Android Open Source - spades Query

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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  w w  .j  a v  a  2 s .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.query;

import static android.text.TextUtils.join;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import cat.picas.spades.Column;
import cat.picas.spades.CursorInfo;
import cat.picas.spades.CursorInfoBuilder;
import cat.picas.spades.SqlHelper;
import cat.picas.spades.Table;

public class Query {

  private NameMapper mMapper = new NameMapper();
  private ColumnSelector mSelector = new ColumnSelector();
  private ArrayList<String> mFromClauses = new ArrayList<String>();
  private ArrayList<String> mWhereClauses = new ArrayList<String>();
  private ArrayList<String> mWhereArgs = new ArrayList<String>();
  private ArrayList<String> mOrderBy = new ArrayList<String>();
  private ArrayList<String> mGroupByClauses = new ArrayList<String>();
  private String mLimit;
  private boolean mDistinct;

  public Query(Table fromTable) {
    mSelector.setAutoEntitiesId(true);
    mSelector.setAutoRowsId(true);
    from(fromTable);
  }

  public Query select(Table table) {
    for (Column column : table.getColumns()) {
      mSelector.selectColumn(column);
    }
    return this;
  }

  public Query select(Column... cols) {
    for (Column column : cols) {
      mSelector.selectColumn(column);
    }
    return this;
  }

  public Query select(String expr, Column... cols) {
    mSelector.selectColumn(expr, cols);
    return this;
  }

  public Query from(Table table) {
    if (mSelector.hasTables()) {
      throw new IllegalArgumentException("From clause already defined");
    }
    mSelector.addTable(table);
    mFromClauses.add(table.name + " AS " + mMapper.alias(table));
    return this;
  }

  public Query leftJoin(Table table, String onExpr, Column... onExprCols) {
    customJoin("LEFT", table, onExpr, onExprCols);
    return this;
  }

  public Query innerJoin(Table table, String onExpr, Column... onExprCols) {
    customJoin("INNER", table, onExpr, onExprCols);
    return this;
  }

  public Query where(Column col, String expr) {
    mWhereClauses.add(SqlHelper.expr("%s " + expr, col));
    return this;
  }

  public Query where(String expr, Column... cols) {
    mWhereClauses.add(SqlHelper.expr(expr, cols));
    return this;
  }

  public Query params(String... params) {
    mWhereArgs.addAll(Arrays.asList(params));
    return this;
  }

  public Query groupBy(Column... cols) {
    for (Column col : cols) {
      mGroupByClauses.add(mMapper.ref(col));
    }
    return this;
  }

  public Query groupBy(String expr, Column... cols) {
    mGroupByClauses.add(SqlHelper.expr(expr, cols));
    return this;
  }

  public Query orderBy(Column col, boolean asc) {
    mOrderBy.add(mMapper.ref(col) + " " + (asc ? "ASC" : "DESC"));
    return this;
  }

  public Query limit(int limit) {
    return limit(limit, 0);
  }

  public Query limit(int limit, int offset) {
    if (limit == 0) {
      mLimit = null;
    } else {
      mLimit = (offset > 0 ? limit + " OFFSET " + offset : String.valueOf(limit));
    }
    return this;
  }

  public Query distinct() {
    mDistinct = true;
    return this;
  }

  public Query setDistinct(boolean state) {
    mDistinct = state;
    return this;
  }

  public Query setAutoEntitiesId(boolean state) {
    mSelector.setAutoEntitiesId(state);
    return this;
  }

  public Query setAutoRowsId(boolean state) {
    mSelector.setAutoRowsId(state);
    return this;
  }

  public boolean isDistinct() {
    return mDistinct;
  }

  public boolean hasAutoEntitiesId() {
    return mSelector.isAutoEntitiesId();
  }

  public boolean hasAutoRowsId() {
    return mSelector.isAutoRowsId();
  }

  public boolean hasTable(Table table) {
    return mSelector.hasTable(table);
  }

  public CursorInfo getCursorInfo() {
    CursorInfoBuilder builder = new CursorInfoBuilder();
    for (SelectedColumn selected : mSelector.getSelectedColumns()) {
      if (!selected.isCustom()) {
        builder.add(selected.getColumn());
      } else {
        builder.addOffset();
      }
    }
    return builder.build();
  }

  public Cursor execute(SQLiteDatabase db) {
    checkFromClause();

    String tables= join(" ", mFromClauses);
    String[] columns = prepareColumnsStrings(false);
    String selection = mWhereClauses.isEmpty() ? null : join(" AND ", mWhereClauses);
    String[] selectionArgs = mWhereArgs.isEmpty() ? null
        : (String[]) mWhereArgs.toArray(new String[mWhereArgs.size()]);
    String groupBy = mGroupByClauses.isEmpty() ? null : join(",", mGroupByClauses);
    String orderBy = mOrderBy.isEmpty() ? null : join(",", mOrderBy);

    return db.query(mDistinct, tables, columns, selection, selectionArgs, groupBy, null, orderBy, mLimit);
  }

  public int count(SQLiteDatabase db) {
    checkFromClause();

    String tables= join(" ", mFromClauses);
    String[] columns = prepareColumnsStrings(true);
    String selection = mWhereClauses.isEmpty() ? null : join(" AND ", mWhereClauses);
    String[] selectionArgs = mWhereArgs.isEmpty() ? null
        : (String[]) mWhereArgs.toArray(new String[mWhereArgs.size()]);
    String groupBy = mGroupByClauses.isEmpty() ? null : join(",", mGroupByClauses);

    int res = 0;
    Cursor cursor = db.query(tables, columns, selection, selectionArgs, groupBy, null, null);
    if (cursor.moveToFirst()) {
      res = cursor.getInt(0);
    }
    cursor.close();

    return res;
  }

  protected void customJoin(String type, Table table, String onExpr, Column... onExprCols) {
    checkFromClause();
    mSelector.addTable(table);
    mFromClauses.add(type + " JOIN " + table.name + " AS " + mMapper.alias(table) + " ON "
        + SqlHelper.expr(onExpr, onExprCols));
  }

  protected void checkFromClause() {
    if (!mSelector.hasTables()) {
      throw new IllegalArgumentException("Missing from clause");
    }
  }

  protected String[] prepareColumnsStrings(boolean forCount) {
    List<SelectedColumn> selectedCols;
    if (forCount) {
      selectedCols = mSelector.getSelectedColumnsForCount();
    } else {
      selectedCols = mSelector.getSelectedColumns();
    }
    int i = 0;
    String[] columns = new String[selectedCols.size()];
    for (SelectedColumn selected : selectedCols) {
      columns[i++] = selected.format();
    }
    return columns;
  }

}

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