Android Open Source - RZAndroidBaseUtils Cursor Iterator

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License

The source code is released under:

MIT License

Java Source Code

package com.raizlabs.database;
/*from w  w w. jav a 2 s .c  o  m*/
import java.io.Closeable;
import java.io.IOException;
import java.util.Iterator;

import android.database.Cursor;

/**
 * {@link Iterator} implementation which iterates over the items in a {@link Cursor}.
 * 
 * @author Dylan James
 *
 * @param <T> The type of object stored in the {@link Cursor}.
 */
public abstract class CursorIterator<T> implements Iterator<T>, Closeable {

  private Cursor mCursor;

  /**
   * Creates a {@link CursorIterator} that iterates over the rows of the given
   * {@link Cursor}.
   * @param cursor The {@link Cursor} to iterate over.
   */
  public CursorIterator(Cursor cursor) {
    this.mCursor = cursor;
  }
  
  public void close() throws IOException {
    if (mCursor != null) { 
      mCursor.close();
      mCursor = null;
    }
  }

  @Override
  public boolean hasNext() {
    if (mCursor == null) {
      throw new IllegalStateException("Cannot use a CursorIteator after close() has been called or with a null cursor!");
    }
    return mCursor.getPosition() < mCursor.getCount() - 1;
  }

  @Override
  public T next() {
    if (mCursor == null) {
      throw new IllegalStateException("Cannot use an CursorIterator after close() has been called or with a null cursor!");
    }
    if (mCursor.moveToNext()) {
      return getCurrentItem(mCursor);
    } else {
      return null;
    }
  }

  /**
   * Gets the item at the current row in the cursor. Implementation should only
   * read the current columns, and should be sure not to move the cursor to the
   * next row, as this will cause items to be skipped.
   * @param cursor The {@link Cursor} to read values from.
   * @return The object at the current row in the cursor.
   */
  protected abstract T getCurrentItem(Cursor cursor);

  @Override
  public void remove() {
    throw new UnsupportedOperationException("CursorIterators cannot remove items by default.");
  }

}

Java Source Code List

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