE_UNKNOWN_MAPPINGS = false;
public final static JsonSerializer DEFAULT_NULL_KEY_SERIALIZER =
new FailingSerializer("Null key for a Map not allower in Json (use a converting NullKeySerializer?)");
public final static JsonSerializer DEFAULT_KEY_SERIALIZER = new StdKeySerializer();
public final static JsonSerializer DEFAULT_UNKNOWN_SERIALIZER = new JsonSerializer()
{
@Override
public void serialize(Object value, JsonGenerator jgen, SerializerProvider provider)
throws JsonMappingException
{
/* 18-Feb-2009, tatu: Let's suggest the most likely reason
* for failure to find a serializer
*/
throw new JsonMappingException("No serializer found for class "+value.getClass().getName()+" (and no bean properties discovered to create bean serializer)");
}
};
/*
////////////////////////////////////////////////////
// Configuration, factories
////////////////////////////////////////////////////
*/
final protected SerializerFactory _serializerFactory;
final protected SerializerCache _serializerCache;
/*
////////////////////////////////////////////////////
// Configuration, specialized serializers
////////////////////////////////////////////////////
*/
/**
* Serializer that gets called for values of types for which no
* serializers can be constructed.
*
* The default serializer will simply thrown an exception; a possible
* alternative that can be used would be
* {@link ToStringSerializer}.
*/
protected JsonSerializer _unknownTypeSerializer = DEFAULT_UNKNOWN_SERIALIZER;
/**
* Serializer used to output non-null keys of Maps (which will get
* output as Json Objects).
*/
protected JsonSerializer _keySerializer = DEFAULT_KEY_SERIALIZER;
/**
* Serializer used to output a null value. Default implementation
* writes nulls using {@link JsonGenerator#writeNull}.
*/
protected JsonSerializer _nullValueSerializer = BasicSerializerFactory.NullSerializer.instance;
/**
* Serializer used to (try to) output a null key, due to an entry of
* {@link java.util.Map} having null key.
* The default implementation will throw an exception if this happens;
* alternative implementation (like one that would write an Empty String)
* can be defined.
*/
protected JsonSerializer _nullKeySerializer = DEFAULT_NULL_KEY_SERIALIZER;
/*
////////////////////////////////////////////////////
// State, for non-blueprint instances
////////////////////////////////////////////////////
*/
/**
* For fast lookups, we will have a local non-shared read-only
* map that contains serializers previously fetched.
*/
protected final ReadOnlyClassToSerializerMap _knownSerializers;
/**
* Lazily acquired and instantiated formatter object: initialized
* first time it is needed, reused afterwards. Used via instances
* (not blueprints), so that access need not be thread-safe.
*/
protected DateFormat _dateFormat;
/*
////////////////////////////////////////////////////
// Life-cycle
////////////////////////////////////////////////////
*/
/**
* Constructor for creating master (or "blue-print") provider object,
* which is only used as the template for constructing per-binding
* instances.
*/
public StdSerializerProvider()
{
super(null);
_serializerFactory = null;
_serializerCache = new SerializerCache();
// Blueprints doesn't have access to any serializers...
_knownSerializers = null;
}
/**
* "Copy-constructor", used from {@link #createInstance} (or by
* sub-classes)
*
* @param src Blueprint object used as the baseline for this instance
*/
protected StdSerializerProvider(SerializationConfig config,
StdSerializerProvider src,
SerializerFactory f)
{
super(config);
if (config == null) {
throw new NullPointerException();
}
_serializerFactory = f;
_serializerCache = src._serializerCache;
_unknownTypeSerializer = src._unknownTypeSerializer;
_keySerializer = src._keySerializer;
_nullValueSerializer = src._nullValueSerializer;
_nullKeySerializer = src._nullKeySerializer;
/* Non-blueprint instances do have a read-only map; one that doesn't
* need synchronization for lookups.
*/
_knownSerializers = _serializerCache.getReadOnlyLookupMap();
}
/**
* Overridable method, used to create a non-blueprint instances from the blueprint.
* This is needed to retain state during serialization.
*/
protected StdSerializerProvider createInstance(SerializationConfig config, SerializerFactory jsf)
{
return new StdSerializerProvider(config, this, jsf);
}
/*
////////////////////////////////////////////////////
// Methods to be called by JavaTypeMapper
////////////////////////////////////////////////////
*/
@Override
public final void serializeValue(SerializationConfig config,
JsonGenerator jgen, Object value,
SerializerFactory jsf)
throws IOException, JsonGenerationException
{
if (jsf == null) {
throw new IllegalArgumentException("Can not pass null serializerFactory");
}
/* First: we need a separate instance, which will hold a copy of the
* non-shared ("local") read-only lookup Map for fast
* class-to-serializer lookup
*/
StdSerializerProvider inst = createInstance(config, jsf);
// sanity check to avoid weird errors; to ensure sub-classes do override createInstance
if (inst.getClass() != getClass()) {
throw new IllegalStateException("Broken serializer provider: createInstance returned instance of type "+inst.getClass()+"; blueprint of type "+getClass());
}
// And then we can do actual serialization, through the instance
inst._serializeValue(jgen, value);
}
@Override
public JsonSchema generateJsonSchema(Class type, SerializationConfig config, SerializerFactory jsf)
throws JsonMappingException
{
if (type == null) {
throw new IllegalArgumentException("A class must be provided.");
}
/* First: we need a separate instance, which will hold a copy of the
* non-shared ("local") read-only lookup Map for fast
* class-to-serializer lookup
*/
StdSerializerProvider inst = createInstance(config, jsf);
// sanity check to avoid weird errors; to ensure sub-classes do override createInstance
if (inst.getClass() != getClass()) {
throw new IllegalStateException("Broken serializer provider: createInstance returned instance of type "+inst.getClass()+"; blueprint of type "+getClass());
}
JsonSerializer ser = inst.findValueSerializer(type);
JsonNode schemaNode = (ser instanceof SchemaAware) ?
((SchemaAware) ser).getSchema(inst, null) :
JsonSchema.getDefaultSchemaNode();
if (!(schemaNode instanceof ObjectNode)) {
throw new IllegalArgumentException("Class " + type.getName() +
" would not be serialized as a JSON object and therefore has no schema.");
}
return new JsonSchema((ObjectNode) schemaNode);
}
public boolean hasSerializerFor(SerializationConfig config,
Class cls, SerializerFactory jsf)
{
return createInstance(config, jsf)._findExplicitSerializer(cls) != null;
}
/**
* Method called on the actual non-blueprint provider instance object,
* to kick off the serialization.
*/
protected void _serializeValue(JsonGenerator jgen, Object value)
throws IOException, JsonProcessingException
{
JsonSerializer ser = (value == null) ?
getNullValueSerializer() : findValueSerializer(value.getClass());
try {
ser.serialize(value, jgen, this);
} catch (IOException ioe) {
/* As per [JACKSON-99], should not wrap IOException or its
* sub-classes (like JsonProcessingException, JsonMappingException)
*/
throw ioe;
} catch (Exception e) {
// but others are wrapped
String msg = e.getMessage();
if (msg == null) {
msg = "[no message for "+e.getClass().getName()+"]";
}
throw new JsonMappingException(msg, e);
}
}
/*
////////////////////////////////////////////////////
// Configuration methods
////////////////////////////////////////////////////
*/
public void setKeySerializer(JsonSerializer ks)
{
if (ks == null) {
throw new IllegalArgumentException("Can not pass null JsonSerializer");
}
_keySerializer = ks;
}
public void setNullValueSerializer(JsonSerializer nvs)
{
if (nvs == null) {
throw new IllegalArgumentException("Can not pass null JsonSerializer");
}
_nullValueSerializer = nvs;
}
public void setNullKeySerializer(JsonSerializer nks)
{
if (nks == null) {
throw new IllegalArgumentException("Can not pass null JsonSerializer");
}
_nullKeySerializer = nks;
}
/*
////////////////////////////////////////////////////
// Abstract method impls, locating serializers
////////////////////////////////////////////////////
*/
@Override
public JsonSerializer findValueSerializer(Class type)
throws JsonMappingException
{
// Fast lookup from local lookup thingy works?
JsonSerializer ser = _knownSerializers.get(type);
if (ser != null) {
return ser;
}
// If not, maybe shared map already has it?
ser = _serializerCache.findSerializer(type);
if (ser != null) {
return ser;
}
// If neither, must create
ser = _createAndCacheSerializer(type);
// Not found? Must use the unknown type serializer
/* Couldn't create? Need to return the fallback serializer, which
* most likely will report an error: but one question is whether
* we should cache it?
*/
if (ser == null) {
ser = getUnknownTypeSerializer(type);
// Should this be added to lookups?
if (CACHE_UNKNOWN_MAPPINGS) {
_serializerCache.addSerializer(type, ser);
}
}
return ser;
}
@Override
public JsonSerializer getKeySerializer()
{
return _keySerializer;
}
@Override
public JsonSerializer getNullKeySerializer() {
return _nullKeySerializer;
}
@Override
public JsonSerializer getNullValueSerializer() {
return _nullValueSerializer;
}
@Override
public JsonSerializer getUnknownTypeSerializer(Class unknownType) {
return _unknownTypeSerializer;
}
/*
////////////////////////////////////////////////////
// Abstract method impls, convenience methods
////////////////////////////////////////////////////
*/
/**
* @param timestamp Millisecond timestamp that defines date, if available;
*/
@Override
public final void defaultSerializeDateValue(long timestamp, JsonGenerator jgen)
throws IOException, JsonProcessingException
{
// [JACKSON-87]: Support both numeric timestamps and textual
if (isEnabled(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS)) {
jgen.writeNumber(timestamp);
} else {
if (_dateFormat == null) {
// must create a clone since Formats are not thread-safe:
_dateFormat = (DateFormat)_config.getDateFormat().clone();
}
jgen.writeString(_dateFormat.format(new Date(timestamp)));
}
}
@Override
public final void defaultSerializeDateValue(Date date, JsonGenerator jgen)
throws IOException, JsonProcessingException
{
// [JACKSON-87]: Support both numeric timestamps and textual
if (isEnabled(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS)) {
jgen.writeNumber(date.getTime());
} else {
if (_dateFormat == null) {
DateFormat blueprint = _config.getDateFormat();
// must create a clone since Formats are not thread-safe:
_dateFormat = (DateFormat)blueprint.clone();
}
jgen.writeString(_dateFormat.format(date));
}
}
/*
////////////////////////////////////////////////////////////////
// Helper methods: can be overridden by sub-classes
////////////////////////////////////////////////////////////////
*/
/**
* Method that will try to find a serializer, either from cache
* or by constructing one; but will not return an "unknown" serializer
* if this can not be done but rather returns null.
*
* @return Serializer if one can be found, null if not.
*/
protected JsonSerializer _findExplicitSerializer(Class type)
{
// Fast lookup from local lookup thingy works?
JsonSerializer ser = _knownSerializers.get(type);
if (ser != null) {
return ser;
}
// If not, maybe shared map already has it?
ser = _serializerCache.findSerializer(type);
if (ser != null) {
return ser;
}
try {
return _createAndCacheSerializer(type);
} catch (Exception e) {
return null;
}
}
/**
* Method that will try to construct a value aerializer; and if
* one is succesfully created, cache it for reuse.
*/
protected JsonSerializer _createAndCacheSerializer(Class type)
throws JsonMappingException
{
JsonSerializer ser;
try {
ser = _createSerializer(type);
} catch (IllegalArgumentException iae) {
/* We better only expose checked exceptions, since those
* are what caller is expected to handle
*/
throw new JsonMappingException(iae.getMessage(), null, iae);
}
if (ser != null) {
_serializerCache.addSerializer(type, ser);
/* Finally: some serializers want to do post-processing, after
* getting registered (to handle cyclic deps).
*/
if (ser instanceof ResolvableSerializer) {
_resolveSerializer((ResolvableSerializer)ser);
}
}
return ser;
}
@SuppressWarnings("unchecked")
protected JsonSerializer _createSerializer(Class type)
throws JsonMappingException
{
/* 10-Dec-2008, tatu: Is there a possibility of infinite loops
* here? Shouldn't be, given that we do not pass back-reference
* to this provider. But if there is, we'd need to sync calls,
* and keep track of creation chain to look for loops -- fairly
* easy to do, but won't add yet since it seems unnecessary.
*/
return (JsonSerializer)_serializerFactory.createSerializer(type, _config);
}
protected void _resolveSerializer(ResolvableSerializer ser)
throws JsonMappingException
{
ser.resolve(this);
}
}
