/**
* Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
*
* Licensed 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 com.linkedin.pinot.core.startree;
import com.google.common.collect.HashBiMap;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class StarTree implements StarTreeInterf {
private static final Logger LOGGER = LoggerFactory.getLogger(StarTree.class);
private static final long serialVersionUID = 1L;
StarTreeIndexNode root;
int numNodes = 0;
private HashBiMap<String, Integer> dimensionNameToIndexMap;
public StarTree(StarTreeIndexNode root, HashBiMap<String, Integer> dimensionNameToIndexMap) {
this.root = root;
this.dimensionNameToIndexMap = dimensionNameToIndexMap;
}
/**
* {@inheritDoc}
* @return
*/
@Override
public StarTreeIndexNodeInterf getRoot() {
return root;
}
/**
* {@inheritDoc}
* @return
*/
@Override
public StarTreeFormatVersion getVersion() {
return StarTreeFormatVersion.ON_HEAP;
}
/**
* Returns the total number of nodes in the star tree.
* For backward compatibility (trees without this info), it computes
* the number of nodes on the fly.
*
* @return
*/
@Override
public int getNumNodes() {
if (numNodes == 0) {
numNodes = getNumNodes(root);
}
return numNodes;
}
/**
* {@inheritDoc}
* @return
*/
@Override
public HashBiMap<String, Integer> getDimensionNameToIndexMap() {
return dimensionNameToIndexMap;
}
/**
* {@inheritDoc}
* @param outputFile
* @throws IOException
*/
@Override
public void writeTree(File outputFile)
throws IOException {
OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(outputFile));
ObjectOutputStream oos = new ObjectOutputStream(outputStream);
try {
oos.writeObject(this);
} catch (Exception e) {
LOGGER.error("Exception caught while writing StarTree file", e);
} finally {
oos.close();
}
}
@Override
public void printTree() {
printTree(root, 0);
}
/**
* Helper method to print the tree.
* @param root
* @param level
*/
public void printTree(StarTreeIndexNode root, int level) {
for (int i = 0; i < level; i++) {
System.out.print(" ");
}
System.out.println(root);
if (!root.isLeaf()) {
for (StarTreeIndexNode child : root.getChildren().values()) {
printTree(child, level + 1);
}
}
}
/**
* Helper method that computes and returns the number of nodes
* in the tree (by performing a dfs on the tree).
*
* @param root
* @return
*/
private static int getNumNodes(StarTreeIndexNode root) {
if (root == null) {
return 0;
}
int numNodes = 1;
Map<Integer, StarTreeIndexNode> children = root.getChildren();
if (children != null) {
for (StarTreeIndexNode child : children.values()) {
numNodes += getNumNodes(child);
}
}
return numNodes;
}
}