Android Open Source - spades Related Parent

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License

The source code is released under:

Apache License

Java Source Code

/**
 * Copyright (C) 2013 Pau Picas Sans <pau.picas@gmail.com>
 *//from   w ww .  java 2s . c o m
 * 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 cat.picas.spades;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import cat.picas.spades.Column.ColumnId;
import cat.picas.spades.query.Query;

public class RelatedParent<T extends Entity> {

  private ColumnId mParentColumn;
  private Table mParentTable;
  private EntityMapper<T> mParentMapper;
  private String mExtraWhere;

  private boolean mFetched;
  private Long mRawValue;
  private T mParent;

  public RelatedParent(ColumnId parentColumn, EntityMapper<T> parentMapper) {
    mParentColumn = parentColumn;
    mParentTable = mParentColumn.getTable();
    mParentMapper = parentMapper;
  }

  public RelatedParent(ColumnId parentColumn, EntityMapper<T> parentMapper, String extraWhere) {
    this(parentColumn, parentMapper);
    mExtraWhere = extraWhere;
  }

  public boolean isFetched() {
    return mFetched;
  }

  public void reset() {
    mParent = null;
    mFetched = false;
  }

  public T fetch(SQLiteDatabase db) {
    if (!mFetched && mRawValue != null) {
      Query query = createFetchQuery();
      Cursor cursor = query.execute(db);
      if (cursor.moveToFirst()) {
        mParent = mParentMapper.createFromCursor(cursor, query.getCursorInfo());
      } else {
        mParent = null;
      }
      cursor.close();
      mFetched = true;
    }

    return mParent;
  }

  public T fetch(Cursor cursor, CursorInfo cursorInfo) {
    if (!mFetched) {
      // Check if the cursor contains data for this entity.
      if (!cursorInfo.hasTable(mParentTable)) {
        return null;
      }

      // Obtain the cursor index of the related column.
      int parentColIndex = cursorInfo.getColumnIndex(mParentColumn);
      if (parentColIndex != CursorInfo.INVALID_INDEX && !cursor.isNull(parentColIndex)) {
        if (mRawValue != null && !mRawValue.equals(cursor.getLong(parentColIndex))) {
          // Protection against incorrect entity assignments (ID != Foreign key).
          return null;
        } else if (mRawValue == null) {
          // Automatic assignment of raw value.
          mRawValue = cursor.getLong(parentColIndex);
        }
      }

      mParent = mParentMapper.createFromCursor(cursor, cursorInfo);
      mFetched = true;
    }

    return mParent;
  }

  public T get() {
    return mParent;
  }

  public void set(T entity) {
    mParent = entity;
    mRawValue = entity.getEntityId();
    mFetched = true;
  }

  public Long getValue() {
    return mRawValue;
  }

  public void setValue(Long value) {
    reset();
    mRawValue = value;
  }

  public boolean isNull() {
    return mRawValue == null;
  }

  protected Query createFetchQuery() {
    Query query = new Query(mParentTable).where(mParentColumn, "=" + mRawValue).limit(1);
    if (mExtraWhere != null) {
      query.where(mExtraWhere);
    }

    return query;
  }

}

Java Source Code List

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