package com.firefly.utils.json;
import static com.firefly.utils.json.JsonStringSymbol.ARRAY_PRE;
import static com.firefly.utils.json.JsonStringSymbol.ARRAY_SUF;
import static com.firefly.utils.json.JsonStringSymbol.NULL;
import static com.firefly.utils.json.JsonStringSymbol.OBJ_PRE;
import static com.firefly.utils.json.JsonStringSymbol.OBJ_SEPARATOR;
import static com.firefly.utils.json.JsonStringSymbol.OBJ_SUF;
import static com.firefly.utils.json.JsonStringSymbol.QUOTE;
import static com.firefly.utils.json.JsonStringSymbol.SEPARATOR;
import java.io.IOException;
import java.io.Writer;
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.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import com.firefly.utils.json.support.JsonClassCache;
import com.firefly.utils.json.support.JsonObjMetaInfo;
import com.firefly.utils.json.support.TypeVerify;
import com.firefly.utils.time.SafeSimpleDateFormat;
class JsonSerializer {
private Writer writer;
private Set<Object> existence; // 防止循环引用
private ClassCache classCache;
private static final JsonObjMetaInfo[] JOM = new JsonObjMetaInfo[0];
public JsonSerializer(Writer writer) {
this.writer = writer;
existence = new HashSet<Object>();
classCache = JsonClassCache.getInstance();
}
JsonSerializer toJson(Object obj) throws IOException {
if (obj == null) {
writer.append(NULL);
return this;
}
Class<?> clazz = obj.getClass();
if (TypeVerify.isNumberOrBool(clazz)) { // 数字，布尔类型
writer.append(obj.toString());
} else if (clazz.isEnum()) { // 枚举类型
string2Json(((Enum<?>) obj).name());
} else if (TypeVerify.isString(clazz)) { // 字符串或字符类型
string2Json(obj.toString());
} else if (TypeVerify.isDateLike(clazz)) {
string2Json(SafeSimpleDateFormat.defaultDateFormat
.format((Date) obj));
} else if (existence.contains(obj)) { // 防止循环引用，此处会影响一些性能
writer.append(NULL);
} else {
existence.add(obj);
if (obj instanceof Map<?, ?>) {
map2Json((Map<?, ?>) obj);
} else if (obj instanceof Collection<?>) {
collection2Json((Collection<?>) obj);
} else if (clazz.isArray()) {
array2Json(obj);
} else { // pojo类型
pojo2Json(obj);
}
existence.remove(obj);
}
return this;
}
private void pojo2Json(Object obj) throws IOException {
if (obj == null)
return;
Class<?> clazz = obj.getClass();
writer.append(OBJ_PRE);
JsonObjMetaInfo[] jsonObjMetaInfo = classCache.get(clazz);
if (jsonObjMetaInfo == null) {
List<JsonObjMetaInfo> fieldList = new ArrayList<JsonObjMetaInfo>();
Method[] methods = clazz.getMethods();
for (int i = 0; i < methods.length; i++) {
Method method = methods[i];
method.setAccessible(true);
String methodName = method.getName();
if (Modifier.isStatic(method.getModifiers())
|| method.getReturnType().equals(Void.TYPE)
|| method.getParameterTypes().length != 0) {
continue;
}
if (methodName.startsWith("get")) { // 取get方法的返回值
if (methodName.length() < 4
|| methodName.equals("getClass")
|| !Character.isUpperCase(methodName.charAt(3))) {
continue;
}
String propertyName = Character.toLowerCase(methodName
.charAt(3)) + methodName.substring(4);
Field field = null;
try {
field = clazz.getDeclaredField(propertyName);
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
if (field != null
&& Modifier.isTransient(field.getModifiers())) {
continue;
}
try {
JsonObjMetaInfo fieldSerializer = new JsonObjMetaInfo();
fieldSerializer.setPropertyName(propertyName);
fieldSerializer.setMethod(method);
fieldList.add(fieldSerializer);
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
} else if (methodName.startsWith("is")) { // 取is方法的返回值
if (methodName.length() < 3
|| !Character.isUpperCase(methodName.charAt(2))) {
continue;
}
String propertyName = Character.toLowerCase(methodName
.charAt(2)) + methodName.substring(3);
Field field = null;
try {
field = clazz.getDeclaredField(propertyName);
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
if (field != null
&& Modifier.isTransient(field.getModifiers())) {
continue;
}
try {
JsonObjMetaInfo fieldSerializer = new JsonObjMetaInfo();
fieldSerializer.setPropertyName(propertyName);
fieldSerializer.setMethod(method);
fieldList.add(fieldSerializer);
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
}
}
jsonObjMetaInfo = fieldList.toArray(JOM);
classCache.put(clazz, jsonObjMetaInfo);
}
for (int i = 0; i < jsonObjMetaInfo.length; i++) {
try {
appendPair(jsonObjMetaInfo[i].getPropertyName(),
jsonObjMetaInfo[i].getMethod().invoke(obj));
if (i < jsonObjMetaInfo.length - 1)
writer.append(SEPARATOR);
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
writer.append(OBJ_SUF);
}
@SuppressWarnings("unchecked")
private void map2Json(Map map) throws IOException {
if (map == null)
return;
writer.append(OBJ_PRE);
Set<Entry<?, ?>> entrySet = map.entrySet();
for (Iterator<Entry<?, ?>> it = entrySet.iterator(); it.hasNext();) {
Entry<?, ?> entry = it.next();
String name = entry.getKey() == null ? NULL : entry.getKey()
.toString();
Object val = entry.getValue();
appendPair(name, val);
if (it.hasNext())
writer.append(SEPARATOR);
}
writer.append(OBJ_SUF);
}
private void string2Json(String s) throws IOException {
if (s == null)
writer.append(NULL);
else {
char[] cs = s.toCharArray();
writer.append(QUOTE);
for (char ch : cs) {
switch (ch) {
case '"':
writer.append("\\\"");
break;
case '\b':
writer.append("\\b");
break;
case '\n':
writer.append("\\n");
break;
case '\t':
writer.append("\\t");
break;
case '\f':
writer.append("\\f");
break;
case '\r':
writer.append("\\r");
break;
case '\\':
writer.append("\\\\");
break;
default:
writer.append(ch);
}
}
writer.append(QUOTE);
}
}
private void collection2Json(Collection<?> obj) throws IOException {
writer.append(ARRAY_PRE);
for (Iterator<?> it = obj.iterator(); it.hasNext();) {
toJson(it.next());
if (it.hasNext())
writer.append(SEPARATOR);
}
writer.append(ARRAY_SUF);
}
private void array2Json(Object obj) throws IOException {
writer.append(ARRAY_PRE);
int len = Array.getLength(obj) - 1;
if (len > -1) {
int i;
for (i = 0; i < len; i++) {
toJson(Array.get(obj, i));
writer.append(SEPARATOR);
}
toJson(Array.get(obj, i));
}
writer.append(ARRAY_SUF);
}
private void appendPair(String name, Object val) throws IOException {
string2Json(name);
writer.append(OBJ_SEPARATOR);
toJson(val);
}
@Override
public String toString() {
return writer.toString();
}
}