/*
* Copyright (C) 2009 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.ws.frameworks.json.impl;
import org.exoplatform.commons.utils.SecurityHelper;
import org.exoplatform.ws.frameworks.json.JsonGenerator;
import org.exoplatform.ws.frameworks.json.impl.JsonUtils.Types;
import org.exoplatform.ws.frameworks.json.value.JsonValue;
import org.exoplatform.ws.frameworks.json.value.impl.ArrayValue;
import org.exoplatform.ws.frameworks.json.value.impl.BooleanValue;
import org.exoplatform.ws.frameworks.json.value.impl.DoubleValue;
import org.exoplatform.ws.frameworks.json.value.impl.LongValue;
import org.exoplatform.ws.frameworks.json.value.impl.NullValue;
import org.exoplatform.ws.frameworks.json.value.impl.ObjectValue;
import org.exoplatform.ws.frameworks.json.value.impl.StringValue;
import java.io.StringReader;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* @author <a href="mailto:andrew00x@gmail.com">Andrey Parfonov</a>
* @version $Id: JsonGeneratorImpl.java 34417 2009-07-23 14:42:56Z dkatayev $
*/
public class JsonGeneratorImpl implements JsonGenerator
{
static final Collection<String> SKIP_METHODS = new HashSet<String>();
static
{
// Prevent discovering of Java class.
SKIP_METHODS.add("getClass");
// Since we need support for Groovy must skip this.
// All "Groovy Objects" implements interface groovy.lang.GroovyObject
// and has method getMetaClass. Not need to discover it.
SKIP_METHODS.add("getMetaClass");
}
/**
* Create JSON array from specified collection.
*
* @param collection source collection
* @return JSON representation of collection
* @throws JsonException if collection can't be transformed in JSON
* representation
*/
public JsonValue createJsonArray(Collection<?> collection) throws JsonException
{
return createJsonValue(collection);
}
/**
* Create JSON array from specified object. Parameter <code>array</code> must
* be array.
*
* @param array source array
* @return JSON representation of array
* @throws JsonException if array can't be transformed in JSON representation
*/
public JsonValue createJsonArray(Object array) throws JsonException
{
if (array == null)
{
return new NullValue();
}
Types t = JsonUtils.getType(array);
if (t == Types.ARRAY_BOOLEAN || t == Types.ARRAY_BYTE || t == Types.ARRAY_SHORT || t == Types.ARRAY_INT
|| t == Types.ARRAY_LONG || t == Types.ARRAY_FLOAT || t == Types.ARRAY_DOUBLE || t == Types.ARRAY_CHAR
|| t == Types.ARRAY_STRING || t == Types.ARRAY_OBJECT)
{
return createJsonValue(array);
}
else
{
throw new JsonException("Invalid argument, must be array.");
}
}
/**
* Create JSON object from specified map.
*
* @param map source map
* @return JSON representation of map
* @throws JsonException if map can't be transformed in JSON representation
*/
public JsonValue createJsonObjectFromMap(Map<String, ?> map) throws JsonException
{
return createJsonValue(map);
}
/**
* Create JSON object from specified string imply it is JSON object in String
* format.
*
* @param s source string
* @return JSON representation of map
* @throws JsonException if map can't be transformed in JSON representation
*/
public JsonValue createJsonObjectFromString(String s) throws JsonException
{
JsonParserImpl parser = new JsonParserImpl();
JsonDefaultHandler handler = new JsonDefaultHandler();
parser.parse(new StringReader(s), handler);
return handler.getJsonObject();
}
/**
* Create JSON object from specified object. Object must be conform with java
* bean structure.
*
* @param object source object
* @return JSON representation of object
* @throws JsonException if map can't be transformed in JSON representation
*/
public JsonValue createJsonObject(Object object) throws JsonException
{
Class<?> clazz = object.getClass();
Method[] methods = clazz.getMethods();
Set<String> transientFields = getTransientFields(clazz);
JsonValue jsonRootValue = new ObjectValue();
for (Method method : methods)
{
String methodName = method.getName();
/*
* Method must be as follow:
* 1. Name starts from "get" plus at least one character or
* starts from "is" plus one more character and return boolean type;
* 2. Must be without parameters;
* 3. Not be in SKIP_METHODS set.
*/
String key = null;
if (!SKIP_METHODS.contains(methodName) && method.getParameterTypes().length == 0)
{
if (methodName.startsWith("get") && methodName.length() > 3)
{
key = methodName.substring(3);
}
else if (methodName.startsWith("is") && methodName.length() > 2
&& (method.getReturnType() == Boolean.class || method.getReturnType() == boolean.class))
{
key = methodName.substring(2);
}
}
if (key != null)
{
// First letter of key to lower case.
key = (key.length() > 1) ? Character.toLowerCase(key.charAt(0)) + key.substring(1) : key.toLowerCase();
// Check is this field in list of transient field.
if (!transientFields.contains(key))
{
try
{
// Get result of invoke method get...
Object invokeResult = method.invoke(object, new Object[0]);
if (JsonUtils.getType(invokeResult) != null)
{
jsonRootValue.addElement(key, createJsonValue(invokeResult));
}
else
{
jsonRootValue.addElement(key, createJsonObject(invokeResult));
}
}
catch (InvocationTargetException e)
{
throw new JsonException(e.getMessage(), e);
}
catch (IllegalAccessException e)
{
throw new JsonException(e.getMessage(), e);
}
}
}
}
return jsonRootValue;
}
/**
* Create JsonValue corresponding to Java object.
*
* @param object source object.
* @return JsonValue.
* @throws JsonException if any errors occurs.
*/
@SuppressWarnings({"unchecked", "rawtypes"})
private JsonValue createJsonValue(Object object) throws JsonException
{
Types type = JsonUtils.getType(object);
switch (type)
{
case NULL :
return new NullValue();
case BOOLEAN :
return new BooleanValue((Boolean)object);
case BYTE :
return new LongValue((Byte)object);
case SHORT :
return new LongValue((Short)object);
case INT :
return new LongValue((Integer)object);
case LONG :
return new LongValue((Long)object);
case FLOAT :
return new DoubleValue((Float)object);
case DOUBLE :
return new DoubleValue((Double)object);
case CHAR :
return new StringValue(Character.toString((Character)object));
case STRING :
return new StringValue((String)object);
case ENUM :
return new StringValue(((Enum)object).name());
case CLASS :
return new StringValue(((Class)object).getName());
case ARRAY_BOOLEAN : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new BooleanValue(Array.getBoolean(object, i)));
}
return jsonArray;
}
case ARRAY_BYTE : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new LongValue(Array.getByte(object, i)));
}
return jsonArray;
}
case ARRAY_SHORT : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new LongValue(Array.getShort(object, i)));
}
return jsonArray;
}
case ARRAY_INT : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new LongValue(Array.getInt(object, i)));
}
return jsonArray;
}
case ARRAY_LONG : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new LongValue(Array.getLong(object, i)));
}
return jsonArray;
}
case ARRAY_FLOAT : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new DoubleValue(Array.getFloat(object, i)));
}
return jsonArray;
}
case ARRAY_DOUBLE : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new DoubleValue(Array.getDouble(object, i)));
}
return jsonArray;
}
case ARRAY_CHAR : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new StringValue(Character.toString(Array.getChar(object, i))));
}
return jsonArray;
}
case ARRAY_STRING : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
jsonArray.addElement(new StringValue((String)Array.get(object, i)));
}
return jsonArray;
}
case ARRAY_OBJECT : {
JsonValue jsonArray = new ArrayValue();
int length = Array.getLength(object);
for (int i = 0; i < length; i++)
{
Object el = Array.get(object, i);
if (JsonUtils.getType(el) != null)
{
jsonArray.addElement(createJsonValue(el));
}
else
{
jsonArray.addElement(createJsonObject(el));
}
}
return jsonArray;
}
case COLLECTION : {
JsonValue jsonArray = new ArrayValue();
List<Object> list = new ArrayList<Object>((Collection<?>)object);
for (Object o : list)
{
if (JsonUtils.getType(o) != null)
{
jsonArray.addElement(createJsonValue(o));
}
else
{
jsonArray.addElement(createJsonObject(o));
}
}
return jsonArray;
}
case MAP :
JsonValue jsonObject = new ObjectValue();
Map<String, Object> map = new HashMap<String, Object>((Map<String, Object>)object);
Set<String> keys = map.keySet();
for (String k : keys)
{
Object o = map.get(k);
if (JsonUtils.getType(o) != null)
{
jsonObject.addElement(k, createJsonValue(o));
}
else
{
jsonObject.addElement(k, createJsonObject(o));
}
}
return jsonObject;
default :
// Must not be here!
return null;
}
}
/**
* Check fields in class which marked as 'transient'. Transient fields will
* be not serialized in JSON representation.
*
* @param clazz the class.
* @return set of fields which must be skiped.
*/
private static Set<String> getTransientFields(final Class<?> clazz)
{
Set<String> set = new HashSet<String>();
Field[] fields = SecurityHelper.doPrivilegedAction(new PrivilegedAction<Field[]>()
{
public Field[] run()
{
return clazz.getDeclaredFields();
}
});
for (Field f : fields)
{
if (Modifier.isTransient(f.getModifiers()))
{
set.add(f.getName());
}
}
return set;
}
}