Move CachedIteratorArrayList from core to router

router/java/src/net/i2p/router/transport/udp/PeerState.java

@@ -17,9 +17,9 @@ import net.i2p.data.Hash;
 import net.i2p.data.SessionKey;
 import net.i2p.router.OutNetMessage;
 import net.i2p.router.RouterContext;
+import net.i2p.router.util.CachedIteratorArrayList;
 import net.i2p.router.util.CoDelPriorityBlockingQueue;
 import net.i2p.router.util.PriBlockingQueue;
-import net.i2p.util.CachedIteratorArrayList;
 import net.i2p.util.Log;
 import net.i2p.util.ConcurrentHashSet;
 

router/java/src/net/i2p/router/util/CachedIteratorArrayList.java

@@ -0,0 +1,109 @@
+package net.i2p.router.util;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.ConcurrentModificationException;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+/**
+ * ArrayList that uses a single iterator.  Useful to avoid object churn
+ * while keeping the conveniences of an iterator.
+ * 
+ * @since 0.9.4 moved from net.i2p.util in 0.9.24
+ * 
+ * @author zab
+ */
+public class CachedIteratorArrayList<E> extends ArrayList<E> {
+
+    private static final long serialVersionUID = 4863212596318574111L;
+    
+    private final CachedIterator iterator = new CachedIterator();
+
+    public CachedIteratorArrayList() {
+        super();
+    }
+
+    public CachedIteratorArrayList(Collection<? extends E> c) {
+        super(c);
+    }
+
+    public CachedIteratorArrayList(int initialCapacity) {
+        super(initialCapacity);
+    }
+    
+    @Override
+    public Iterator<E> iterator() {
+        iterator.reset();
+        return iterator;
+    }
+
+    private class CachedIterator implements Iterator<E>, Serializable {
+        /**
+         * Index of element to be returned by subsequent call to next.
+         */
+        int cursor = 0;
+
+        /**
+         * Index of element returned by most recent call to next or
+         * previous.  Reset to -1 if this element is deleted by a call
+         * to remove.
+         */
+        int lastRet = -1;
+
+        /**
+         * The modCount value that the iterator believes that the backing
+         * List should have.  If this expectation is violated, the iterator
+         * has detected concurrent modification.
+         */
+        int expectedModCount = modCount;
+        
+        void reset() {
+            cursor = 0;
+            lastRet = -1;
+            expectedModCount = modCount;
+        }
+
+        public boolean hasNext() {
+            return cursor != size();
+        }
+
+        public E next() {
+            checkForComodification();
+            try {
+                int i = cursor;
+                E next = get(i);
+                lastRet = i;
+                cursor = i + 1;
+                return next;
+            } catch (IndexOutOfBoundsException e) {
+                checkForComodification();
+                throw new NoSuchElementException();
+            }
+        }
+
+        public void remove() {
+            if (lastRet < 0)
+                throw new IllegalStateException();
+            checkForComodification();
+
+            try {
+                CachedIteratorArrayList.this.remove(lastRet);
+                if (lastRet < cursor)
+                    cursor--;
+                lastRet = -1;
+                expectedModCount = modCount;
+            } catch (IndexOutOfBoundsException e) {
+                throw new ConcurrentModificationException();
+            }
+        }
+
+        final void checkForComodification() {
+            if (modCount != expectedModCount)
+                throw new ConcurrentModificationException();
+        }
+
+    }
+    
+}

router/java/test/junit/net/i2p/router/util/CachedIteratorArrayListTest.java

@@ -0,0 +1,92 @@
+package net.i2p.router.util;
+
+import static org.junit.Assert.*;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CachedIteratorArrayListTest {
+
+    private List<Character> l;
+    private Iterator<Character> iter; 
+    
+    @Before
+    public void setUp() {
+        l = new CachedIteratorArrayList<Character>();
+        l.add('a');
+        l.add('b');
+        l.add('c');
+        iter = l.iterator();
+    }
+    
+    /** test iterations work */
+    @Test
+    public void test() {
+        String total = "";
+        
+        // two full for-each iterations
+        for (char i : l)
+            total += i;
+        assertEquals("abc", total);
+        for (char i : l)
+            total += i;
+        assertEquals("abcabc", total);
+        
+        // and one partial
+        total = "";
+        iter = l.iterator();
+        total += iter.next();
+        total += iter.next();
+        iter = l.iterator();
+        total += iter.next();
+        assertEquals("aba",total);
+    }
+    
+    @Test
+    public void testSameness() {
+        Iterator<Character> two = l.iterator();
+        Iterator<Character> one = l.iterator();
+        assertSame(one, two);
+    }
+    
+    @Test
+    public void testRemove() {
+        iter.next();
+        iter.remove();
+
+        // test proper removal
+        assertEquals(2,l.size());
+        assertEquals('b',l.get(0).charValue());
+        assertEquals('c',l.get(1).charValue());
+        
+        // test iterator still workx after removal
+        assertTrue(iter.hasNext());
+        assertEquals('b',iter.next().charValue());
+        assertEquals('c',iter.next().charValue());
+        assertFalse(iter.hasNext());
+    }
+    
+    /** 
+     * tests the Collections.sort method because that is used
+     * in the router and internally creates iterators
+     */
+    @Test
+    public void testSorting() {
+        List<Integer> li = new CachedIteratorArrayList<Integer>();
+        li.add(3);
+        li.add(2);
+        li.add(1);
+        Collections.sort(li);
+        
+        Iterator<Integer> ii = li.iterator();
+        assertEquals(1,ii.next().intValue());
+        assertEquals(2,ii.next().intValue());
+        assertEquals(3,ii.next().intValue());
+        
+        assertFalse(ii.hasNext());
+    }
+}