001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.kahadb.index;
018
019 import java.io.DataInput;
020 import java.io.DataOutput;
021 import java.io.IOException;
022 import java.io.PrintWriter;
023 import java.util.Arrays;
024 import java.util.Iterator;
025 import java.util.Map;
026 import java.util.NoSuchElementException;
027 import java.util.Map.Entry;
028
029 import org.apache.kahadb.index.BTreeIndex.Prefixer;
030 import org.apache.kahadb.page.Page;
031 import org.apache.kahadb.page.Transaction;
032 import org.apache.kahadb.util.VariableMarshaller;
033
034
035 /**
036 * The BTreeNode class represents a node in the BTree object graph. It is stored in
037 * one Page of a PageFile.
038 */
039 public final class BTreeNode<Key,Value> {
040
041 // The index that this node is part of.
042 private final BTreeIndex<Key,Value> index;
043 // The parent node or null if this is the root node of the BTree
044 private BTreeNode<Key,Value> parent;
045 // The page associated with this node
046 private Page<BTreeNode<Key,Value>> page;
047
048 // Order list of keys in the node
049 private Key[] keys;
050 // Values associated with the Keys. Null if this is a branch node.
051 private Value[] values;
052 // nodeId pointers to children BTreeNodes. Null if this is a leaf node.
053 private long[] children;
054 // The next leaf node after this one. Used for fast iteration of the entries.
055 private long next = -1;
056
057 private final class KeyValueEntry implements Map.Entry<Key, Value> {
058 private final Key key;
059 private final Value value;
060
061 public KeyValueEntry(Key key, Value value) {
062 this.key = key;
063 this.value = value;
064 }
065
066 public Key getKey() {
067 return key;
068 }
069
070 public Value getValue() {
071 return value;
072 }
073
074 public Value setValue(Value value) {
075 throw new UnsupportedOperationException();
076 }
077
078 }
079
080 private final class BTreeIterator implements Iterator<Map.Entry<Key, Value>> {
081
082 private final Transaction tx;
083 BTreeNode<Key,Value> current;
084 int nextIndex;
085 Map.Entry<Key,Value> nextEntry;
086
087 private BTreeIterator(Transaction tx, BTreeNode<Key,Value> current, int nextIndex) {
088 this.tx = tx;
089 this.current = current;
090 this.nextIndex=nextIndex;
091 }
092
093 synchronized private void findNextPage() {
094 if( nextEntry!=null ) {
095 return;
096 }
097
098 try {
099 while( current!=null ) {
100 if( nextIndex >= current.keys.length ) {
101 // we need to roll to the next leaf..
102 if( current.next >= 0 ) {
103 current = index.loadNode(tx, current.next, null);
104 assert !current.isBranch() : "Should have linked to the next leaf node.";
105 nextIndex=0;
106 } else {
107 break;
108 }
109 } else {
110 nextEntry = new KeyValueEntry(current.keys[nextIndex], current.values[nextIndex]);
111 nextIndex++;
112 break;
113 }
114
115 }
116 } catch (IOException e) {
117 }
118 }
119
120 public boolean hasNext() {
121 findNextPage();
122 return nextEntry !=null;
123 }
124
125 public Entry<Key, Value> next() {
126 findNextPage();
127 if( nextEntry !=null ) {
128 Entry<Key, Value> lastEntry = nextEntry;
129 nextEntry=null;
130 return lastEntry;
131 } else {
132 throw new NoSuchElementException();
133 }
134 }
135
136 public void remove() {
137 throw new UnsupportedOperationException();
138 }
139 }
140
141 /**
142 * The Marshaller is used to store and load the data in the BTreeNode into a Page.
143 *
144 * @param <Key>
145 * @param <Value>
146 */
147 static public class Marshaller<Key,Value> extends VariableMarshaller<BTreeNode<Key,Value>> {
148 private final BTreeIndex<Key,Value> index;
149
150 public Marshaller(BTreeIndex<Key,Value> index) {
151 this.index = index;
152 }
153
154 public void writePayload(BTreeNode<Key,Value> node, DataOutput os) throws IOException {
155 // Write the keys
156 short count = (short)node.keys.length; // cast may truncate value...
157 if( count != node.keys.length ) {
158 throw new IOException("Too many keys");
159 }
160
161 os.writeShort(count);
162 for (int i = 0; i < node.keys.length; i++) {
163 index.getKeyMarshaller().writePayload(node.keys[i], os);
164 }
165
166 if( node.isBranch() ) {
167 // If this is a branch...
168 os.writeBoolean(true);
169 for (int i = 0; i < count+1; i++) {
170 os.writeLong(node.children[i]);
171 }
172
173 } else {
174 // If this is a leaf
175 os.writeBoolean(false);
176 for (int i = 0; i < count; i++) {
177 index.getValueMarshaller().writePayload(node.values[i], os);
178 }
179 os.writeLong(node.next);
180 }
181 }
182
183 @SuppressWarnings("unchecked")
184 public BTreeNode<Key,Value> readPayload(DataInput is) throws IOException {
185 BTreeNode<Key,Value> node = new BTreeNode<Key,Value>(index);
186 int count = is.readShort();
187
188 node.keys = (Key[])new Object[count];
189 for (int i = 0; i < count; i++) {
190 node.keys[i] = index.getKeyMarshaller().readPayload(is);
191 }
192
193 if( is.readBoolean() ) {
194 node.children = new long[count+1];
195 for (int i = 0; i < count+1; i++) {
196 node.children[i] = is.readLong();
197 }
198 } else {
199 node.values = (Value[])new Object[count];
200 for (int i = 0; i < count; i++) {
201 node.values[i] = index.getValueMarshaller().readPayload(is);
202 }
203 node.next = is.readLong();
204 }
205 return node;
206 }
207 }
208
209 public BTreeNode(BTreeIndex<Key,Value> index) {
210 this.index = index;
211 }
212
213 public void setEmpty() {
214 setLeafData(createKeyArray(0), createValueArray(0));
215 }
216
217
218 /**
219 * Internal (to the BTreeNode) method. Because this method is called only by
220 * BTreeNode itself, no synchronization done inside of this method.
221 * @throws IOException
222 */
223 private BTreeNode<Key,Value> getChild(Transaction tx, int idx) throws IOException {
224 if (isBranch() && idx >= 0 && idx < children.length) {
225 BTreeNode<Key, Value> result = this.index.loadNode(tx, children[idx], this);
226 return result;
227 } else {
228 return null;
229 }
230 }
231
232
233 /**
234 * Returns the right most leaf from the current btree graph.
235 * @throws IOException
236 */
237 private BTreeNode<Key,Value> getRightLeaf(Transaction tx) throws IOException {
238 BTreeNode<Key,Value> cur = this;
239 while(cur.isBranch()) {
240 cur = cur.getChild(tx, cur.keys.length);
241 }
242 return cur;
243 }
244
245 /**
246 * Returns the left most leaf from the current btree graph.
247 * @throws IOException
248 */
249 private BTreeNode<Key,Value> getLeftLeaf(Transaction tx) throws IOException {
250 BTreeNode<Key,Value> cur = this;
251 while(cur.isBranch()) {
252 cur = cur.getChild(tx, 0);
253 }
254 return cur;
255 }
256
257 /**
258 * Returns the left most leaf from the current btree graph.
259 * @throws IOException
260 */
261 private BTreeNode<Key,Value> getLeftPeer(Transaction tx, BTreeNode<Key,Value> x) throws IOException {
262 BTreeNode<Key,Value> cur = x;
263 while( cur.parent !=null ) {
264 if( cur.parent.children[0] == cur.getPageId() ) {
265 cur = cur.parent;
266 } else {
267 for( int i=0; i < cur.parent.children.length; i ++) {
268 if( cur.parent.children[i]==cur.getPageId() ) {
269 return cur.parent.getChild(tx, i-1);
270 }
271 }
272 throw new AssertionError("page "+x+" was decendent of "+cur.getPageId());
273 }
274 }
275 return null;
276 }
277
278 public Value remove(Transaction tx, Key key) throws IOException {
279
280 if(isBranch()) {
281 int idx = Arrays.binarySearch(keys, key);
282 idx = idx < 0 ? -(idx + 1) : idx + 1;
283 BTreeNode<Key, Value> child = getChild(tx, idx);
284 if( child.getPageId() == index.getPageId() ) {
285 throw new IOException("BTree corrupted: Cylce detected.");
286 }
287 Value rc = child.remove(tx, key);
288
289 // child node is now empty.. remove it from the branch node.
290 if( child.keys.length == 0 ) {
291
292 // If the child node is a branch, promote
293 if( child.isBranch() ) {
294 // This is cause branches are never really empty.. they just go down to 1 child..
295 children[idx] = child.children[0];
296 } else {
297
298 // The child was a leaf. Then we need to actually remove it from this branch node..
299 // and relink the previous leaf to skip to the next leaf.
300
301 BTreeNode<Key, Value> previousLeaf = null;
302 if( idx > 0 ) {
303 // easy if we this node hold the previous child.
304 previousLeaf = getChild(tx, idx-1).getRightLeaf(tx);
305 } else {
306 // less easy if we need to go to the parent to find the previous child.
307 BTreeNode<Key, Value> lp = getLeftPeer(tx, this);
308 if( lp!=null ) {
309 previousLeaf = lp.getRightLeaf(tx);
310 }
311 // lp will be null if there was no previous child.
312 }
313
314 if( previousLeaf !=null ) {
315 previousLeaf.next = child.next;
316 index.storeNode(tx, previousLeaf, true);
317 }
318
319 if( idx < children.length-1 ) {
320 // Delete it and key to the right.
321 setBranchData(arrayDelete(keys, idx), arrayDelete(children, idx));
322 } else {
323 // It was the last child.. Then delete it and key to the left
324 setBranchData(arrayDelete(keys, idx-1), arrayDelete(children, idx));
325 }
326
327 // If we are the root node, and only have 1 child left. Then
328 // make the root be the leaf node.
329 if( children.length == 1 && parent==null ) {
330 child = getChild(tx, 0);
331 keys = child.keys;
332 children = child.children;
333 values = child.values;
334 // free up the page..
335 tx.free(child.getPage());
336 }
337
338 }
339 index.storeNode(tx, this, true);
340 }
341
342 return rc;
343 } else {
344 int idx = Arrays.binarySearch(keys, key);
345 if (idx < 0) {
346 return null;
347 } else {
348 Value oldValue = values[idx];
349 setLeafData(arrayDelete(keys, idx), arrayDelete(values, idx));
350
351 if( keys.length==0 && parent!=null) {
352 tx.free(getPage());
353 } else {
354 index.storeNode(tx, this, true);
355 }
356
357 return oldValue;
358 }
359 }
360 }
361
362 public Value put(Transaction tx, Key key, Value value) throws IOException {
363 if (key == null) {
364 throw new IllegalArgumentException("Key cannot be null");
365 }
366
367 if( isBranch() ) {
368 return getLeafNode(tx, this, key).put(tx, key, value);
369 } else {
370 int idx = Arrays.binarySearch(keys, key);
371
372 Value oldValue=null;
373 if (idx >= 0) {
374 // Key was found... Overwrite
375 oldValue = values[idx];
376 values[idx] = value;
377 setLeafData(keys, values);
378 } else {
379 // Key was not found, Insert it
380 idx = -(idx + 1);
381 setLeafData(arrayInsert(keys, key, idx), arrayInsert(values, value, idx));
382 }
383
384 try {
385 index.storeNode(tx, this, allowOverflow());
386 } catch ( Transaction.PageOverflowIOException e ) {
387 // If we get an overflow
388 split(tx);
389 }
390
391 return oldValue;
392 }
393 }
394
395 private void promoteValue(Transaction tx, Key key, long nodeId) throws IOException {
396
397 int idx = Arrays.binarySearch(keys, key);
398 idx = idx < 0 ? -(idx + 1) : idx + 1;
399 setBranchData(arrayInsert(keys, key, idx), arrayInsert(children, nodeId, idx + 1));
400
401 try {
402 index.storeNode(tx, this, allowOverflow());
403 } catch ( Transaction.PageOverflowIOException e ) {
404 split(tx);
405 }
406
407 }
408
409 /**
410 * Internal to the BTreeNode method
411 */
412 private void split(Transaction tx) throws IOException {
413 Key[] leftKeys;
414 Key[] rightKeys;
415 Value[] leftValues=null;
416 Value[] rightValues=null;
417 long[] leftChildren=null;
418 long[] rightChildren=null;
419 Key separator;
420
421 int vc = keys.length;
422 int pivot = vc / 2;
423
424 // Split the node into two nodes
425 if( isBranch() ) {
426
427 leftKeys = createKeyArray(pivot);
428 leftChildren = new long[leftKeys.length + 1];
429 rightKeys = createKeyArray(vc - (pivot + 1));
430 rightChildren = new long[rightKeys.length + 1];
431
432 System.arraycopy(keys, 0, leftKeys, 0, leftKeys.length);
433 System.arraycopy(children, 0, leftChildren, 0, leftChildren.length);
434 System.arraycopy(keys, leftKeys.length + 1, rightKeys, 0, rightKeys.length);
435 System.arraycopy(children, leftChildren.length, rightChildren, 0, rightChildren.length);
436
437 // Is it a Simple Prefix BTree??
438 Prefixer<Key> prefixer = index.getPrefixer();
439 if(prefixer!=null) {
440 separator = prefixer.getSimplePrefix(leftKeys[leftKeys.length - 1], rightKeys[0]);
441 } else {
442 separator = keys[leftKeys.length];
443 }
444
445
446 } else {
447
448 leftKeys = createKeyArray(pivot);
449 leftValues = createValueArray(leftKeys.length);
450 rightKeys = createKeyArray(vc - pivot);
451 rightValues = createValueArray(rightKeys.length);
452
453 System.arraycopy(keys, 0, leftKeys, 0, leftKeys.length);
454 System.arraycopy(values, 0, leftValues, 0, leftValues.length);
455 System.arraycopy(keys, leftKeys.length, rightKeys, 0, rightKeys.length);
456 System.arraycopy(values, leftValues.length, rightValues, 0, rightValues.length);
457
458 // separator = getSeparator(leftVals[leftVals.length - 1],
459 // rightVals[0]);
460 separator = rightKeys[0];
461
462 }
463
464 // Promote the pivot to the parent branch
465 if (parent == null) {
466
467 // This can only happen if this is the root
468 BTreeNode<Key,Value> rNode = this.index.createNode(tx, this);
469 BTreeNode<Key,Value> lNode = this.index.createNode(tx, this);
470
471 if( isBranch() ) {
472 rNode.setBranchData(rightKeys, rightChildren);
473 lNode.setBranchData(leftKeys, leftChildren);
474 } else {
475 rNode.setLeafData(rightKeys, rightValues);
476 lNode.setLeafData(leftKeys, leftValues);
477 lNode.setNext(rNode.getPageId());
478 }
479
480 Key[] v = createKeyArray(1);
481 v[0]=separator;
482 setBranchData(v, new long[] { lNode.getPageId(), rNode.getPageId() });
483
484 index.storeNode(tx, this, true);
485 index.storeNode(tx, rNode, true);
486 index.storeNode(tx, lNode, true);
487
488 } else {
489 BTreeNode<Key,Value> rNode = this.index.createNode(tx, parent);
490
491 if( isBranch() ) {
492 setBranchData(leftKeys, leftChildren);
493 rNode.setBranchData(rightKeys, rightChildren);
494 } else {
495 rNode.setNext(next);
496 next = rNode.getPageId();
497 setLeafData(leftKeys, leftValues);
498 rNode.setLeafData(rightKeys, rightValues);
499 }
500
501 index.storeNode(tx, this, true);
502 index.storeNode(tx, rNode, true);
503 parent.promoteValue(tx, separator, rNode.getPageId());
504 }
505 }
506
507 public void printStructure(Transaction tx, PrintWriter out, String prefix) throws IOException {
508 if( prefix.length()>0 && parent == null ) {
509 throw new IllegalStateException("Cycle back to root node detected.");
510 }
511
512 if( isBranch() ) {
513 for(int i=0 ; i < children.length; i++) {
514 BTreeNode<Key, Value> child = getChild(tx, i);
515 if( i == children.length-1) {
516 out.println(prefix+"\\- "+child.getPageId()+(child.isBranch()?" ("+child.children.length+")":""));
517 child.printStructure(tx, out, prefix+" ");
518 } else {
519 out.println(prefix+"|- "+child.getPageId()+(child.isBranch()?" ("+child.children.length+")":"")+" : "+keys[i]);
520 child.printStructure(tx, out, prefix+" ");
521 }
522 }
523 }
524 }
525
526
527 public int getMinLeafDepth(Transaction tx, int depth) throws IOException {
528 depth++;
529 if( isBranch() ) {
530 int min = Integer.MAX_VALUE;
531 for(int i=0 ; i < children.length; i++) {
532 min = Math.min(min, getChild(tx, i).getMinLeafDepth(tx, depth));
533 }
534 return min;
535 } else {
536 // print(depth*2, "- "+page.getPageId());
537 return depth;
538 }
539 }
540
541 public int getMaxLeafDepth(Transaction tx, int depth) throws IOException {
542 depth++;
543 if( isBranch() ) {
544 int v = 0;
545 for(int i=0 ; i < children.length; i++) {
546 v = Math.max(v, getChild(tx, i).getMaxLeafDepth(tx, depth));
547 }
548 depth = v;
549 }
550 return depth;
551 }
552
553 public Value get(Transaction tx, Key key) throws IOException {
554 if (key == null) {
555 throw new IllegalArgumentException("Key cannot be null");
556 }
557 if( isBranch() ) {
558 return getLeafNode(tx, this, key).get(tx, key);
559 } else {
560 int idx = Arrays.binarySearch(keys, key);
561 if (idx < 0) {
562 return null;
563 } else {
564 return values[idx];
565 }
566 }
567 }
568
569 public boolean isEmpty(final Transaction tx) throws IOException {
570 return keys.length==0;
571 }
572
573 public void visit(Transaction tx, BTreeVisitor<Key, Value> visitor) throws IOException {
574 if (visitor == null) {
575 throw new IllegalArgumentException("Visitor cannot be null");
576 }
577 if( isBranch() ) {
578 for(int i=0; i < this.children.length; i++) {
579 Key key1 = null;
580 if( i!=0 ) {
581 key1 = keys[i-1];
582 }
583 Key key2 = null;
584 if( i!=this.children.length-1 ) {
585 key2 = keys[i];
586 }
587 if( visitor.isInterestedInKeysBetween(key1, key2) ) {
588 BTreeNode<Key, Value> child = getChild(tx, i);
589 child.visit(tx, visitor);
590 }
591 }
592 } else {
593 visitor.visit(Arrays.asList(keys), Arrays.asList(values));
594 }
595 }
596
597 public Map.Entry<Key,Value> getFirst(Transaction tx) throws IOException {
598 BTreeNode<Key, Value> node = this;
599 while( node .isBranch() ) {
600 node = node.getChild(tx, 0);
601 }
602 if( node.values.length>0 ) {
603 return new KeyValueEntry(node.keys[0], node.values[0]);
604 } else {
605 return null;
606 }
607 }
608
609 public Map.Entry<Key,Value> getLast(Transaction tx) throws IOException {
610 BTreeNode<Key, Value> node = this;
611 while( node.isBranch() ) {
612 node = node.getChild(tx, node.children.length-1);
613 }
614 if( node.values.length>0 ) {
615 int idx = node.values.length-1;
616 return new KeyValueEntry(node.keys[idx], node.values[idx]);
617 } else {
618 return null;
619 }
620 }
621
622 public BTreeNode<Key,Value> getFirstLeafNode(Transaction tx) throws IOException {
623 BTreeNode<Key, Value> node = this;
624 while( node .isBranch() ) {
625 node = node.getChild(tx, 0);
626 }
627 return node;
628 }
629
630 public Iterator<Map.Entry<Key,Value>> iterator(final Transaction tx, Key startKey) throws IOException {
631 if (startKey == null) {
632 return iterator(tx);
633 }
634 if( isBranch() ) {
635 return getLeafNode(tx, this, startKey).iterator(tx, startKey);
636 } else {
637 int idx = Arrays.binarySearch(keys, startKey);
638 if (idx < 0) {
639 idx = -(idx + 1);
640 }
641 return new BTreeIterator(tx, this, idx);
642 }
643 }
644
645 public Iterator<Map.Entry<Key,Value>> iterator(final Transaction tx) throws IOException {
646 return new BTreeIterator(tx, getFirstLeafNode(tx), 0);
647 }
648
649 public void clear(Transaction tx) throws IOException {
650 if( isBranch() ) {
651 for (int i = 0; i < children.length; i++) {
652 BTreeNode<Key, Value> node = index.loadNode(tx, children[i], this);
653 node.clear(tx);
654 tx.free(node.getPage());
655 }
656 }
657 // Reset the root node to be a leaf.
658 if( parent == null ) {
659 setLeafData(createKeyArray(0), createValueArray(0));
660 next=-1;
661 index.storeNode(tx, this, true);
662 }
663 }
664
665
666 private static <Key,Value> BTreeNode<Key, Value> getLeafNode(Transaction tx, final BTreeNode<Key, Value> node, Key key) throws IOException {
667 BTreeNode<Key, Value> current = node;
668 while( true ) {
669 if( current.isBranch() ) {
670 int idx = Arrays.binarySearch(current.keys, key);
671 idx = idx < 0 ? -(idx + 1) : idx + 1;
672 BTreeNode<Key, Value> child = current.getChild(tx, idx);
673
674 // A little cycle detection for sanity's sake
675 if( child == node ) {
676 throw new IOException("BTree corrupted: Cylce detected.");
677 }
678
679 current = child;
680 } else {
681 break;
682 }
683 }
684 return current;
685 }
686
687 public boolean contains(Transaction tx, Key key) throws IOException {
688 if (key == null) {
689 throw new IllegalArgumentException("Key cannot be null");
690 }
691
692 if( isBranch() ) {
693 return getLeafNode(tx, this, key).contains(tx, key);
694 } else {
695 int idx = Arrays.binarySearch(keys, key);
696 if (idx < 0) {
697 return false;
698 } else {
699 return true;
700 }
701 }
702 }
703
704 ///////////////////////////////////////////////////////////////////
705 // Implementation methods
706 ///////////////////////////////////////////////////////////////////
707
708
709 private boolean allowOverflow() {
710 // Only allow page overflow if there are <= 3 keys in the node. Otherwise a split will occur on overflow
711 return this.keys.length<=3;
712 }
713
714
715 private void setLeafData(Key[] keys, Value[] values) {
716 this.keys = keys;
717 this.values = values;
718 this.children = null;
719 }
720
721 private void setBranchData(Key[] keys, long[] nodeIds) {
722 this.keys = keys;
723 this.children = nodeIds;
724 this.values = null;
725 }
726
727 @SuppressWarnings("unchecked")
728 private Key[] createKeyArray(int size) {
729 return (Key[])new Object[size];
730 }
731
732 @SuppressWarnings("unchecked")
733 private Value[] createValueArray(int size) {
734 return (Value[])new Object[size];
735 }
736
737 @SuppressWarnings("unchecked")
738 static private <T> T[] arrayDelete(T[] vals, int idx) {
739 T[] newVals = (T[])new Object[vals.length - 1];
740 if (idx > 0) {
741 System.arraycopy(vals, 0, newVals, 0, idx);
742 }
743 if (idx < newVals.length) {
744 System.arraycopy(vals, idx + 1, newVals, idx, newVals.length - idx);
745 }
746 return newVals;
747 }
748
749 static private long[] arrayDelete(long[] vals, int idx) {
750 long[] newVals = new long[vals.length - 1];
751 if (idx > 0) {
752 System.arraycopy(vals, 0, newVals, 0, idx);
753 }
754 if (idx < newVals.length) {
755 System.arraycopy(vals, idx + 1, newVals, idx, newVals.length - idx);
756 }
757 return newVals;
758 }
759
760 @SuppressWarnings("unchecked")
761 static private <T> T[] arrayInsert(T[] vals, T val, int idx) {
762 T[] newVals = (T[])new Object[vals.length + 1];
763 if (idx > 0) {
764 System.arraycopy(vals, 0, newVals, 0, idx);
765 }
766 newVals[idx] = val;
767 if (idx < vals.length) {
768 System.arraycopy(vals, idx, newVals, idx + 1, vals.length - idx);
769 }
770 return newVals;
771 }
772
773
774 static private long[] arrayInsert(long[] vals, long val, int idx) {
775
776 long[] newVals = new long[vals.length + 1];
777 if (idx > 0) {
778 System.arraycopy(vals, 0, newVals, 0, idx);
779 }
780 newVals[idx] = val;
781 if (idx < vals.length) {
782 System.arraycopy(vals, idx, newVals, idx + 1, vals.length - idx);
783 }
784 return newVals;
785 }
786
787 ///////////////////////////////////////////////////////////////////
788 // Property Accessors
789 ///////////////////////////////////////////////////////////////////
790 private boolean isBranch() {
791 return children!=null;
792 }
793
794 public long getPageId() {
795 return page.getPageId();
796 }
797
798 public BTreeNode<Key, Value> getParent() {
799 return parent;
800 }
801
802 public void setParent(BTreeNode<Key, Value> parent) {
803 this.parent = parent;
804 }
805
806 public Page<BTreeNode<Key, Value>> getPage() {
807 return page;
808 }
809
810 public void setPage(Page<BTreeNode<Key, Value>> page) {
811 this.page = page;
812 }
813
814 public long getNext() {
815 return next;
816 }
817
818 public void setNext(long next) {
819 this.next = next;
820 }
821
822 @Override
823 public String toString() {
824 return "[BTreeNode "+(isBranch()?"branch":"leaf")+": "+Arrays.asList(keys)+"]";
825 }
826
827 }
828
829