| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.commons.collections4.iterators; |
| |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.apache.commons.collections4.MapIterator; |
| import org.apache.commons.collections4.ResettableIterator; |
| |
| /** |
| * Implements a {@code MapIterator} using a Map entrySet. |
| * Reverse iteration is not supported. |
| * <pre> |
| * MapIterator it = map.mapIterator(); |
| * while (it.hasNext()) { |
| * Object key = it.next(); |
| * Object value = it.getValue(); |
| * it.setValue(newValue); |
| * } |
| * </pre> |
| * |
| * @param <K> the type of keys |
| * @param <V> the type of mapped values |
| * @since 3.0 |
| */ |
| public class EntrySetMapIterator<K, V> implements MapIterator<K, V>, ResettableIterator<K> { |
| |
| private final Map<K, V> map; |
| private Iterator<Map.Entry<K, V>> iterator; |
| private Map.Entry<K, V> last; |
| private boolean canRemove; |
| |
| /** |
| * Constructor. |
| * |
| * @param map the map to iterate over |
| */ |
| public EntrySetMapIterator(final Map<K, V> map) { |
| this.map = map; |
| this.iterator = map.entrySet().iterator(); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Checks to see if there are more entries still to be iterated. |
| * |
| * @return {@code true} if the iterator has more elements |
| */ |
| @Override |
| public boolean hasNext() { |
| return iterator.hasNext(); |
| } |
| |
| /** |
| * Gets the next <em>key</em> from the {@code Map}. |
| * |
| * @return the next key in the iteration |
| * @throws java.util.NoSuchElementException if the iteration is finished |
| */ |
| @Override |
| public K next() { |
| last = iterator.next(); |
| canRemove = true; |
| return last.getKey(); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Removes the last returned key from the underlying {@code Map}. |
| * <p> |
| * This method can be called once per call to {@code next()}. |
| * |
| * @throws UnsupportedOperationException if remove is not supported by the map |
| * @throws IllegalStateException if {@code next()} has not yet been called |
| * @throws IllegalStateException if {@code remove()} has already been called |
| * since the last call to {@code next()} |
| */ |
| @Override |
| public void remove() { |
| if (canRemove == false) { |
| throw new IllegalStateException("Iterator remove() can only be called once after next()"); |
| } |
| iterator.remove(); |
| last = null; |
| canRemove = false; |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the current key, which is the key returned by the last call |
| * to {@code next()}. |
| * |
| * @return the current key |
| * @throws IllegalStateException if {@code next()} has not yet been called |
| */ |
| @Override |
| public K getKey() { |
| if (last == null) { |
| throw new IllegalStateException("Iterator getKey() can only be called after next() and before remove()"); |
| } |
| return last.getKey(); |
| } |
| |
| /** |
| * Gets the current value, which is the value associated with the last key |
| * returned by {@code next()}. |
| * |
| * @return the current value |
| * @throws IllegalStateException if {@code next()} has not yet been called |
| */ |
| @Override |
| public V getValue() { |
| if (last == null) { |
| throw new IllegalStateException("Iterator getValue() can only be called after next() and before remove()"); |
| } |
| return last.getValue(); |
| } |
| |
| /** |
| * Sets the value associated with the current key. |
| * |
| * @param value the new value |
| * @return the previous value |
| * @throws UnsupportedOperationException if setValue is not supported by the map |
| * @throws IllegalStateException if {@code next()} has not yet been called |
| * @throws IllegalStateException if {@code remove()} has been called since the |
| * last call to {@code next()} |
| */ |
| @Override |
| public V setValue(final V value) { |
| if (last == null) { |
| throw new IllegalStateException("Iterator setValue() can only be called after next() and before remove()"); |
| } |
| return last.setValue(value); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Resets the state of the iterator. |
| */ |
| @Override |
| public void reset() { |
| iterator = map.entrySet().iterator(); |
| last = null; |
| canRemove = false; |
| } |
| |
| /** |
| * Gets the iterator as a String. |
| * |
| * @return a string version of the iterator |
| */ |
| @Override |
| public String toString() { |
| if (last != null) { |
| return "MapIterator[" + getKey() + "=" + getValue() + "]"; |
| } |
| return "MapIterator[]"; |
| } |
| |
| } |