Android Open Source - senselib Data Pool

• Back to Location/library  ↑

From Project

Back to project page senselib.

License

The source code is released under:

Copyright (c) 2013 Kaiwen Xu Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Softwa...

Java Source Code

/*
 * Copyright (c) 2013 Kaiwen Xu//from   ww  w  .  j  av a2s.  c  o m
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy 
 * of this software and associated documentation files (the "Software"), to 
 * deal in the Software without restriction, including without limitation the 
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
 * sell copies of the Software, and to permit persons to whom the Software is 
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in 
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
 * IN THE SOFTWARE.
 * 
 */

package net.kevxu.senselib.util;

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

/**
 * Data container which stores last n data, n is defined by poolSize. It uses
 * the concept of circular array, but the underlining data container uses
 * ArrayList due to the need of support generic. This data container is NOT
 * thread-safe, use with ABSOLUTE caution.
 * 
 * @author Kaiwen Xu
 * 
 * @param <T>
 *            Type of data to be stored.
 */
public class DataPool<T> {

  private int mPoolSize;

  private List<T> mPool;
  private int mStartPos;
  private int mEndPos;
  private int mSize;

  public DataPool(int poolSize) {
    mPoolSize = poolSize;
    mPool = new ArrayList<T>(poolSize);
    mStartPos = 0;
    mEndPos = 0;
    mSize = 0;

    for (int i = 0; i < poolSize; i++) {
      mPool.add(null);
    }
  }

  public int size() {
    return mSize;
  }

  public int getPoolSize() {
    return mPoolSize;
  }

  public void append(T values) {
    if (mSize < mPoolSize) {
      mPool.set(mEndPos, values);
      mEndPos = (mEndPos + 1) % mPoolSize;
      mSize++;
    } else {
      mStartPos = (mStartPos + 1) % mPoolSize;
      mPool.set(mEndPos, values);
      mEndPos = (mEndPos + 1) % mPoolSize;
    }
  }

  public T get(int i) {
    if (i < mSize) {
      return mPool.get((mStartPos + i) % mPoolSize);
    } else {
      throw new IndexOutOfBoundsException("i is larger than DataPool size.");
    }
  }

  public List<T> getList(int n) {
    if (n > mSize) {
      throw new IndexOutOfBoundsException("n is larger than DataPool size.");
    }

    List<T> fd = new ArrayList<T>(n);
    for (int i = 0; i < n; i++) {
      fd.add(get(i));
    }

    return fd;
  }

  public T getFromBack(int i) {
    return get(mSize - 1 - i);
  }

  public List<T> getListFromBack(int n) {
    if (n > mSize) {
      throw new IndexOutOfBoundsException("n is larger than DataPool size.");
    }

    List<T> pd = new ArrayList<T>(n);
    for (int i = 0; i < n; i++) {
      pd.add(getFromBack(i));
    }

    return pd;
  }

  @Override
  public String toString() {
    return mPool.toString();
  }

  public static void main(String[] args) {
    Random r = new Random();
    DataPool<float[]> pool = new DataPool<float[]>(5);

    // Appending data
    System.out.println("Appending data:");
    for (int i = 0; i < 10; i++) {
      float[] values = new float[3];
      for (int j = 0; j < 3; j++) {
        values[j] = (float) r.nextInt(10);
      }
      pool.append(values);

      StringBuilder sb = new StringBuilder();
      // sb.append("[");
      for (int idx = 0; idx < pool.size(); idx++) {
        sb.append("[");
        float[] getValues = pool.get(idx);
        for (int fidx = 0; fidx < 3; fidx++) {
          sb.append(getValues[fidx]);
          sb.append(", ");
        }
        sb.delete(sb.length() - 2, sb.length());
        sb.append("], ");
      }
      sb.delete(sb.length() - 2, sb.length());
      // sb.append("]");
      System.out.println(sb.toString());
    }
    System.out.println();

    // Test get
    System.out.println("Testing get:");
    for (int i = 0; i < 20; i++) {
      try {
        float[] value = pool.get(i);
        StringBuilder sb = new StringBuilder();
        sb.append("[");
        for (int j = 0; j < 3; j++) {
          sb.append(value[j]).append(", ");
        }
        sb.delete(sb.length() - 2, sb.length());
        sb.append("]");
        System.out.println(i + ": " + sb.toString());
      } catch (IndexOutOfBoundsException e) {
        e.printStackTrace();
      }
    }
    System.out.println();

    // Test getPrevious
    System.out.println("Testing getPrevious:");
    for (int n = 0; n < 10; n++) {
      try {
        List<float[]> pd = pool.getListFromBack(n);
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
          sb.append("[");
          for (int j = 0; j < 3; j++) {
            sb.append(pd.get(i)[j]).append(", ");
          }
          sb.delete(sb.length() - 2, sb.length());
          sb.append("], ");
        }
        if (n > 0)
          sb.delete(sb.length() - 2, sb.length());
        System.out.println("previous " + n + ": " + sb.toString());
      } catch (IndexOutOfBoundsException e) {
        e.printStackTrace();
      }
    }
    System.out.println();
  }
}

Java Source Code List

• Back to Location/library  ↑