/**
* 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 org.apache.camel.impl.converter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.camel.Exchange;
import org.apache.camel.NoTypeConversionAvailableException;
import org.apache.camel.TypeConverter;
import org.apache.camel.spi.Injector;
import org.apache.camel.spi.TypeConverterAware;
import org.apache.camel.util.FactoryFinder;
import org.apache.camel.util.NoFactoryAvailableException;
import org.apache.camel.util.ObjectHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import static org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException;
/**
* Default implementation of a type converter registry used for
* <a href="http://activemq.apache.org/camel/type-converter.html">type converters</a> in Camel.
*
* @version $Revision: 699766 $
*/
public class DefaultTypeConverter implements TypeConverter, TypeConverterRegistry {
private static final transient Log LOG = LogFactory.getLog(DefaultTypeConverter.class);
private final Map<TypeMapping, TypeConverter> typeMappings = new ConcurrentHashMap<TypeMapping, TypeConverter>();
private Injector injector;
private List<TypeConverterLoader> typeConverterLoaders = new ArrayList<TypeConverterLoader>();
private List<TypeConverter> fallbackConverters = new ArrayList<TypeConverter>();
private boolean loaded;
public DefaultTypeConverter(Injector injector) {
typeConverterLoaders.add(new AnnotationTypeConverterLoader());
this.injector = injector;
addFallbackConverter(new AsyncProcessorTypeConverter());
addFallbackConverter(new PropertyEditorTypeConverter());
addFallbackConverter(new ToStringTypeConverter());
addFallbackConverter(new ArrayTypeConverter());
addFallbackConverter(new EnumTypeConverter());
}
public <T> T convertTo(Class<T> type, Object value) {
return convertTo(type, null, value);
}
@SuppressWarnings("unchecked")
public <T> T convertTo(Class<T> type, Exchange exchange, Object value) {
if (LOG.isTraceEnabled()) {
LOG.trace("Converting " + (value == null ? "null" : value.getClass().getCanonicalName())
+ " -> " + type.getCanonicalName() + " with value: " + value);
}
if (value == null) {
// lets avoid NullPointerException when converting to boolean for null values
if (boolean.class.isAssignableFrom(type)) {
return (T) Boolean.FALSE;
}
return null;
}
// same instance type
if (type.isInstance(value)) {
return type.cast(value);
}
// make sure we have loaded the converters
checkLoaded();
// try to find a suitable type converter
TypeConverter converter = getOrFindTypeConverter(type, value);
if (converter != null) {
T rc = converter.convertTo(type, exchange, value);
if (rc != null) {
return rc;
}
}
// fallback converters
for (TypeConverter fallback : fallbackConverters) {
T rc = fallback.convertTo(type, exchange, value);
if (rc != null) {
return rc;
}
}
// primitives
if (type.isPrimitive()) {
Class primitiveType = ObjectHelper.convertPrimitiveTypeToWrapperType(type);
if (primitiveType != type) {
return (T) convertTo(primitiveType, exchange, value);
}
}
// Could not find suitable conversion
throw new NoTypeConversionAvailableException(value, type);
}
public void addTypeConverter(Class toType, Class fromType, TypeConverter typeConverter) {
TypeMapping key = new TypeMapping(toType, fromType);
synchronized (typeMappings) {
TypeConverter converter = typeMappings.get(key);
if (converter != null) {
LOG.warn("Overriding type converter from: " + converter + " to: " + typeConverter);
}
typeMappings.put(key, typeConverter);
}
}
public void addFallbackConverter(TypeConverter converter) {
fallbackConverters.add(converter);
if (converter instanceof TypeConverterAware) {
TypeConverterAware typeConverterAware = (TypeConverterAware)converter;
typeConverterAware.setTypeConverter(this);
}
}
public TypeConverter getTypeConverter(Class toType, Class fromType) {
TypeMapping key = new TypeMapping(toType, fromType);
return typeMappings.get(key);
}
public Injector getInjector() {
return injector;
}
public void setInjector(Injector injector) {
this.injector = injector;
}
protected <T> TypeConverter getOrFindTypeConverter(Class toType, Object value) {
Class fromType = null;
if (value != null) {
fromType = value.getClass();
}
TypeMapping key = new TypeMapping(toType, fromType);
TypeConverter converter;
synchronized (typeMappings) {
converter = typeMappings.get(key);
if (converter == null) {
converter = findTypeConverter(toType, fromType, value);
if (converter != null) {
typeMappings.put(key, converter);
}
}
}
return converter;
}
/**
* Tries to auto-discover any available type converters
*/
protected TypeConverter findTypeConverter(Class toType, Class fromType, Object value) {
// lets try the super classes of the from type
if (fromType != null) {
Class fromSuperClass = fromType.getSuperclass();
if (fromSuperClass != null && !fromSuperClass.equals(Object.class)) {
TypeConverter converter = getTypeConverter(toType, fromSuperClass);
if (converter == null) {
converter = findTypeConverter(toType, fromSuperClass, value);
}
if (converter != null) {
return converter;
}
}
for (Class type : fromType.getInterfaces()) {
TypeConverter converter = getTypeConverter(toType, type);
if (converter != null) {
return converter;
}
}
// lets test for arrays
if (fromType.isArray() && !fromType.getComponentType().isPrimitive()) {
// TODO can we try walking the inheritance-tree for the element types?
if (!fromType.equals(Object[].class)) {
fromSuperClass = Object[].class;
TypeConverter converter = getTypeConverter(toType, fromSuperClass);
if (converter == null) {
converter = findTypeConverter(toType, fromSuperClass, value);
}
if (converter != null) {
return converter;
}
}
}
// lets test for Object based converters
if (!fromType.equals(Object.class)) {
TypeConverter converter = getTypeConverter(toType, Object.class);
if (converter != null) {
return converter;
}
}
}
// lets try classes derived from this toType
if (fromType != null) {
Set<Map.Entry<TypeMapping, TypeConverter>> entries = typeMappings.entrySet();
for (Map.Entry<TypeMapping, TypeConverter> entry : entries) {
TypeMapping key = entry.getKey();
Class aToType = key.getToType();
if (toType.isAssignableFrom(aToType)) {
if (key.getFromType().isAssignableFrom(fromType)) {
return entry.getValue();
}
}
}
}
// TODO look at constructors of toType?
return null;
}
/**
* Checks if the registry is loaded and if not lazily load it
*/
protected synchronized void checkLoaded() {
if (!loaded) {
loaded = true;
try {
for (TypeConverterLoader typeConverterLoader : typeConverterLoaders) {
typeConverterLoader.load(this);
}
// lets try load any other fallback converters
try {
loadFallbackTypeConverters();
} catch (NoFactoryAvailableException e) {
// ignore its fine to have none
}
} catch (Exception e) {
throw wrapRuntimeCamelException(e);
}
}
}
protected void loadFallbackTypeConverters() throws IOException, ClassNotFoundException {
FactoryFinder finder = new FactoryFinder();
List<TypeConverter> converters = finder.newInstances("FallbackTypeConverter", getInjector(),
TypeConverter.class);
for (TypeConverter converter : converters) {
addFallbackConverter(converter);
}
}
/**
* Represents a mapping from one type (which can be null) to another
*/
protected static class TypeMapping {
Class toType;
Class fromType;
public TypeMapping(Class toType, Class fromType) {
this.toType = toType;
this.fromType = fromType;
}
public Class getFromType() {
return fromType;
}
public Class getToType() {
return toType;
}
@Override
public boolean equals(Object object) {
if (object instanceof TypeMapping) {
TypeMapping that = (TypeMapping)object;
return ObjectHelper.equal(this.fromType, that.fromType)
&& ObjectHelper.equal(this.toType, that.toType);
}
return false;
}
@Override
public int hashCode() {
int answer = toType.hashCode();
if (fromType != null) {
answer *= 37 + fromType.hashCode();
}
return answer;
}
@Override
public String toString() {
return "[" + fromType + "=>" + toType + "]";
}
}
}