123xiaomi/SqlData.java

import net.micode.notes.gtask.exception.ActionFailureException;

import org.json.JSONException;
import org.json.JSONObject;

/**
 * SqlData类用于处理与数据库相关的操作，主要负责将JSON数据与数据库记录进行相互转换和更新
 */
public class SqlData {
    // 日志标签，用于标识日志来源
    private static final String TAG = SqlData.class.getSimpleName();
    
    // 无效的ID标识，用于表示未初始化或无效的数据库ID
    private static final int INVALID_ID = -99999;
    
    // 数据库查询投影，定义了需要查询的列
    public static final String[] PROJECTION_DATA = new String[] {
            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
            DataColumns.DATA3
    };
    
    // 下面是数据库查询结果中各列的索引位置
    public static final int DATA_ID_COLUMN = 0;
    public static final int DATA_MIME_TYPE_COLUMN = 1;
    public static final int DATA_CONTENT_COLUMN = 2;
    public static final int DATA_CONTENT_DATA_1_COLUMN = 3;
    public static final int DATA_CONTENT_DATA_3_COLUMN = 4;
    
    // ContentResolver用于访问内容提供者
    private ContentResolver mContentResolver;
    
    // 标识当前对象是否是新创建的
    private boolean mIsCreate;
    
    // 下面是数据库记录的各项字段
    private long mDataId;
    private String mDataMimeType;
    private String mDataContent;
    private long mDataContentData1;
    private String mDataContentData3;
    
    // 用于存储待更新的数据库记录值
    private ContentValues mDiffDataValues;
    
    /**
     * 构造函数，用于创建新的SqlData对象
     * @param context 上下文环境，用于获取ContentResolver
     */
    public SqlData(Context context) {
        mContentResolver = context.getContentResolver();
        mIsCreate = true;
        mDataId = INVALID_ID;
        mDataMimeType = DataConstants.NOTE;
        mDataContent = "";
        mDataContentData1 = 0;
        mDataContentData3 = "";
        mDiffDataValues = new ContentValues();
    }
    
    /**
     * 构造函数，用于从现有的数据库记录创建SqlData对象
     * @param context 上下文环境，用于获取ContentResolver
     * @param c 游标对象，指向数据库记录
     */
    public SqlData(Context context, Cursor c) {
        mContentResolver = context.getContentResolver();
        mIsCreate = false;
        loadFromCursor(c);
        mDiffDataValues = new ContentValues();
    }
    
    /**
     * 从游标中加载数据库记录
     * @param c 游标对象，指向数据库记录
     */
    private void loadFromCursor(Cursor c) {
        mDataId = c.getLong(DATA_ID_COLUMN);
        mDataMimeType = c.getString(DATA_MIME_TYPE_COLUMN);
        mDataContent = c.getString(DATA_CONTENT_COLUMN);
        mDataContentData1 = c.getLong(DATA_CONTENT_DATA_1_COLUMN);
        mDataContentData3 = c.getString(DATA_CONTENT_DATA_3_COLUMN);
    }
    
    /**
     * 设置内容，从JSONObject中提取数据并更新到SqlData对象
     * @param js 包含数据的JSONObject对象
     * @throws JSONException 当JSON操作失败时抛出
     */
    public void setContent(JSONObject js) throws JSONException {
        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
        if (mIsCreate || mDataId != dataId) {
            mDiffDataValues.put(DataColumns.ID, dataId);
        }
        mDataId = dataId;
        
        String dataMimeType = js.has(DataColumns.MIME_TYPE) ? js.getString(DataColumns.MIME_TYPE)
                : DataConstants.NOTE;
        if (mIsCreate || !mDataMimeType.equals(dataMimeType)) {
            mDiffDataValues.put(DataColumns.MIME_TYPE, dataMimeType);
        }
        mDataMimeType = dataMimeType;
        
        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
        if (mIsCreate || !mDataContent.equals(dataContent)) {
            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
        }
        mDataContent = dataContent;
        
        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
        if (mIsCreate || mDataContentData1 != dataContentData1) {
            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
        }
        mDataContentData1 = dataContentData1;
        
        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
        }
        mDataContentData3 = dataContentData3;
    }
    
    /**
     * 获取内容，将SqlData对象的数据封装到JSONObject中
     * @return 包含数据的JSONObject对象
     * @throws JSONException 当JSON操作失败时抛出
     */
    public JSONObject getContent() throws JSONException {
        if (mIsCreate) {
            Log.e(TAG, "it seems that we haven't created this in database yet");
            return null;
        }
        JSONObject js = new JSONObject();
        js.put(DataColumns.ID, mDataId);
        js.put(DataColumns.MIME_TYPE, mDataMimeType);
        js.put(DataColumns.CONTENT, mDataContent);
        js.put(DataColumns.DATA1, mDataContentData1);
        js.put(DataColumns.DATA3, mDataContentData3);
        return js;
    }
    
    /**
     * 提交更改，将SqlData对象的数据更新到数据库中
     * @param noteId 笔记的ID
     * @param validateVersion 是否需要验证版本号
     * @param version 版本号
     */
    public void commit(long noteId, boolean validateVersion, long version) {
        if (mIsCreate) {
            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
                mDiffDataValues.remove(DataColumns.ID);
            }
            
            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
            try {
                mDataId = Long.valueOf(uri.getPathSegments().get(1));
            } catch (NumberFormatException e) {
                Log.e(TAG, "Get note id error :" + e.toString());
                throw new ActionFailureException("create note failed");
            }
        } else {
            if (mDiffDataValues.size() > 0) {
                int result = 0;
                if (!validateVersion) {
                    result = mContentResolver.update(ContentUris.withAppendedId(
                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues, null, null);
                } else {
                    result = mContentResolver.update(ContentUris.withAppendedId(
                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues,
                            " ? in (SELECT " + NoteColumns.ID + " FROM " + TABLE.NOTE
                                    + " WHERE " + NoteColumns.VERSION + "=?)", new String[] {
                                    String.valueOf(noteId), String.valueOf(version)
                            });
                }
                if (result == 0) {
                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
                }
            }
        }
        
        mDiffDataValues.clear();
        mIsCreate = false;
    }
    
    /**
     * 获取数据库记录的ID
     * @return 数据库记录的ID
     */
    public long getId() {
        return mDataId;
    }
}