/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
package com.espertech.esper.collection;
import java.util.ArrayList;
/**
* Sorted, reference-counting set based on an ArrayList implementation that it being kept sorted.
*/
public class SortedDoubleVector {
private ArrayList<Double> values;
/**
* Constructor.
*/
public SortedDoubleVector() {
values = new ArrayList<Double>();
}
public SortedDoubleVector(ArrayList<Double> values) {
this.values = values;
}
/**
* Clear out the collection.
*/
public void clear() {
values.clear();
}
/**
* Returns the number of items in the collection.
*
* @return size
*/
public int size() {
return values.size();
}
/**
* Returns the value at a given index.
*
* @param index for which to return value for
* @return value at index
*/
public double getValue(int index) {
return values.get(index);
}
/**
* Add a value to the collection.
*
* @param value is the double-type value to add
*/
public void add(double value) {
if (Double.isNaN(value)) {
return;
}
int index = findInsertIndex(value);
if (index == -1) {
values.add(value);
} else {
values.add(index, value);
}
}
/**
* Remove a value from the collection.
*
* @param value to remove
* @throws IllegalStateException if the value has not been added
*/
public void remove(double value) {
if (Double.isNaN(value)) {
return;
}
int index = findInsertIndex(value);
if (index == -1) {
throw new IllegalStateException("Value not found in collection");
}
Double valueAtIndex = values.get(index);
if ((valueAtIndex != null) && (!valueAtIndex.equals(value))) {
throw new IllegalStateException("Value not found in collection");
}
values.remove(index);
}
/**
* Returns underlying ArrayList, for testing purposes only.
*
* @return sorted double values list
*/
public ArrayList<Double> getValues() {
return values;
}
/**
* Returns the index into which to insert to.
* Proptected access level for convenient testing.
*
* @param value to find insert index
* @return position to insert the value to, or -1 to indicate to add to the end.
*/
protected int findInsertIndex(double value) {
if (values.size() > 2) {
int startIndex = values.size() >> 1;
double startValue = values.get(startIndex);
int insertAt;
if (value < startValue) {
// find in lower half
insertAt = findInsertIndex(0, startIndex - 1, value);
} else if (value > startValue) {
// find in upper half
insertAt = findInsertIndex(startIndex + 1, values.size() - 1, value);
} else {
// we hit the value
insertAt = startIndex;
}
if (insertAt == values.size()) {
return -1;
}
return insertAt;
}
if (values.size() == 2) {
if (value > values.get(1)) {
return -1;
} else if (value <= values.get(0)) {
return 0;
} else {
return 1;
}
}
if (values.size() == 1) {
if (value > values.get(0)) {
return -1;
} else {
return 0;
}
}
return -1;
}
private int findInsertIndex(int lowerBound, int upperBound, double value) {
while (true) {
if (upperBound == lowerBound) {
double valueLowerBound = values.get(lowerBound);
if (value <= valueLowerBound) {
return lowerBound;
} else {
return lowerBound + 1;
}
}
if (upperBound - lowerBound == 1) {
double valueLowerBound = values.get(lowerBound);
if (value <= valueLowerBound) {
return lowerBound;
}
double valueUpperBound = values.get(upperBound);
if (value > valueUpperBound) {
return upperBound + 1;
}
return upperBound;
}
int nextMiddle = lowerBound + ((upperBound - lowerBound) >> 1);
double valueAtMiddle = values.get(nextMiddle);
if (value < valueAtMiddle) {
// find in lower half
upperBound = nextMiddle - 1;
} else if (value > valueAtMiddle) {
// find in upper half
lowerBound = nextMiddle;
} else {
return nextMiddle;
}
}
}
}