tfloatarraylist.java

这是一个matlab的java实现。里面有许多内容。请大家慢慢捉摸。

     *
     * @param from the inclusive index at which to start reversing
     * @param to the exclusive index at which to stop reversing
     */
    public void reverse(int from, int to) {
        if (from == to) {
            return;             // nothing to do
        }
        if (from > to) {
            throw new IllegalArgumentException("from cannot be greater than to");
        }
        for (int i = from, j = to - 1; i < j; i++, j--) {
            swap(i, j);
        }
    }

    /**
     * Shuffle the elements of the list using the specified random
     * number generator.
     *
     * @param rand a <code>Random</code> value
     */
    public void shuffle(Random rand) {
        for (int i = _pos; i-- > 1;) {
            swap(i, rand.nextInt(i));
        }
    }

    /**
     * Swap the values at offsets <tt>i</tt> and <tt>j</tt>.
     *
     * @param i an offset into the data array
     * @param j an offset into the data array
     */
    private final void swap(int i, int j) {
        float tmp = _data[i];
        _data[i] = _data[j];
        _data[j] = tmp;
    }

    // copying

    /**
     * Returns a clone of this list.  Since this is a primitive
     * collection, this will be a deep clone.
     *
     * @return a deep clone of the list.
     */
    public Object clone() {
        Object o = null;
        try {
            o = super.clone();
        } catch (CloneNotSupportedException e) {
            // it's supported
        } // end of try-catch
        return o;
    }

    /**
     * Copies the contents of the list into a native array.
     *
     * @return an <code>float[]</code> value
     */
    public float[] toNativeArray() {
        return toNativeArray(0, _pos);
    }

    /**
     * Copies a slice of the list into a native array.
     *
     * @param offset the offset at which to start copying
     * @param len the number of values to copy.
     * @return an <code>float[]</code> value
     */
    public float[] toNativeArray(int offset, int len) {
        float[] rv = new float[len];
        toNativeArray(rv, offset, len);
        return rv;
    }

    /**
     * Copies a slice of the list into a native array.
     *
     * @param dest the array to copy into.
     * @param offset the offset of the first value to copy
     * @param len the number of values to copy.
     */
    public void toNativeArray(float[] dest, int offset, int len) {
        if (len == 0) {
            return;             // nothing to copy
        }
        if (offset < 0 || offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        System.arraycopy(_data, 0, dest, offset, len);
    }

    // comparing

    /**
     * Compares this list to another list, value by value.
     *
     * @param other the object to compare against
     * @return true if other is a TFloatArrayList and has exactly the
     * same values.
     */
    public boolean equals(Object other) {
        if (other == this) {
            return true;
        } else if (other instanceof TFloatArrayList) {
            TFloatArrayList that = (TFloatArrayList)other;
            if (that.size() != this.size()) {
                return false;
            } else {
                for (int i = _pos; i-- > 0;) {
                    if (this._data[i] != that._data[i]) {
                        return false;
                    }
                }
                return true;
            }
        } else {
            return false;
        }
    }

    // procedures

    /**
     * Applies the procedure to each value in the list in ascending
     * (front to back) order.
     *
     * @param procedure a <code>TFloatProcedure</code> value
     * @return true if the procedure did not terminate prematurely.
     */
    public boolean forEach(TFloatProcedure procedure) {
        for (int i = 0; i < _pos; i++) {
            if (! procedure.execute(_data[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Applies the procedure to each value in the list in descending
     * (back to front) order.
     *
     * @param procedure a <code>TFloatProcedure</code> value
     * @return true if the procedure did not terminate prematurely.
     */
    public boolean forEachDescending(TFloatProcedure procedure) {
        for (int i = _pos; i-- > 0;) {
            if (! procedure.execute(_data[i])) {
                return false;
            }
        }
        return true;
    }

    // sorting

    /**
     * Sort the values in the list (ascending) using the Sun quicksort
     * implementation.
     *
     * @see java.util.Arrays#sort
     */
    public void sort() {
        Arrays.sort(_data, 0, _pos);
    }

    /**
     * Sort a slice of the list (ascending) using the Sun quicksort
     * implementation.
     *
     * @param fromIndex the index at which to start sorting (inclusive)
     * @param toIndex the index at which to stop sorting (exclusive)
     * @see java.util.Arrays#sort
     */
    public void sort(int fromIndex, int toIndex) {
        Arrays.sort(_data, fromIndex, toIndex);
    }

    // filling

    /**
     * Fills every slot in the list with the specified value.
     *
     * @param val the value to use when filling
     */
    public void fill(float val) {
        Arrays.fill(_data, 0, _pos, val);
    }

    /**
     * Fills a range in the list with the specified value.
     *
     * @param fromIndex the offset at which to start filling (inclusive)
     * @param toIndex the offset at which to stop filling (exclusive)
     * @param val the value to use when filling
     */
    public void fill(int fromIndex, int toIndex, float val) {
        Arrays.fill(_data, fromIndex, toIndex, val);
    }

    // searching

    /**
     * Performs a binary search for <tt>value</tt> in the entire list.
     * Note that you <b>must</b> @{link #sort sort} the list before
     * doing a search.
     *
     * @param value the value to search for
     * @return the absolute offset in the list of the value, or its
     * negative insertion point into the sorted list.
     */
    public int binarySearch(float value) {
        return binarySearch(value, 0, _pos);
    }

    /**
     * Performs a binary search for <tt>value</tt> in the specified
     * range.  Note that you <b>must</b> @{link #sort sort} the list
     * or the range before doing a search.
     *
     * @param value the value to search for
     * @param fromIndex the lower boundary of the range (inclusive)
     * @param toIndex the upper boundary of the range (exclusive)
     * @return the absolute offset in the list of the value, or its
     * negative insertion point into the sorted list.
     */
    public int binarySearch(float value, int fromIndex, int toIndex) {
        if (fromIndex < 0) {
            throw new ArrayIndexOutOfBoundsException(fromIndex);
        }
        if (toIndex > _pos) {
            throw new ArrayIndexOutOfBoundsException(toIndex);
        }

        int low = fromIndex;
        int high = toIndex - 1;

        while (low <= high) {
            int mid = (low + high) >> 1;
            float midVal = _data[mid];

            if (midVal < value) {
                low = mid + 1;
            } else if (midVal > value) {
                high = mid - 1;
            } else {
                return mid; // value found
            }
        }
        return -(low + 1);  // value not found.
    }

    /**
     * Searches the list front to back for the index of
     * <tt>value</tt>.
     *
     * @param value an <code>float</code> value
     * @return the first offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int indexOf(float value) {
        return indexOf(0, value);
    }

    /**
     * Searches the list front to back for the index of
     * <tt>value</tt>, starting at <tt>offset</tt>.
     *
     * @param offset the offset at which to start the linear search
     * (inclusive)
     * @param value an <code>float</code> value
     * @return the first offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int indexOf(int offset, float value) {
        for (int i = offset; i < _pos; i++) {
            if (_data[i] == value) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Searches the list back to front for the last index of
     * <tt>value</tt>.
     *
     * @param value an <code>float</code> value
     * @return the last offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int lastIndexOf(float value) {
        return lastIndexOf(_pos, value);
    }

    /**
     * Searches the list back to front for the last index of
     * <tt>value</tt>, starting at <tt>offset</tt>.
     *
     * @param offset the offset at which to start the linear search
     * (exclusive)
     * @param value an <code>float</code> value
     * @return the last offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int lastIndexOf(int offset, float value) {
        for (int i = offset; i-- > 0;) {
            if (_data[i] == value) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Searches the list for <tt>value</tt>
     *
     * @param value an <code>float</code> value
     * @return true if value is in the list.
     */
    public boolean contains(float value) {
        return lastIndexOf(value) >= 0;
    }

    /**
     * Searches the list for values satisfying <tt>condition</tt> in
     * the manner of the *nix <tt>grep</tt> utility.
     *
     * @param condition a condition to apply to each element in the list
     * @return a list of values which match the condition.
     */
    public TFloatArrayList grep(TFloatProcedure condition) {
        TFloatArrayList list = new TFloatArrayList();
        for (int i = 0; i < _pos; i++) {
            if (condition.execute(_data[i])) {
                list.add(_data[i]);
            }
        }
        return list;
    }

    /**
     * Searches the list for values which do <b>not</b> satisfy
     * <tt>condition</tt>.  This is akin to *nix <code>grep -v</code>.
     *
     * @param condition a condition to apply to each element in the list
     * @return a list of values which do not match the condition.
     */
    public TFloatArrayList inverseGrep(TFloatProcedure condition) {
        TFloatArrayList list = new TFloatArrayList();
        for (int i = 0; i < _pos; i++) {
            if (! condition.execute(_data[i])) {
                list.add(_data[i]);
            }
        }
        return list;
    }

    /**
     * Finds the maximum value in the list.
     *
     * @return the largest value in the list.
     * @exception IllegalStateException if the list is empty
     */
    public float max() {
        if (size() == 0) {
            throw new IllegalStateException("cannot find maximum of an empty list");
        }
        float max = _data[_pos - 1];
        for (int i = _pos - 1; i-- > 0;) {
            max = Math.max(max, _data[_pos]);
        }
        return max;
    }

    /**
     * Finds the minimum value in the list.
     *
     * @return the smallest value in the list.
     * @exception IllegalStateException if the list is empty
     */
    public float min() {
        if (size() == 0) {
            throw new IllegalStateException("cannot find minimum of an empty list");
        }
        float min = _data[_pos - 1];
        for (int i = _pos - 1; i-- > 0;) {
            min = Math.min(min, _data[_pos]);
        }
        return min;
    }

    // stringification

    /**
     * Returns a String representation of the list, front to back.
     *
     * @return a <code>String</code> value
     */
    public String toString() {
        final StringBuffer buf = new StringBuffer("{");
        forEach(new TFloatProcedure() {
                public boolean execute(float val) {
                    buf.append(val);
                    buf.append(", ");
                    return true;
                }
            });
        buf.append("}");
        return buf.toString();
    }
} // TFloatArrayList