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better control of failure in node seek of kelondroTree
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git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@2686 6c8d7289-2bf4-0310-a012-ef5d649a1542
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orbiter committed Oct 2, 2006
1 parent ca8ef0c commit b033a80
Showing 1 changed file with 93 additions and 77 deletions.
170 changes: 93 additions & 77 deletions source/de/anomic/kelondro/kelondroTree.java
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Expand Up @@ -270,8 +270,11 @@ public class Search {
private Node thenode, parentnode;
private boolean found; // property if node was found
private byte child; // -1: left child; 0: root node; 1: right child
private Handle thisHandle;

// temporary variables
private Handle thisHandle;
byte[] keybuffer;

protected Search() {
}

Expand All @@ -282,6 +285,8 @@ protected void process(byte[] key) throws IOException {
thisHandle = getHandle(root);
parentnode = null;
if (key == null) {
throw new kelondroException("startet search process with key == null");
/*
child = 0;
if (thisHandle == null) {
thenode = null;
Expand All @@ -290,95 +295,106 @@ protected void process(byte[] key) throws IOException {
thenode = getNode(thisHandle, null, 0);
found = true;
}
} else {
thenode = null;
child = 0;
found = false;
int c;
byte[] k;
TreeSet visitedNodeKeys = new TreeSet(loopDetectionOrder); // to detect loops
// System.out.println("Starting Compare Loop in Database " + filename); // debug
while (thisHandle != null) {
try {
parentnode = thenode;
thenode = getNode(thisHandle, thenode, (child == -1) ? leftchild : rightchild);
} catch (IllegalArgumentException e) {
logWarning("kelondroTree.Search.process: fixed a broken handle");
found = false;
return;
}
if (thenode == null) {
throw new kelondroException(filename, "kelondroTree.Search.process: thenode==null");
}
k = thenode.getKey();
if (k == null) {
return;
*/
}
thenode = null;
child = 0;
found = false;
int c;

TreeMap visitedNodeKeys = new TreeMap(loopDetectionOrder); // to detect loops
// System.out.println("Starting Compare Loop in Database " + filename); // debug
while (thisHandle != null) {
try {
parentnode = thenode;
thenode = getNode(thisHandle, thenode, (child == -1) ? leftchild : rightchild);
} catch (IllegalArgumentException e) {
logWarning("kelondroTree.Search.process: fixed a broken handle");
found = false;
return;
}
if (thenode == null) throw new kelondroException(filename, "kelondroTree.Search.process: thenode==null");

keybuffer = thenode.getKey();
if (keybuffer == null) {
// this is an error. distinguish two cases:
// 1. thenode is a leaf node. Then this error can be fixed if we can consider this node as a good node to be replaced with a new value
// 2. thenode is not a leaf node. An exception must be thrown
if ((thenode.getOHHandle(leftchild) == null) && (thenode.getOHHandle(rightchild) == null)) {
// case 1: recover
deleteNode(thisHandle);
thenode = parentnode;
found = false;
return;
} else {
// case 2: fail
throw new kelondroException("found key during search process with key == null");
}
if (visitedNodeKeys.contains(k)) {
// we have loops in the database.
// to fix this, all affected nodes must be patched
thenode.setOHByte(magic, (byte) 1);
thenode.setOHByte(balance, (byte) 0);
thenode.setOHHandle(parent, null);
thenode.setOHHandle(leftchild, null);
thenode.setOHHandle(rightchild, null);
thenode.commit(CP_NONE);
logWarning("kelondroTree.Search.process: database contains loops; the loop-nodes have been auto-fixed");
found = false;
return;
}
// System.out.println("Comparing key = '" + new String(key) + "' with '" + otherkey + "':"); // debug
c = objectOrder.compare(key, k);
// System.out.println(c); // debug
if (c == 0) {
found = true;
// System.out.println("DEBUG: search for " + new String(key) + " ended with status=" + ((found) ? "found" : "not-found") + ", node=" + ((thenode == null) ? "NULL" : thenode.toString()) + ", parent=" + ((parentnode == null) ? "NULL" : parentnode.toString()));
return;
} else if (c < 0) {
child = -1;
thisHandle = thenode.getOHHandle(leftchild);
} else {
child = 1;
thisHandle = thenode.getOHHandle(rightchild);
}
visitedNodeKeys.add(k);
}
if (visitedNodeKeys.containsKey(keybuffer)) {
// we have loops in the database.
// to fix this, all affected nodes must be patched
thenode.setOHByte(magic, (byte) 1);
thenode.setOHByte(balance, (byte) 0);
thenode.setOHHandle(parent, null);
thenode.setOHHandle(leftchild, null);
thenode.setOHHandle(rightchild, null);
thenode.commit(CP_NONE);
logWarning("kelondroTree.Search.process: database contains loops; the loop-nodes have been auto-fixed");
found = false;
return;
}
// System.out.println("Comparing key = '" + new String(key) + "' with '" + otherkey + "':"); // debug
c = objectOrder.compare(key, keybuffer);
// System.out.println(c); // debug
if (c == 0) {
found = true;
// System.out.println("DEBUG: search for " + new String(key) + " ended with status=" + ((found) ? "found" : "not-found") + ", node=" + ((thenode == null) ? "NULL" : thenode.toString()) + ", parent=" + ((parentnode == null) ? "NULL" : parentnode.toString()));
return;
} else if (c < 0) {
child = -1;
thisHandle = thenode.getOHHandle(leftchild);
} else {
child = 1;
thisHandle = thenode.getOHHandle(rightchild);
}
visitedNodeKeys.put(keybuffer, null);
}
// System.out.println("DEBUG: search for " + new String(key) + " ended with status=" + ((found) ? "found" : "not-found") + ", node=" + ((thenode == null) ? "NULL" : thenode.toString()) + ", parent=" + ((parentnode == null) ? "NULL" : parentnode.toString()));
// we reached a node where we must insert the new value
// the parent of this new value can be obtained by getParent()
// all values are set, just return
}

public boolean found() {
return found;
}
public boolean found() {
return found;
}

public Node getMatcher() {
if (found) return thenode;
throw new IllegalArgumentException("wrong access of matcher");
}
public Node getMatcher() {
if (found) return thenode;
throw new IllegalArgumentException("wrong access of matcher");
}

public Node getParent() {
if (found) return parentnode;
return thenode;
}
public Node getParent() {
if (found) return parentnode;
return thenode;
}

public boolean isRoot() {
if (found) throw new IllegalArgumentException("wrong access of isRoot");
return (child == 0);
}
public boolean isRoot() {
if (found) throw new IllegalArgumentException("wrong access of isRoot");
return (child == 0);
}

public boolean isLeft() {
if (found) throw new IllegalArgumentException("wrong access of leftchild");
return (child == -1);
}
public boolean isRight() {
if (found) throw new IllegalArgumentException("wrong access of leftchild");
return (child == 1);
}
public boolean isLeft() {
if (found) throw new IllegalArgumentException("wrong access of leftchild");
return (child == -1);
}

public boolean isRight() {
if (found) throw new IllegalArgumentException("wrong access of leftchild");
return (child == 1);
}
}

public synchronized boolean isChild(Node childn, Node parentn, int child) {
Expand Down Expand Up @@ -442,10 +458,10 @@ public kelondroRow.Entry put(kelondroRow.Entry newrow) throws IOException {
// check consistency and link new node to parent node
byte parentBalance;
if (writeSearchObj.isLeft()) {
if (parentNode.getOHHandle(leftchild) != null) throw new kelondroException(filename, "tried to create leftchild node twice");
if (parentNode.getOHHandle(leftchild) != null) throw new kelondroException(filename, "tried to create leftchild node twice. parent=" + new String(parentNode.getKey()) + ", leftchild=" + new String(new Node(parentNode.getOHHandle(leftchild), (Node) null, 0).getKey()));
parentNode.setOHHandle(leftchild, theNode.handle());
} else if (writeSearchObj.isRight()) {
if (parentNode.getOHHandle(rightchild) != null) throw new kelondroException(filename, "tried to create rightchild node twice");
if (parentNode.getOHHandle(rightchild) != null) throw new kelondroException(filename, "tried to create rightchild node twice. parent=" + new String(parentNode.getKey()) + ", rightchild=" + new String(new Node(parentNode.getOHHandle(rightchild), (Node) null, 0).getKey()));
parentNode.setOHHandle(rightchild, theNode.handle());
} else {
throw new kelondroException(filename, "neither left nor right child");
Expand Down

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