com.indeed.util.core.TreeTimer Maven / Gradle / Ivy
package com.indeed.util.core;
import java.util.Map;
import java.util.Stack;
import java.util.LinkedHashMap;
import javax.annotation.Nonnull;
/**
* Class to help keep a set of timings. Call push() with a name when timer should start, then call pop() when the timer should stop. If another push() is called prior to a pop
* the timing values begin to nest. If the same name is pushed/popped several times the times accumulate
* To dump all the timing information call toString()
*
* @author ahudson
*/
public class TreeTimer {
Stack timeStack = new Stack();
Stack nodeStack = new Stack();
Node root = new Node();
private static class Node {
long time = 0;
Map children = null;
Node getChild(String s) {
if (children == null) children = new LinkedHashMap();
Node child = children.get(s);
if (child == null) {
child = new Node();
children.put(s, child);
}
return child;
}
}
public void push(String s) {
Node node;
if (nodeStack.isEmpty()) {
node = root;
} else {
node = nodeStack.peek();
}
nodeStack.push(node.getChild(s));
timeStack.push(System.currentTimeMillis());
}
public int pop() {
if (!nodeStack.isEmpty()) {
Node node = nodeStack.pop();
long start = timeStack.pop();
long duration = System.currentTimeMillis() - start;
node.time += duration;
return (int) duration;
}
return -1;
}
// used for aligning output for prettier printing
private static long findMaxTime(Node n) {
long max = Long.MIN_VALUE;
for (Map.Entry entry : n.children.entrySet()) {
max = Math.max(max, entry.getValue().time);
}
return max;
}
private static void printNode(int indent, Node n, StringBuilder ret) {
if (n.children == null) return;
long max = findMaxTime(n);
int width = String.valueOf(max).length();
for (Map.Entry entry: n.children.entrySet()) {
ret.append(TreeTimer.leftpad(String.valueOf(entry.getValue().time), width + indent));
ret.append("ms ").append(entry.getKey()).append("\n");
printNode(indent + width + 3, entry.getValue(), ret);
}
}
/**
* Left-pads a String with spaces so it is length n. If the String
* is already at least length n, no padding is done.
*/
@Nonnull
private static String leftpad(@Nonnull String s, int n) {
return leftpad(s, n, ' ');
}
/**
* Left-pads a String with the specific padChar so it is length n. If the String
* is already at least length n, no padding is done.
*/
@Nonnull
private static String leftpad(@Nonnull String s, int n, char padChar) {
int diff = n - s.length();
if (diff <= 0) {
return s;
}
StringBuilder buf = new StringBuilder(n);
for (int i = 0; i < diff; ++i) {
buf.append(padChar);
}
buf.append(s);
return buf.toString();
}
@Override
public String toString() {
StringBuilder ret = new StringBuilder();
printNode(2, root, ret);
return ret.toString();
}
}