edu.uiowa.icts.util.TopN.java Source code

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Here is the source code for edu.uiowa.icts.util.TopN.java

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package edu.uiowa.icts.util;

/*
 * #%L
 * spring-utils
 * %%
 * Copyright (C) 2010 - 2015 University of Iowa Institute for Clinical and Translational Science (ICTS)
 * %%
 * 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.
 * #L%
 */

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * <p>TopN class.</p>
 *
 * @author schappetj
 * @version $Id: $
 */
public class TopN<T> {
    private static final Log log = LogFactory.getLog(TopN.class);

    LinkedList<Double> topValues = new LinkedList<Double>();

    List<T> theList = new LinkedList<T>();

    int count;

    /**
     * <p>Constructor for TopN.</p>
     *
     * @param count a int.
     */
    public TopN(int count) {
        this.count = count;
        reset();
    }

    /**
     * <p>Constructor for TopN.</p>
     */
    public TopN() {
        this.count = 100;
        reset();
    }

    /**
     * <p>main.</p>
     *
     * @param args an array of {@link java.lang.String} objects.
     */
    public static void main(String args[]) {
        TopN<Double> top10 = new TopN<Double>(10);
        Random r = new Random();
        for (int i = 0; i < 10000; i++) {
            double d = r.nextDouble();
            int pos = top10.inTopN(d);
            if (pos > 0) {
                log.debug(i + ":  Rank: " + pos + " is in top 10: " + d);
            }
        }

        top10.print();
        log.debug("size: " + top10.size());
        log.debug("max: " + top10.max());

    }

    /**
     * <p>reset.</p>
     */
    public void reset() {
        topValues = new LinkedList<Double>();
        theList = new ArrayList<T>();
        for (@SuppressWarnings("unused")
        int i = 0; topValues.size() < count; i++) {
            topValues.push(0d);
            theList.add(null);
        }
    }

    /**
     * <p>inTopN.</p>
     *
     * @param current a {@link java.lang.Double} object.
     * @return a int.
     */
    public int inTopN(Double current) {
        return inTopN(current, null);
    }

    /**
     * <p>inTopN.</p>
     *
     * @param current a {@link java.lang.Double} object.
     * @param obj a T object.
     * @return a int.
     */
    public int inTopN(Double current, T obj) {
        int i = 0;
        for (Double d : topValues) {

            if (current > d) {
                insert(current, i, obj);
                return i;
            }
            i++;
        }
        return -1;
    }

    /**
     * <p>inBottomN.</p>
     *
     * @param current a {@link java.lang.Double} object.
     * @param obj a T object.
     * @return a int.
     */
    public int inBottomN(Double current, T obj) {
        // TODO Auto-generated method stub
        int i = 0;
        for (Double d : topValues) {

            if (current < d) {
                insert(current, i, obj);
                return i;
            }
            i++;
        }
        return -1;
    }

    /**
     * <p>size.</p>
     *
     * @return a int.
     */
    public int size() {
        return topValues.size();
    }

    /**
     * <p>print.</p>
     */
    public void print() {
        log.debug("List: " + topValues.size());
        int i = 0;
        for (Double d : topValues) {
            log.debug("print i: " + i++ + ": " + d);
        }
    }

    /**
     * <p>max.</p>
     *
     * @return a {@link java.lang.Double} object.
     */
    public Double max() {

        return topValues.get(0);
    }

    /**
     * <p>getList.</p>
     *
     * @return a {@link java.util.List} object.
     */
    public List<T> getList() {
        return theList;
    }

    private void insert(Double current, int pos, T obj) {
        if (pos < count) {
            double oldVal = topValues.get(pos);
            this.topValues.set(pos, current);

            T oldObj = theList.get(pos);
            this.theList.set(pos, obj);

            insert(oldVal, pos + 1, oldObj);
        }

    }

}