17dd252788645e940eada959bdde927426e2531c9Paul Duffin/* 27dd252788645e940eada959bdde927426e2531c9Paul Duffin * Copyright (C) 2012 The Guava Authors 37dd252788645e940eada959bdde927426e2531c9Paul Duffin * 47dd252788645e940eada959bdde927426e2531c9Paul Duffin * Licensed under the Apache License, Version 2.0 (the "License"); 57dd252788645e940eada959bdde927426e2531c9Paul Duffin * you may not use this file except in compliance with the License. 67dd252788645e940eada959bdde927426e2531c9Paul Duffin * You may obtain a copy of the License at 77dd252788645e940eada959bdde927426e2531c9Paul Duffin * 87dd252788645e940eada959bdde927426e2531c9Paul Duffin * http://www.apache.org/licenses/LICENSE-2.0 97dd252788645e940eada959bdde927426e2531c9Paul Duffin * 107dd252788645e940eada959bdde927426e2531c9Paul Duffin * Unless required by applicable law or agreed to in writing, software 117dd252788645e940eada959bdde927426e2531c9Paul Duffin * distributed under the License is distributed on an "AS IS" BASIS, 127dd252788645e940eada959bdde927426e2531c9Paul Duffin * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 137dd252788645e940eada959bdde927426e2531c9Paul Duffin * See the License for the specific language governing permissions and 147dd252788645e940eada959bdde927426e2531c9Paul Duffin * limitations under the License. 157dd252788645e940eada959bdde927426e2531c9Paul Duffin */ 167dd252788645e940eada959bdde927426e2531c9Paul Duffin 177dd252788645e940eada959bdde927426e2531c9Paul Duffinpackage com.google.common.collect; 187dd252788645e940eada959bdde927426e2531c9Paul Duffin 197dd252788645e940eada959bdde927426e2531c9Paul Duffinimport static com.google.common.base.Preconditions.checkNotNull; 207dd252788645e940eada959bdde927426e2531c9Paul Duffin 217dd252788645e940eada959bdde927426e2531c9Paul Duffinimport com.google.common.annotations.GwtCompatible; 227dd252788645e940eada959bdde927426e2531c9Paul Duffin 237dd252788645e940eada959bdde927426e2531c9Paul Duffinimport java.util.Iterator; 247dd252788645e940eada959bdde927426e2531c9Paul Duffin 257dd252788645e940eada959bdde927426e2531c9Paul Duffin/** 267dd252788645e940eada959bdde927426e2531c9Paul Duffin * An iterator that transforms a backing iterator; for internal use. This avoids 277dd252788645e940eada959bdde927426e2531c9Paul Duffin * the object overhead of constructing a {@link Function} for internal methods. 287dd252788645e940eada959bdde927426e2531c9Paul Duffin * 297dd252788645e940eada959bdde927426e2531c9Paul Duffin * @author Louis Wasserman 307dd252788645e940eada959bdde927426e2531c9Paul Duffin */ 317dd252788645e940eada959bdde927426e2531c9Paul Duffin@GwtCompatible 327dd252788645e940eada959bdde927426e2531c9Paul Duffinabstract class TransformedIterator<F, T> implements Iterator<T> { 337dd252788645e940eada959bdde927426e2531c9Paul Duffin final Iterator<? extends F> backingIterator; 347dd252788645e940eada959bdde927426e2531c9Paul Duffin 357dd252788645e940eada959bdde927426e2531c9Paul Duffin TransformedIterator(Iterator<? extends F> backingIterator) { 367dd252788645e940eada959bdde927426e2531c9Paul Duffin this.backingIterator = checkNotNull(backingIterator); 377dd252788645e940eada959bdde927426e2531c9Paul Duffin } 387dd252788645e940eada959bdde927426e2531c9Paul Duffin 397dd252788645e940eada959bdde927426e2531c9Paul Duffin abstract T transform(F from); 407dd252788645e940eada959bdde927426e2531c9Paul Duffin 410888a09821a98ac0680fad765217302858e70fa4Paul Duffin @Override 427dd252788645e940eada959bdde927426e2531c9Paul Duffin public final boolean hasNext() { 437dd252788645e940eada959bdde927426e2531c9Paul Duffin return backingIterator.hasNext(); 447dd252788645e940eada959bdde927426e2531c9Paul Duffin } 457dd252788645e940eada959bdde927426e2531c9Paul Duffin 460888a09821a98ac0680fad765217302858e70fa4Paul Duffin @Override 477dd252788645e940eada959bdde927426e2531c9Paul Duffin public final T next() { 487dd252788645e940eada959bdde927426e2531c9Paul Duffin return transform(backingIterator.next()); 497dd252788645e940eada959bdde927426e2531c9Paul Duffin } 507dd252788645e940eada959bdde927426e2531c9Paul Duffin 510888a09821a98ac0680fad765217302858e70fa4Paul Duffin @Override 527dd252788645e940eada959bdde927426e2531c9Paul Duffin public final void remove() { 537dd252788645e940eada959bdde927426e2531c9Paul Duffin backingIterator.remove(); 547dd252788645e940eada959bdde927426e2531c9Paul Duffin } 557dd252788645e940eada959bdde927426e2531c9Paul Duffin} 56