package com.nhaarman.listviewanimations.itemmanipulation; import android.util.Pair; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Set; import java.util.concurrent.atomic.AtomicInteger; /** * A class to insert items only when there are no active items. * A pending index-item pair can have two states: active and pending. When inserting new items, the {@link com.nhaarman.listviewanimations.itemmanipulation.AnimateAdditionAdapter.Insertable#add * (int, Object)} method will be called directly if there are no active index-item pairs. * Otherwise, pairs will be queued until the active list is empty. */ public class InsertQueue<T> { private final AnimateAdditionAdapter.Insertable<T> mInsertable; private final Set<AtomicInteger> mActiveIndexes = new HashSet<AtomicInteger>(); private final List<Pair<Integer, T>> mPendingItemsToInsert = new ArrayList<Pair<Integer, T>>(); public InsertQueue(final AnimateAdditionAdapter.Insertable<T> insertable) { mInsertable = insertable; } /** * Insert an item into the queue at given index. Will directly call {@link com.nhaarman.listviewanimations.itemmanipulation.AnimateAdditionAdapter.Insertable#add(int, * Object)} if there are no active index-item pairs. Otherwise, the pair will be queued. * @param index the index at which the item should be inserted. * @param item the item to insert. */ public void insert(final int index, final T item) { if (mActiveIndexes.isEmpty() && mPendingItemsToInsert.isEmpty()) { mActiveIndexes.add(new AtomicInteger(index)); //noinspection unchecked mInsertable.add(index, item); } else { mPendingItemsToInsert.add(new Pair<Integer, T>(index, item)); } } @SuppressWarnings("UnusedDeclaration") public void insert(final Pair<Integer, T>... indexItemPair) { insert(Arrays.asList(indexItemPair)); } public void insert(final List<Pair<Integer, T>> indexItemPairs) { if (mActiveIndexes.isEmpty() && mPendingItemsToInsert.isEmpty()) { for (Pair<Integer, T> pair : indexItemPairs) { for (AtomicInteger existing : mActiveIndexes) { if (existing.intValue() >= pair.first) { existing.incrementAndGet(); } } mActiveIndexes.add(new AtomicInteger(pair.first)); mInsertable.add(pair.first, pair.second); } } else { mPendingItemsToInsert.addAll(indexItemPairs); } } /** * Clears the active states and inserts any pending pairs if applicable. */ public void clearActive() { mActiveIndexes.clear(); insertPending(); } /** * Clear the active state for given index. Will insert any pending pairs if this call leads to a state where there are no active pairs. * @param index the index to remove. */ public void removeActiveIndex(final int index) { boolean found = false; for (Iterator<AtomicInteger> iterator = mActiveIndexes.iterator(); iterator.hasNext() && !found; ) { if (iterator.next().get() == index) { iterator.remove(); found = true; } } if (mActiveIndexes.isEmpty()) { insertPending(); } } /** * Inserts pending items into the Insertable, and adds them to the active positions (correctly managing position shifting). Clears the pending items. */ private void insertPending() { for (Pair<Integer, T> pi : mPendingItemsToInsert) { for (AtomicInteger existing : mActiveIndexes) { if (existing.intValue() >= pi.first) { existing.incrementAndGet(); } } mActiveIndexes.add(new AtomicInteger(pi.first)); mInsertable.add(pi.first, pi.second); } mPendingItemsToInsert.clear(); } /** * Returns a collection of currently active indexes. */ public Collection<Integer> getActiveIndexes() { HashSet<Integer> result = new HashSet<Integer>(); for (AtomicInteger i : mActiveIndexes) { result.add(i.get()); } return result; } /** * Returns a {@code List} of {@code Pair}s with the index and items that are pending to be inserted, in the order they were requested. */ public List<Pair<Integer, T>> getPendingItemsToInsert() { return mPendingItemsToInsert; } }