notes-master1/java/net/micode/notes/gtask/data/SqlData.java

/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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 net.micode.notes.gtask.data;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.util.Log;

import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;
import net.micode.notes.gtask.exception.ActionFailureException;

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


public class SqlData {
    private static final String TAG = SqlData.class.getSimpleName();
    private static final int INVALID_ID = -99999; // 无效ID标识

    // 数据库查询投影（指定查询的列）
    public static final String[] PROJECTION_DATA = new String[] {
            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT,
            DataColumns.DATA1, DataColumns.DATA3
    };
    // 投影列的索引常量
    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;

    // 对象属性（对应数据库表字段）
    private ContentResolver mContentResolver;    // 内容解析器
    private boolean mIsCreate;                  // 是否为新建状态
    private long mDataId;                       // 数据ID
    private String mDataMimeType;               // MIME类型
    private String mDataContent;                // 数据内容
    private long mDataContentData1;             // 附加数据1（长整型）
    private String mDataContentData3;           // 附加数据3（字符串）
    private ContentValues mDiffDataValues;      // 记录变更的ContentValues

    // 构造函数：初始化新对象
    public SqlData(Context context) {
        mContentResolver = context.getContentResolver();
        mIsCreate = true;
        mDataId = INVALID_ID;
        mDataMimeType = DataConstants.NOTE;
        mDataContent = "";
        mDataContentData1 = 0;
        mDataContentData3 = "";
        mDiffDataValues = new ContentValues();
    }

    // 从Cursor加载数据的构造函数
    public SqlData(Context context, Cursor c) {
        mContentResolver = context.getContentResolver();
        mIsCreate = false;
        loadFromCursor(c);  // 从游标加载数据
        mDiffDataValues = new ContentValues();
    }

    // 从Cursor加载数据的辅助方法
    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);
    }

    // 根据JSON设置数据内容，并记录变更
    public void setContent(JSONObject js) throws JSONException {
        // 解析ID
        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
        if (mIsCreate || mDataId != dataId) {
            mDiffDataValues.put(DataColumns.ID, dataId);
        }
        mDataId = dataId;

        // 解析MIME类型
        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;

        // 解析内容
        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
        if (mIsCreate || !mDataContent.equals(dataContent)) {
            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
        }
        mDataContent = dataContent;

        // 解析附加数据1
        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
        if (mIsCreate || mDataContentData1 != dataContentData1) {
            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
        }
        mDataContentData1 = dataContentData1;

        // 解析附加数据3
        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
        }
        mDataContentData3 = dataContentData3;
    }

    // 将对象数据转换为JSON
    public JSONObject getContent() throws JSONException {
        if (mIsCreate) {
            Log.e(TAG, "数据未创建到数据库中");
            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;
    }

    // 提交数据到数据库（插入或更新）
    public void commit(long noteId, boolean validateVersion, long version) {
        if (mIsCreate) {
            // 新建数据时移除无效ID，并添加noteId关联
            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
                mDiffDataValues.remove(DataColumns.ID);
            }
            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
            // 插入数据
            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
            try {
                mDataId = Long.parseLong(uri.getPathSegments().get(1));
            } catch (NumberFormatException e) {
                Log.e(TAG, "获取ID失败", e);
                throw new ActionFailureException("创建笔记失败");
            }
        } else {
            // 更新数据时支持版本验证
            if (mDiffDataValues.size() > 0) {
                int result = 0;
                if (!validateVersion) {
                    // 不验证版本时直接更新
                    result = mContentResolver.update(
                            ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, mDataId),
                            mDiffDataValues, null, null);
                } else {
                    // 验证版本时添加条件（防止并发冲突）
                    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, "更新失败，可能同步时用户已修改笔记");
                }
            }
        }
        // 清空变更记录，并标记为非新建状态
        mDiffDataValues.clear();
        mIsCreate = false;
    }

    // 获取数据ID
    public long getId() {
        return mDataId;
    }
}