| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.services.io.FormatableArrayHolder |
| 4 | |
| 5 | Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.iapi.services.io; |
| 22 | |
| 23 | import org.apache.derby.iapi.services.io.ArrayInputStream; |
| 24 | |
| 25 | import org.apache.derby.iapi.services.io.StoredFormatIds; |
| 26 | import org.apache.derby.iapi.services.io.FormatIdUtil; |
| 27 | import org.apache.derby.iapi.services.io.ArrayUtil; |
| 28 | import org.apache.derby.iapi.services.io.Formatable; |
| 29 | |
| 30 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 31 | |
| 32 | import java.io.ObjectOutput; |
| 33 | import java.io.ObjectInput; |
| 34 | import java.io.IOException; |
| 35 | |
| 36 | import java.lang.reflect.Array; |
| 37 | |
| 38 | /** |
| 39 | * A formatable holder for an array of formatables. |
| 40 | * Used to avoid serializing arrays. |
| 41 | */ |
| 42 | public class FormatableArrayHolder implements Formatable |
| 43 | { |
| 44 | /******************************************************** |
| 45 | ** |
| 46 | ** This class implements Formatable. That means that it |
| 47 | ** can write itself to and from a formatted stream. If |
| 48 | ** you add more fields to this class, make sure that you |
| 49 | ** also write/read them with the writeExternal()/readExternal() |
| 50 | ** methods. |
| 51 | ** |
| 52 | ** If, inbetween releases, you add more fields to this class, |
| 53 | ** then you should bump the version number emitted by the getTypeFormatId() |
| 54 | ** method. |
| 55 | ** |
| 56 | ********************************************************/ |
| 57 | |
| 58 | // the array |
| 59 | private Object[] array; |
| 60 | |
| 61 | /** |
| 62 | * Niladic constructor for formatable |
| 63 | */ |
| 64 | public FormatableArrayHolder() |
| 65 | { |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Construct a FormatableArrayHolder using the input |
| 70 | * array. |
| 71 | * |
| 72 | * @param array the array to hold |
| 73 | */ |
| 74 | public FormatableArrayHolder(Object[] array) |
| 75 | { |
| 76 | if (SanityManager.DEBUG) |
| 77 | { |
| 78 | SanityManager.ASSERT(array != null, |
| 79 | "array input to constructor is null, code can't handle this."); |
| 80 | } |
| 81 | |
| 82 | this.array = array; |
| 83 | } |
| 84 | |
| 85 | /** |
| 86 | * Set the held array to the input array. |
| 87 | * |
| 88 | * @param array the array to hold |
| 89 | */ |
| 90 | public void setArray(Object[] array) |
| 91 | { |
| 92 | if (SanityManager.DEBUG) |
| 93 | { |
| 94 | SanityManager.ASSERT(array != null, |
| 95 | "array input to setArray() is null, code can't handle this."); |
| 96 | } |
| 97 | |
| 98 | this.array = array; |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Get the held array of formatables, and return |
| 103 | * it in an array of type inputClass. |
| 104 | * |
| 105 | * @param inputClass the class to use for the returned array |
| 106 | * |
| 107 | * @return an array of formatables |
| 108 | */ |
| 109 | public Object[] getArray(Class inputClass) |
| 110 | { |
| 111 | Object[] outArray = (Object[])Array.newInstance(inputClass, array.length); |
| 112 | |
| 113 | /* |
| 114 | ** HACK: on as400 the following arraycopy() throws an |
| 115 | ** ArrayStoreException because the output array isn't |
| 116 | ** assignment compatible with the input array. This |
| 117 | ** is a bug on as400, but to get around it we are |
| 118 | ** going to do an element by element copy. |
| 119 | */ |
| 120 | //System.arraycopy(array, 0, outArray, 0, outArray.length); |
| 121 | for (int i = 0; i < outArray.length; i++) |
| 122 | { |
| 123 | outArray[i] = array[i]; |
| 124 | } |
| 125 | |
| 126 | return outArray; |
| 127 | } |
| 128 | |
| 129 | ////////////////////////////////////////////// |
| 130 | // |
| 131 | // FORMATABLE |
| 132 | // |
| 133 | ////////////////////////////////////////////// |
| 134 | /** |
| 135 | * Write this array out |
| 136 | * |
| 137 | * @param out write bytes here |
| 138 | * |
| 139 | * @exception IOException thrown on error |
| 140 | */ |
| 141 | public void writeExternal(ObjectOutput out) throws IOException |
| 142 | { |
| 143 | if (SanityManager.DEBUG) |
| 144 | { |
| 145 | SanityManager.ASSERT(array != null, "Array is null, which isn't expected"); |
| 146 | } |
| 147 | |
| 148 | ArrayUtil.writeArrayLength(out, array); |
| 149 | ArrayUtil.writeArrayItems(out, array); |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Read this array from a stream of stored objects. |
| 154 | * |
| 155 | * @param in read this. |
| 156 | * |
| 157 | * @exception IOException thrown on error |
| 158 | * @exception ClassNotFoundException thrown on error |
| 159 | */ |
| 160 | public void readExternal(ObjectInput in) |
| 161 | throws IOException, ClassNotFoundException |
| 162 | { |
| 163 | array = new Object[ArrayUtil.readArrayLength(in)]; |
| 164 | ArrayUtil.readArrayItems(in, array); |
| 165 | } |
| 166 | public void readExternal(ArrayInputStream in) |
| 167 | throws IOException, ClassNotFoundException |
| 168 | { |
| 169 | array = new Formatable[ArrayUtil.readArrayLength(in)]; |
| 170 | ArrayUtil.readArrayItems(in, array); |
| 171 | } |
| 172 | |
| 173 | |
| 174 | /** |
| 175 | * Get the formatID which corresponds to this class. |
| 176 | * |
| 177 | * @return the formatID of this class |
| 178 | */ |
| 179 | public int getTypeFormatId() { return StoredFormatIds.FORMATABLE_ARRAY_HOLDER_V01_ID; } |
| 180 | } |