com.thoughtworks.xstream.converters.reflection.FieldDictionary Maven / Gradle / Ivy
/*
* Copyright (C) 2004, 2005, 2006 Joe Walnes.
* Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 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 14. May 2004 by Joe Walnes
*/
package com.thoughtworks.xstream.converters.reflection;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import com.thoughtworks.xstream.core.Caching;
import com.thoughtworks.xstream.core.JVM;
import com.thoughtworks.xstream.core.util.OrderRetainingMap;
/**
* A field dictionary instance caches information about classes fields.
*
* @author Joe Walnes
* @author Jörg Schaible
* @author Guilherme Silveira
*/
public class FieldDictionary implements Caching {
private static final DictionaryEntry OBJECT_DICTIONARY_ENTRY = new DictionaryEntry(Collections.EMPTY_MAP,
Collections.EMPTY_MAP);
private transient Map dictionaryEntries;
private final FieldKeySorter sorter;
public FieldDictionary() {
this(new ImmutableFieldKeySorter());
}
public FieldDictionary(final FieldKeySorter sorter) {
this.sorter = sorter;
init();
}
private void init() {
dictionaryEntries = new HashMap();
}
/**
* Returns an iterator for all fields for some class
*
* @param cls the class you are interested on
* @return an iterator for its fields
* @deprecated As of 1.3, use {@link #fieldsFor(Class)} instead
*/
public Iterator serializableFieldsFor(final Class cls) {
return fieldsFor(cls);
}
/**
* Returns an iterator for all fields for some class
*
* @param cls the class you are interested on
* @return an iterator for its fields
*/
public Iterator fieldsFor(final Class cls) {
return buildMap(cls, true).values().iterator();
}
/**
* Returns an specific field of some class. If definedIn is null, it searches for the field named 'name' inside the
* class cls. If definedIn is different than null, tries to find the specified field name in the specified class cls
* which should be defined in class definedIn (either equals cls or a one of it's superclasses)
*
* @param cls the class where the field is to be searched
* @param name the field name
* @param definedIn the superclass (or the class itself) of cls where the field was defined
* @return the field itself
* @throws ObjectAccessException if no field can be found
*/
public Field field(final Class cls, final String name, final Class definedIn) {
final Field field = fieldOrNull(cls, name, definedIn);
if (field == null) {
throw new MissingFieldException(cls.getName(), name);
} else {
return field;
}
}
/**
* Returns an specific field of some class. If definedIn is null, it searches for the field named 'name' inside the
* class cls. If definedIn is different than null, tries to find the specified field name in the specified class cls
* which should be defined in class definedIn (either equals cls or a one of it's superclasses)
*
* @param cls the class where the field is to be searched
* @param name the field name
* @param definedIn the superclass (or the class itself) of cls where the field was defined
* @return the field itself or null
* @since 1.4
*/
public Field fieldOrNull(final Class cls, final String name, final Class definedIn) {
final Map fields = buildMap(cls, definedIn != null);
final Field field = (Field)fields.get(definedIn != null
? (Object)new FieldKey(name, definedIn, -1)
: (Object)name);
return field;
}
private Map buildMap(final Class type, final boolean tupleKeyed) {
Class cls = type;
DictionaryEntry lastDictionaryEntry = null;
final LinkedList superClasses = new LinkedList();
while (lastDictionaryEntry == null) {
if (Object.class.equals(cls) || cls == null) {
lastDictionaryEntry = OBJECT_DICTIONARY_ENTRY;
} else {
lastDictionaryEntry = getDictionaryEntry(cls);
}
if (lastDictionaryEntry == null) {
superClasses.addFirst(cls);
cls = cls.getSuperclass();
}
}
for (final Iterator iter = superClasses.iterator(); iter.hasNext();) {
cls = (Class)iter.next();
DictionaryEntry newDictionaryEntry = buildDictionaryEntryForClass(cls, lastDictionaryEntry);
synchronized (this) {
final DictionaryEntry concurrentEntry = getDictionaryEntry(cls);
if (concurrentEntry == null) {
dictionaryEntries.put(cls, newDictionaryEntry);
} else {
newDictionaryEntry = concurrentEntry;
}
}
lastDictionaryEntry = newDictionaryEntry;
}
return tupleKeyed ? lastDictionaryEntry.getKeyedByFieldKey() : lastDictionaryEntry.getKeyedByFieldName();
}
private DictionaryEntry buildDictionaryEntryForClass(final Class cls, final DictionaryEntry lastDictionaryEntry) {
final Map keyedByFieldName = new HashMap(lastDictionaryEntry.getKeyedByFieldName());
final Map keyedByFieldKey = new OrderRetainingMap(lastDictionaryEntry.getKeyedByFieldKey());
final Field[] fields = cls.getDeclaredFields();
if (JVM.reverseFieldDefinition()) {
for (int i = fields.length >> 1; i-- > 0;) {
final int idx = fields.length - i - 1;
final Field field = fields[i];
fields[i] = fields[idx];
fields[idx] = field;
}
}
for (int i = 0; i < fields.length; i++) {
final Field field = fields[i];
if (!field.isAccessible()) {
field.setAccessible(true);
}
final FieldKey fieldKey = new FieldKey(field.getName(), field.getDeclaringClass(), i);
final Field existent = (Field)keyedByFieldName.get(field.getName());
if (existent == null
// do overwrite statics
|| (existent.getModifiers() & Modifier.STATIC) != 0
// overwrite non-statics with non-statics only
|| (existent != null && (field.getModifiers() & Modifier.STATIC) == 0)) {
keyedByFieldName.put(field.getName(), field);
}
keyedByFieldKey.put(fieldKey, field);
}
final Map sortedFieldKeys = sorter.sort(cls, keyedByFieldKey);
return new DictionaryEntry(keyedByFieldName, sortedFieldKeys);
}
private synchronized DictionaryEntry getDictionaryEntry(final Class cls) {
return (DictionaryEntry)dictionaryEntries.get(cls);
}
public synchronized void flushCache() {
dictionaryEntries.clear();
if (sorter instanceof Caching) {
((Caching)sorter).flushCache();
}
}
protected Object readResolve() {
init();
return this;
}
private static final class DictionaryEntry {
private final Map keyedByFieldName;
private final Map keyedByFieldKey;
public DictionaryEntry(final Map keyedByFieldName, final Map keyedByFieldKey) {
super();
this.keyedByFieldName = keyedByFieldName;
this.keyedByFieldKey = keyedByFieldKey;
}
public Map getKeyedByFieldName() {
return keyedByFieldName;
}
public Map getKeyedByFieldKey() {
return keyedByFieldKey;
}
}
}
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