Raymond | dee0849 | 2015-04-02 10:43:13 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
| 3 | * contributor license agreements. See the NOTICE file distributed with |
| 4 | * this work for additional information regarding copyright ownership. |
| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
| 6 | * (the "License"); you may not use this file except in compliance with |
| 7 | * the License. You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | */ |
| 17 | package org.apache.commons.math.util; |
| 18 | |
| 19 | |
| 20 | /** |
| 21 | * Provides a standard interface for double arrays. Allows different |
| 22 | * array implementations to support various storage mechanisms |
| 23 | * such as automatic expansion, contraction, and array "rolling". |
| 24 | * |
| 25 | * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $ |
| 26 | */ |
| 27 | public interface DoubleArray { |
| 28 | |
| 29 | /** |
| 30 | * Returns the number of elements currently in the array. Please note |
| 31 | * that this may be different from the length of the internal storage array. |
| 32 | * |
| 33 | * @return number of elements |
| 34 | */ |
| 35 | int getNumElements(); |
| 36 | |
| 37 | /** |
| 38 | * Returns the element at the specified index. Note that if an |
| 39 | * out of bounds index is supplied a ArrayIndexOutOfBoundsException |
| 40 | * will be thrown. |
| 41 | * |
| 42 | * @param index index to fetch a value from |
| 43 | * @return value stored at the specified index |
| 44 | * @throws ArrayIndexOutOfBoundsException if <code>index</code> is less than |
| 45 | * zero or is greater than <code>getNumElements() - 1</code>. |
| 46 | */ |
| 47 | double getElement(int index); |
| 48 | |
| 49 | /** |
| 50 | * Sets the element at the specified index. If the specified index is greater than |
| 51 | * <code>getNumElements() - 1</code>, the <code>numElements</code> property |
| 52 | * is increased to <code>index +1</code> and additional storage is allocated |
| 53 | * (if necessary) for the new element and all (uninitialized) elements |
| 54 | * between the new element and the previous end of the array). |
| 55 | * |
| 56 | * @param index index to store a value in |
| 57 | * @param value value to store at the specified index |
| 58 | * @throws ArrayIndexOutOfBoundsException if <code>index</code> is less than |
| 59 | * zero. |
| 60 | */ |
| 61 | void setElement(int index, double value); |
| 62 | |
| 63 | /** |
| 64 | * Adds an element to the end of this expandable array |
| 65 | * |
| 66 | * @param value to be added to end of array |
| 67 | */ |
| 68 | void addElement(double value); |
| 69 | |
| 70 | /** |
| 71 | * <p> |
| 72 | * Adds an element to the end of the array and removes the first |
| 73 | * element in the array. Returns the discarded first element. |
| 74 | * The effect is similar to a push operation in a FIFO queue. |
| 75 | * </p> |
| 76 | * <p> |
| 77 | * Example: If the array contains the elements 1, 2, 3, 4 (in that order) |
| 78 | * and addElementRolling(5) is invoked, the result is an array containing |
| 79 | * the entries 2, 3, 4, 5 and the value returned is 1. |
| 80 | * </p> |
| 81 | * |
| 82 | * @param value the value to be added to the array |
| 83 | * @return the value which has been discarded or "pushed" out of the array |
| 84 | * by this rolling insert |
| 85 | */ |
| 86 | double addElementRolling(double value); |
| 87 | |
| 88 | /** |
| 89 | * Returns a double[] array containing the elements of this |
| 90 | * <code>DoubleArray</code>. If the underlying implementation is |
| 91 | * array-based, this method should always return a copy, rather than a |
| 92 | * reference to the underlying array so that changes made to the returned |
| 93 | * array have no effect on the <code>DoubleArray.</code> |
| 94 | * |
| 95 | * @return all elements added to the array |
| 96 | */ |
| 97 | double[] getElements(); |
| 98 | |
| 99 | /** |
| 100 | * Clear the double array |
| 101 | */ |
| 102 | void clear(); |
| 103 | |
| 104 | } |