com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter Maven / Gradle / Ivy
/*
* Copyright (C) 2004, 2005, 2006 Joe Walnes.
* Copyright (C) 2006, 2007, 2008 XStream Committers.
* All rights reserved.
*
* The software in this package is published under the terms of the BSD
* style license a copy of which has been included with this distribution in
* the LICENSE.txt file.
*
* Created on 02. March 2006 by Joerg Schaible
*/
package com.thoughtworks.xstream.converters.reflection;
import com.thoughtworks.xstream.converters.ConversionException;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.SingleValueConverter;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.core.util.HierarchicalStreams;
import com.thoughtworks.xstream.core.util.Primitives;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.ExtendedHierarchicalStreamWriterHelper;
import com.thoughtworks.xstream.mapper.Mapper;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
public abstract class AbstractReflectionConverter implements Converter {
protected final ReflectionProvider reflectionProvider;
protected final Mapper mapper;
protected transient SerializationMethodInvoker serializationMethodInvoker;
private transient ReflectionProvider pureJavaReflectionProvider;
public AbstractReflectionConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
this.mapper = mapper;
this.reflectionProvider = reflectionProvider;
serializationMethodInvoker = new SerializationMethodInvoker();
}
public void marshal(Object original, final HierarchicalStreamWriter writer, final MarshallingContext context) {
final Object source = serializationMethodInvoker.callWriteReplace(original);
if (source.getClass() != original.getClass()) {
String attributeName = mapper.aliasForSystemAttribute("resolves-to");
if (attributeName != null) {
writer.addAttribute(attributeName, mapper.serializedClass(source.getClass()));
}
context.convertAnother(source);
} else {
doMarshal(source, writer, context);
}
}
protected void doMarshal(final Object source, final HierarchicalStreamWriter writer, final MarshallingContext context) {
final Set seenFields = new HashSet();
final Map defaultFieldDefinition = new HashMap();
// Attributes might be preferred to child elements ...
reflectionProvider.visitSerializableFields(source, new ReflectionProvider.Visitor() {
public void visit(String fieldName, Class type, Class definedIn, Object value) {
if (!mapper.shouldSerializeMember(definedIn, fieldName)) {
return;
}
if (!defaultFieldDefinition.containsKey(fieldName)) {
Class lookupType = source.getClass();
// See XSTR-457 and OmitFieldsTest
// if (definedIn != source.getClass() && !mapper.shouldSerializeMember(lookupType, fieldName)) {
// lookupType = definedIn;
// }
defaultFieldDefinition.put(fieldName, reflectionProvider.getField(lookupType, fieldName));
}
SingleValueConverter converter = mapper.getConverterFromItemType(fieldName, type, definedIn);
if (converter != null) {
if (value != null) {
if (seenFields.contains(fieldName)) {
throw new ConversionException("Cannot write field with name '" + fieldName
+ "' twice as attribute for object of type " + source.getClass().getName());
}
final String str = converter.toString(value);
if (str != null) {
writer.addAttribute(mapper.aliasForAttribute(mapper.serializedMember(definedIn, fieldName)), str);
}
}
// TODO: name is not enough, need also "definedIn"!
seenFields.add(fieldName);
}
}
});
// Child elements not covered already processed as attributes ...
reflectionProvider.visitSerializableFields(source, new ReflectionProvider.Visitor() {
public void visit(String fieldName, Class fieldType, Class definedIn, Object newObj) {
if (!mapper.shouldSerializeMember(definedIn, fieldName)) {
return;
}
if (!seenFields.contains(fieldName) && newObj != null) {
Mapper.ImplicitCollectionMapping mapping = mapper.getImplicitCollectionDefForFieldName(source.getClass(), fieldName);
if (mapping != null) {
if (mapping.getItemFieldName() != null) {
Collection list = (Collection) newObj;
for (Iterator iter = list.iterator(); iter.hasNext();) {
Object obj = iter.next();
writeField(fieldName, obj == null ? mapper.serializedClass(null) : mapping.getItemFieldName(), mapping.getItemType(), definedIn, obj);
}
} else {
context.convertAnother(newObj);
}
} else {
writeField(fieldName, null, fieldType, definedIn, newObj);
}
}
}
private void writeField(String fieldName, String aliasName, Class fieldType, Class definedIn, Object newObj) {
ExtendedHierarchicalStreamWriterHelper.startNode(writer, aliasName != null ? aliasName : mapper.serializedMember(source.getClass(), fieldName), fieldType);
if (newObj != null) {
Class actualType = newObj.getClass();
Class defaultType = mapper.defaultImplementationOf(fieldType);
if (!actualType.equals(defaultType)) {
String serializedClassName = mapper.serializedClass(actualType);
if (!serializedClassName.equals(mapper.serializedClass(defaultType))) {
String attributeName = mapper.aliasForSystemAttribute("class");
if (attributeName != null) {
writer.addAttribute(attributeName, serializedClassName);
}
}
}
final Field defaultField = (Field)defaultFieldDefinition.get(fieldName);
if (defaultField.getDeclaringClass() != definedIn) {
String attributeName = mapper.aliasForSystemAttribute("defined-in");
if (attributeName != null) {
writer.addAttribute(attributeName, mapper.serializedClass(definedIn));
}
}
Field field = reflectionProvider.getField(definedIn,fieldName);
marshallField(context, newObj, field);
}
writer.endNode();
}
});
}
protected void marshallField(final MarshallingContext context, Object newObj, Field field) {
context.convertAnother(newObj, mapper.getLocalConverter(field.getDeclaringClass(), field.getName()));
}
public Object unmarshal(final HierarchicalStreamReader reader, final UnmarshallingContext context) {
Object result = instantiateNewInstance(reader, context);
result = doUnmarshal(result, reader, context);
return serializationMethodInvoker.callReadResolve(result);
}
public Object doUnmarshal(final Object result, final HierarchicalStreamReader reader, final UnmarshallingContext context) {
final SeenFields seenFields = new SeenFields();
Iterator it = reader.getAttributeNames();
// Process attributes before recursing into child elements.
while (it.hasNext()) {
String attrAlias = (String) it.next();
String attrName = mapper.realMember(result.getClass(), mapper.attributeForAlias(attrAlias));
Class classDefiningField = determineWhichClassDefinesField(reader);
boolean fieldExistsInClass = reflectionProvider.fieldDefinedInClass(attrName, result.getClass());
if (fieldExistsInClass) {
Field field = reflectionProvider.getField(result.getClass(), attrName);
if (Modifier.isTransient(field.getModifiers()) && ! shouldUnmarshalTransientFields()) {
continue;
}
SingleValueConverter converter = mapper.getConverterFromAttribute(field.getDeclaringClass(), attrName, field.getType());
Class type = field.getType();
if (converter != null) {
Object value = converter.fromString(reader.getAttribute(attrAlias));
if (type.isPrimitive()) {
type = Primitives.box(type);
}
if (value != null && !type.isAssignableFrom(value.getClass())) {
throw new ConversionException("Cannot convert type " + value.getClass().getName() + " to type " + type.getName());
}
reflectionProvider.writeField(result, attrName, value, classDefiningField);
seenFields.add(classDefiningField, attrName);
}
}
}
Map implicitCollectionsForCurrentObject = null;
while (reader.hasMoreChildren()) {
reader.moveDown();
String originalNodeName = reader.getNodeName();
String fieldName = mapper.realMember(result.getClass(), originalNodeName);
Mapper.ImplicitCollectionMapping implicitCollectionMapping = mapper.getImplicitCollectionDefForFieldName(result.getClass(), fieldName);
Class classDefiningField = determineWhichClassDefinesField(reader);
boolean fieldExistsInClass = implicitCollectionMapping == null && reflectionProvider.fieldDefinedInClass(fieldName, result.getClass());
Class type = implicitCollectionMapping == null
? determineType(reader, fieldExistsInClass, result, fieldName, classDefiningField)
: implicitCollectionMapping.getItemType();
final Object value;
if (fieldExistsInClass) {
Field field = reflectionProvider.getField(classDefiningField != null ? classDefiningField : result.getClass(), fieldName);
if (Modifier.isTransient(field.getModifiers()) && !shouldUnmarshalTransientFields()) {
reader.moveUp();
continue;
}
value = unmarshallField(context, result, type, field);
// TODO the reflection provider should have returned the proper field in first place ....
Class definedType = reflectionProvider.getFieldType(result, fieldName, classDefiningField);
if (!definedType.isPrimitive()) {
type = definedType;
}
} else {
value = type != null ? context.convertAnother(result, type) : null;
}
if (value != null && !type.isAssignableFrom(value.getClass())) {
throw new ConversionException("Cannot convert type " + value.getClass().getName() + " to type " + type.getName());
}
if (fieldExistsInClass) {
reflectionProvider.writeField(result, fieldName, value, classDefiningField);
seenFields.add(classDefiningField, fieldName);
} else if (type != null) {
implicitCollectionsForCurrentObject = writeValueToImplicitCollection(context, value, implicitCollectionsForCurrentObject, result, originalNodeName);
}
reader.moveUp();
}
return result;
}
protected Object unmarshallField(final UnmarshallingContext context, final Object result, Class type, Field field) {
return context.convertAnother(result, type, mapper.getLocalConverter(field.getDeclaringClass(), field.getName()));
}
protected boolean shouldUnmarshalTransientFields() {
return false;
}
private Map writeValueToImplicitCollection(UnmarshallingContext context, Object value,
Map implicitCollections, Object result, String itemFieldName) {
String fieldName = mapper.getFieldNameForItemTypeAndName(
context.getRequiredType(), value != null ? value.getClass() : Mapper.Null.class,
itemFieldName);
if (fieldName != null) {
if (implicitCollections == null) {
implicitCollections = new HashMap(); // lazy instantiation
}
Collection collection = (Collection)implicitCollections.get(fieldName);
if (collection == null) {
Class fieldType = mapper.defaultImplementationOf(reflectionProvider
.getFieldType(result, fieldName, null));
if (!Collection.class.isAssignableFrom(fieldType)) {
throw new ObjectAccessException("Field "
+ fieldName
+ " of "
+ result.getClass().getName()
+ " is configured for an implicit Collection, but field is of type "
+ fieldType.getName());
}
if (pureJavaReflectionProvider == null) {
pureJavaReflectionProvider = new PureJavaReflectionProvider();
}
collection = (Collection)pureJavaReflectionProvider.newInstance(fieldType);
reflectionProvider.writeField(result, fieldName, collection, null);
implicitCollections.put(fieldName, collection);
}
collection.add(value);
} else {
throw new ConversionException("Element "
+ itemFieldName
+ " of type "
+ value.getClass().getName()
+ " is not defined as field in type "
+ result.getClass().getName());
}
return implicitCollections;
}
private Class determineWhichClassDefinesField(HierarchicalStreamReader reader) {
String attributeName = mapper.aliasForSystemAttribute("defined-in");
String definedIn = attributeName == null ? null : reader.getAttribute(attributeName);
return definedIn == null ? null : mapper.realClass(definedIn);
}
protected Object instantiateNewInstance(HierarchicalStreamReader reader, UnmarshallingContext context) {
String attributeName = mapper.aliasForSystemAttribute("resolves-to");
String readResolveValue = attributeName == null ? null : reader.getAttribute(attributeName);
Object currentObject = context.currentObject();
if (currentObject != null) {
return currentObject;
} else if (readResolveValue != null) {
return reflectionProvider.newInstance(mapper.realClass(readResolveValue));
} else {
return reflectionProvider.newInstance(context.getRequiredType());
}
}
private static class SeenFields {
private Set seen = new HashSet();
public void add(Class definedInCls, String fieldName) {
String uniqueKey = fieldName;
if (definedInCls != null) {
uniqueKey += " [" + definedInCls.getName() + "]";
}
if (seen.contains(uniqueKey)) {
throw new DuplicateFieldException(uniqueKey);
} else {
seen.add(uniqueKey);
}
}
}
private Class determineType(HierarchicalStreamReader reader, boolean validField, Object result, String fieldName, Class definedInCls) {
String classAttribute = HierarchicalStreams.readClassAttribute(reader, mapper);
if (classAttribute != null) {
return mapper.realClass(classAttribute);
} else if (!validField) {
Class itemType = mapper.getItemTypeForItemFieldName(result.getClass(), fieldName);
if (itemType != null) {
return itemType;
} else {
String originalNodeName = reader.getNodeName();
if (definedInCls == null) {
for(definedInCls = result.getClass(); definedInCls != null; definedInCls = definedInCls.getSuperclass()) {
if (!mapper.shouldSerializeMember(definedInCls, originalNodeName)) {
return null;
}
}
}
return mapper.realClass(originalNodeName);
}
} else {
return mapper.defaultImplementationOf(reflectionProvider.getFieldType(result, fieldName, definedInCls));
}
}
private Object readResolve() {
serializationMethodInvoker = new SerializationMethodInvoker();
return this;
}
public static class DuplicateFieldException extends ConversionException {
public DuplicateFieldException(String msg) {
super(msg);
add("duplicate-field", msg);
}
}
}
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