/*
* Copyright (C) 2007, 2009, 2011 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 10. April 2007 by Guilherme Silveira
*/
package com.thoughtworks.xstream.converters.reflection;
import com.thoughtworks.xstream.core.Caching;
import com.thoughtworks.xstream.core.util.OrderRetainingMap;
import com.thoughtworks.xstream.io.StreamException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
/**
* The default implementation for sorting fields. Invoke registerFieldOrder in order to set the
* field order for an specific type.
*
* @author Guilherme Silveira
* @since 1.2.2
*/
public class SortableFieldKeySorter implements FieldKeySorter, Caching {
private final Map map = new HashMap();
public Map sort(Class type, Map keyedByFieldKey) {
if (map.containsKey(type)) {
Map result = new OrderRetainingMap();
FieldKey[] fieldKeys = (FieldKey[])keyedByFieldKey.keySet().toArray(
new FieldKey[keyedByFieldKey.size()]);
Arrays.sort(fieldKeys, (Comparator)map.get(type));
for (int i = 0; i < fieldKeys.length; i++ ) {
result.put(fieldKeys[i], keyedByFieldKey.get(fieldKeys[i]));
}
return result;
} else {
return keyedByFieldKey;
}
}
/**
* Registers the field order to use for a specific type. This will not affect any of the
* type's super or sub classes. If you skip a field which will be serialized, XStream will
* thrown an StreamException during the serialization process.
*
* @param type the type
* @param fields the field order
*/
public void registerFieldOrder(Class type, String[] fields) {
map.put(type, new FieldComparator(fields));
}
private class FieldComparator implements Comparator {
private final String[] fieldOrder;
public FieldComparator(String[] fields) {
this.fieldOrder = fields;
}
public int compare(String first, String second) {
int firstPosition = -1, secondPosition = -1;
for (int i = 0; i < fieldOrder.length; i++ ) {
if (fieldOrder[i].equals(first)) {
firstPosition = i;
}
if (fieldOrder[i].equals(second)) {
secondPosition = i;
}
}
if (firstPosition == -1 || secondPosition == -1) {
// field not defined!!!
throw new StreamException(
"You have not given XStream a list of all fields to be serialized.");
}
return firstPosition - secondPosition;
}
public int compare(Object firstObject, Object secondObject) {
FieldKey first = (FieldKey)firstObject, second = (FieldKey)secondObject;
return compare(first.getFieldName(), second.getFieldName());
}
}
public void flushCache() {
map.clear();
}
}