JavaBeanSerializer.java

/*
 * Copyright 1999-2101 Alibaba Group.
 *
 * Licensed 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.zbus.common.json.serializer;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.zbus.common.json.JSON;
import org.zbus.common.json.JSONException;
import org.zbus.common.json.util.FieldInfo;
import org.zbus.common.json.util.TypeUtils;

/**
 * @author wenshao<szujobs@hotmail.com>
 */
public class JavaBeanSerializer implements ObjectSerializer {

    // serializers
    private final FieldSerializer[] getters;
    private final FieldSerializer[] sortedGetters;

    public FieldSerializer[] getGetters() {
        return getters;
    }

    public JavaBeanSerializer(Class<?> clazz){
        this(clazz, (Map<String, String>) null);
    }

    public JavaBeanSerializer(Class<?> clazz, String... aliasList){
        this(clazz, createAliasMap(aliasList));
    }

    static Map<String, String> createAliasMap(String... aliasList) {
        Map<String, String> aliasMap = new HashMap<String, String>();
        for (String alias : aliasList) {
            aliasMap.put(alias, alias);
        }

        return aliasMap;
    }

    public JavaBeanSerializer(Class<?> clazz, Map<String, String> aliasMap){
        {
            List<FieldSerializer> getterList = new ArrayList<FieldSerializer>();
            List<FieldInfo> fieldInfoList = TypeUtils.computeGetters(clazz, aliasMap, false);

            for (FieldInfo fieldInfo : fieldInfoList) {
                getterList.add(createFieldSerializer(fieldInfo));
            }

            getters = getterList.toArray(new FieldSerializer[getterList.size()]);
        }
        {
            List<FieldSerializer> getterList = new ArrayList<FieldSerializer>();
            List<FieldInfo> fieldInfoList = TypeUtils.computeGetters(clazz, aliasMap, true);

            for (FieldInfo fieldInfo : fieldInfoList) {
                getterList.add(createFieldSerializer(fieldInfo));
            }

            sortedGetters = getterList.toArray(new FieldSerializer[getterList.size()]);
        }
    }

    protected boolean isWriteClassName(JSONSerializer serializer, Object obj, Type fieldType, Object fieldName) {
        return serializer.isWriteClassName(fieldType, obj);
    }
    
    public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType) throws IOException {
        SerializeWriter out = serializer.getWriter();

        if (object == null) {
            out.writeNull();
            return;
        }

        if (serializer.containsReference(object)) {
            writeReference(serializer, object);
            return;
        }

        final FieldSerializer[] getters;

        if (out.isEnabled(SerializerFeature.SortField)) {
            getters = this.sortedGetters;
        } else {
            getters = this.getters;
        }

        SerialContext parent = serializer.getContext();
        serializer.setContext(parent, object, fieldName);

        final boolean writeAsArray = serializer.isWriteAsArray(object, fieldType);

        try {
            final char startSeperator = writeAsArray ? '[' : '{';
            final char endSeperator = writeAsArray ? ']' : '}';
            out.append(startSeperator);

            if (getters.length > 0 && out.isEnabled(SerializerFeature.PrettyFormat)) {
                serializer.incrementIndent();
                serializer.println();
            }

            boolean commaFlag = false;

            if (isWriteClassName(serializer, object, fieldType, fieldName)) {
                Class<?> objClass = object.getClass();
                if (objClass != fieldType) {
                    out.writeFieldName(JSON.DEFAULT_TYPE_KEY);
                    serializer.write(object.getClass());
                    commaFlag = true;
                }
            }

            char seperator = commaFlag ? ',' : '\0';

            char newSeperator = FilterUtils.writeBefore(serializer, object, seperator);
            commaFlag = newSeperator == ',';

            for (int i = 0; i < getters.length; ++i) {
                FieldSerializer fieldSerializer = getters[i];

                if (serializer.isEnabled(SerializerFeature.SkipTransientField)) {
                    Field field = fieldSerializer.getField();
                    if (field != null) {
                        if (Modifier.isTransient(field.getModifiers())) {
                            continue;
                        }
                    }
                }

                if (!FilterUtils.applyName(serializer, object, fieldSerializer.getName())) {
                    continue;
                }

                Object propertyValue = fieldSerializer.getPropertyValue(object);

                if (!FilterUtils.apply(serializer, object, fieldSerializer.getName(), propertyValue)) {
                    continue;
                }

                String key = FilterUtils.processKey(serializer, object, fieldSerializer.getName(), propertyValue);

                Object originalValue = propertyValue;
                propertyValue = FilterUtils.processValue(serializer, object, fieldSerializer.getName(), propertyValue);

                if (propertyValue == null && !writeAsArray) {
                    if ((!fieldSerializer.isWriteNull())
                        && (!serializer.isEnabled(SerializerFeature.WriteMapNullValue))) {
                        continue;
                    }
                }

                if (commaFlag) {
                    out.append(',');
                    if (out.isEnabled(SerializerFeature.PrettyFormat)) {
                        serializer.println();
                    }
                }

                if (key != fieldSerializer.getName()) {
                    if (!writeAsArray) {
                        out.writeFieldName(key);
                    }
                    serializer.write(propertyValue);
                } else if (originalValue != propertyValue) {
                    if (!writeAsArray) {
                        fieldSerializer.writePrefix(serializer);
                    }
                    serializer.write(propertyValue);
                } else {
                    if (!writeAsArray) {
                        fieldSerializer.writeProperty(serializer, propertyValue);
                    } else {
                        fieldSerializer.writeValue(serializer, propertyValue);
                    }
                }

                commaFlag = true;
            }
            
            FilterUtils.writeAfter(serializer, object, commaFlag ? ',' : '\0');

            if (getters.length > 0 && out.isEnabled(SerializerFeature.PrettyFormat)) {
                serializer.decrementIdent();
                serializer.println();
            }

            out.append(endSeperator);
        } catch (Exception e) {
            throw new JSONException("write javaBean error", e);
        } finally {
            serializer.setContext(parent);
        }
    }

    public void writeReference(JSONSerializer serializer, Object object) {
        serializer.writeReference(object);
    }

    public FieldSerializer createFieldSerializer(FieldInfo fieldInfo) {
        Class<?> clazz = fieldInfo.getFieldClass();

        if (clazz == Number.class) {
            return new NumberFieldSerializer(fieldInfo);
        }

        return new ObjectFieldSerializer(fieldInfo);
    }
}