| /* |
| * Copyright (C) 2009 The Android Open Source Project |
| * |
| * 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 android.content; |
| |
| import android.database.Cursor; |
| import android.os.RemoteException; |
| |
| /** |
| * Abstract implementation of EntityIterator that makes it easy to wrap a cursor |
| * that can contain several consecutive rows for an entity. |
| * @hide |
| */ |
| public abstract class CursorEntityIterator implements EntityIterator { |
| private final Cursor mCursor; |
| private boolean mIsClosed; |
| |
| /** |
| * Constructor that makes initializes the cursor such that the iterator points to the |
| * first Entity, if there are any. |
| * @param cursor the cursor that contains the rows that make up the entities |
| */ |
| public CursorEntityIterator(Cursor cursor) { |
| mIsClosed = false; |
| mCursor = cursor; |
| mCursor.moveToFirst(); |
| } |
| |
| /** |
| * Returns the entity that the cursor is currently pointing to. This must take care to advance |
| * the cursor past this entity. This will never be called if the cursor is at the end. |
| * @param cursor the cursor that contains the entity rows |
| * @return the entity that the cursor is currently pointing to |
| * @throws RemoteException if a RemoteException is caught while attempting to build the Entity |
| */ |
| public abstract Entity getEntityAndIncrementCursor(Cursor cursor) throws RemoteException; |
| |
| /** |
| * Returns whether there are more elements to iterate, i.e. whether the |
| * iterator is positioned in front of an element. |
| * |
| * @return {@code true} if there are more elements, {@code false} otherwise. |
| * @see EntityIterator#next() |
| */ |
| public final boolean hasNext() { |
| if (mIsClosed) { |
| throw new IllegalStateException("calling hasNext() when the iterator is closed"); |
| } |
| |
| return !mCursor.isAfterLast(); |
| } |
| |
| /** |
| * Returns the next object in the iteration, i.e. returns the element in |
| * front of the iterator and advances the iterator by one position. |
| * |
| * @return the next object. |
| * @throws java.util.NoSuchElementException |
| * if there are no more elements. |
| * @see EntityIterator#hasNext() |
| */ |
| public Entity next() { |
| if (mIsClosed) { |
| throw new IllegalStateException("calling next() when the iterator is closed"); |
| } |
| if (!hasNext()) { |
| throw new IllegalStateException("you may only call next() if hasNext() is true"); |
| } |
| |
| try { |
| return getEntityAndIncrementCursor(mCursor); |
| } catch (RemoteException e) { |
| throw new RuntimeException("caught a remote exception, this process will die soon", e); |
| } |
| } |
| |
| public void remove() { |
| throw new UnsupportedOperationException("remove not supported by EntityIterators"); |
| } |
| |
| public final void reset() { |
| if (mIsClosed) { |
| throw new IllegalStateException("calling reset() when the iterator is closed"); |
| } |
| mCursor.moveToFirst(); |
| } |
| |
| /** |
| * Indicates that this iterator is no longer needed and that any associated resources |
| * may be released (such as a SQLite cursor). |
| */ |
| public final void close() { |
| if (mIsClosed) { |
| throw new IllegalStateException("closing when already closed"); |
| } |
| mIsClosed = true; |
| mCursor.close(); |
| } |
| } |