org.eclipse.jetty.util.ajax.JSONPojoConvertor Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.util.ajax;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import org.eclipse.jetty.util.ajax.JSON.Output;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Converts POJOs to JSON and vice versa.
* The key differences with respect to {@link JSONObjectConvertor} are:
*
* - returns the actual object from Convertor.fromJSON (JSONObjectConverter returns a Map)
* - the getters/setters are resolved at initialization (JSONObjectConverter resolves it at runtime)
* - correctly sets the number fields
*
*/
public class JSONPojoConvertor implements JSON.Convertor
{
private static final Logger LOG = LoggerFactory.getLogger(JSONPojoConvertor.class);
private static final Map, NumberType> __numberTypes = new HashMap<>();
private static final NumberType SHORT = Number::shortValue;
private static final NumberType INTEGER = Number::intValue;
private static final NumberType FLOAT = Number::floatValue;
private static final NumberType LONG = Number::longValue;
private static final NumberType DOUBLE = Number::doubleValue;
static
{
__numberTypes.put(Short.class, SHORT);
__numberTypes.put(Short.TYPE, SHORT);
__numberTypes.put(Integer.class, INTEGER);
__numberTypes.put(Integer.TYPE, INTEGER);
__numberTypes.put(Long.class, LONG);
__numberTypes.put(Long.TYPE, LONG);
__numberTypes.put(Float.class, FLOAT);
__numberTypes.put(Float.TYPE, FLOAT);
__numberTypes.put(Double.class, DOUBLE);
__numberTypes.put(Double.TYPE, DOUBLE);
}
public static NumberType getNumberType(Class clazz)
{
return __numberTypes.get(clazz);
}
protected boolean _fromJSON;
protected Class _pojoClass;
protected Map _getters = new HashMap<>();
protected Map _setters = new HashMap<>();
protected Set _excluded;
/**
* @param pojoClass The class to convert
*/
public JSONPojoConvertor(Class pojoClass)
{
this(pojoClass, null, true);
}
/**
* @param pojoClass The class to convert
* @param fromJSON If true, add a class field to the JSON
*/
public JSONPojoConvertor(Class pojoClass, boolean fromJSON)
{
this(pojoClass, null, fromJSON);
}
/**
* @param pojoClass The class to convert
* @param excluded The fields to exclude
*/
public JSONPojoConvertor(Class pojoClass, String[] excluded)
{
this(pojoClass, new HashSet<>(Arrays.asList(excluded)));
}
/**
* @param pojoClass The class to convert
* @param excluded The fields to exclude
*/
public JSONPojoConvertor(Class pojoClass, Set excluded)
{
this(pojoClass, excluded, true);
}
/**
* @param pojoClass The class to convert
* @param excluded The fields to exclude
* @param fromJSON If true, add a class field to the JSON
*/
public JSONPojoConvertor(Class pojoClass, Set excluded, boolean fromJSON)
{
_pojoClass = pojoClass;
_excluded = excluded;
_fromJSON = fromJSON;
init();
}
protected void init()
{
Method[] methods = _pojoClass.getMethods();
for (Method m : methods)
{
if (!Modifier.isStatic(m.getModifiers()) && m.getDeclaringClass() != Object.class)
{
String name = m.getName();
switch (m.getParameterCount())
{
case 0:
if (m.getReturnType() != null)
{
if (name.startsWith("is") && name.length() > 2)
name = name.substring(2, 3).toLowerCase(Locale.ENGLISH) + name.substring(3);
else if (name.startsWith("get") && name.length() > 3)
name = name.substring(3, 4).toLowerCase(Locale.ENGLISH) + name.substring(4);
else
break;
if (includeField(name, m))
addGetter(name, m);
}
break;
case 1:
if (name.startsWith("set") && name.length() > 3)
{
name = name.substring(3, 4).toLowerCase(Locale.ENGLISH) + name.substring(4);
if (includeField(name, m))
addSetter(name, m);
}
break;
default:
break;
}
}
}
}
protected void addGetter(String name, Method method)
{
_getters.put(name, method);
}
protected void addSetter(String name, Method method)
{
_setters.put(name, new Setter(name, method));
}
protected Setter getSetter(String name)
{
return _setters.get(name);
}
protected boolean includeField(String name, Method m)
{
return _excluded == null || !_excluded.contains(name);
}
@Override
public Object fromJSON(Map object)
{
try
{
Object obj = _pojoClass.getConstructor().newInstance();
setProps(obj, object);
return obj;
}
catch (Exception e)
{
// TODO return Map instead?
throw new RuntimeException(e);
}
}
private void setProps(Object obj, Map props)
{
for (Map.Entry entry : props.entrySet())
{
Setter setter = getSetter(entry.getKey());
if (setter != null)
{
try
{
setter.invoke(obj, entry.getValue());
}
catch (Exception e)
{
// TODO throw exception?
LOG.warn("{}#{} not set from value {}={}: {}",
_pojoClass.getName(),
setter.getPropertyName(),
setter.getType().getName(),
entry.getValue(),
e.toString());
}
}
}
}
@Override
public void toJSON(Object obj, Output out)
{
if (_fromJSON)
out.addClass(_pojoClass);
for (Map.Entry entry : _getters.entrySet())
{
try
{
out.add(entry.getKey(), entry.getValue().invoke(obj));
}
catch (Exception e)
{
// TODO throw exception?
LOG.warn("{}#{} excluded: {}",
_pojoClass.getName(),
entry.getKey(),
e.toString());
}
}
}
public static class Setter
{
protected String _propertyName;
protected Method _setter;
protected NumberType _numberType;
protected Class _type;
protected Class _componentType;
public Setter(String propertyName, Method method)
{
_propertyName = propertyName;
_setter = method;
_type = method.getParameterTypes()[0];
_numberType = JSONPojoConvertor.getNumberType(_type);
if (_numberType == null && _type.isArray())
{
_componentType = _type.getComponentType();
_numberType = JSONPojoConvertor.getNumberType(_componentType);
}
}
public String getPropertyName()
{
return _propertyName;
}
public Method getMethod()
{
return _setter;
}
public NumberType getNumberType()
{
return _numberType;
}
public Class getType()
{
return _type;
}
public Class getComponentType()
{
return _componentType;
}
public boolean isPropertyNumber()
{
return getNumberType() != null;
}
public void invoke(Object obj, Object value) throws Exception
{
if (value == null)
_setter.invoke(obj, value);
else
invokeObject(obj, value);
}
protected void invokeObject(Object obj, Object value) throws Exception
{
if (_type.isEnum())
{
if (value instanceof Enum)
{
_setter.invoke(obj, value);
}
else
{
@SuppressWarnings({"rawtypes", "unchecked"})
Class enumType = (Class)_type;
@SuppressWarnings("unchecked")
Enum enumValue = Enum.valueOf(enumType, value.toString());
_setter.invoke(obj, enumValue);
}
}
else if (isPropertyNumber() && value instanceof Number)
{
_setter.invoke(obj, _numberType.getActualValue((Number)value));
}
else if (Character.TYPE.equals(_type) || Character.class.equals(_type))
{
_setter.invoke(obj, String.valueOf(value).charAt(0));
}
else if (_componentType != null && value.getClass().isArray())
{
if (_numberType == null)
{
int len = Array.getLength(value);
Object array = Array.newInstance(getComponentType(), len);
try
{
System.arraycopy(value, 0, array, 0, len);
_setter.invoke(obj, array);
}
catch (Exception e)
{
// Unusual array with multiple types.
LOG.trace("IGNORED", e);
_setter.invoke(obj, value);
}
}
else
{
Object[] old = (Object[])value;
Object array = Array.newInstance(getComponentType(), old.length);
try
{
for (int i = 0; i < old.length; i++)
{
Array.set(array, i, _numberType.getActualValue((Number)old[i]));
}
_setter.invoke(obj, array);
}
catch (Exception e)
{
// unusual array with multiple types
LOG.trace("IGNORED", e);
_setter.invoke(obj, value);
}
}
}
else
{
_setter.invoke(obj, value);
}
}
}
public interface NumberType
{
public Object getActualValue(Number number);
}
}
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