| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.store.access.GlobalXact |
| 4 | |
| 5 | Copyright 1999, 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.store.access; |
| 22 | |
| 23 | |
| 24 | /** |
| 25 | |
| 26 | This abstract class represents a global transaction id which can be tested |
| 27 | for equality against other transaction ids, which can be hashed into a |
| 28 | hash table, and which can be output as a string. |
| 29 | <P> |
| 30 | This class has 2 direct subclasses. |
| 31 | <UL> |
| 32 | <LI> org.apache.derby.iapi.store.access.xa.XAXactId : |
| 33 | this class is a specific implementation of the JTA Xid interface |
| 34 | <LI> org.apache.derby.impl.store.access.GlobalXactId : |
| 35 | this class represents internal cloudscape transaction ids |
| 36 | </UL> |
| 37 | <P> |
| 38 | The main reason for this class is to ensure that equality etc. works in a |
| 39 | consistent way across both subclasses. |
| 40 | **/ |
| 41 | |
| 42 | public abstract class GlobalXact { |
| 43 | |
| 44 | /************************************************************************** |
| 45 | * Protected Fields of the class |
| 46 | ************************************************************************** |
| 47 | */ |
| 48 | protected int format_id; |
| 49 | protected byte[] global_id; |
| 50 | protected byte[] branch_id; |
| 51 | |
| 52 | public boolean equals(Object other) |
| 53 | { |
| 54 | if (other == this) |
| 55 | return true; |
| 56 | |
| 57 | if (other instanceof GlobalXact) { |
| 58 | |
| 59 | GlobalXact other_xact = (GlobalXact) other; |
| 60 | |
| 61 | return( |
| 62 | java.util.Arrays.equals( |
| 63 | other_xact.global_id, |
| 64 | this.global_id) && |
| 65 | java.util.Arrays.equals( |
| 66 | other_xact.branch_id, |
| 67 | this.branch_id) && |
| 68 | other_xact.format_id == this.format_id); |
| 69 | |
| 70 | } |
| 71 | |
| 72 | return false; |
| 73 | } |
| 74 | |
| 75 | public String toString() |
| 76 | { |
| 77 | String globalhex = ""; |
| 78 | String branchhex = ""; |
| 79 | if (global_id != null) |
| 80 | { |
| 81 | int mask = 0; |
| 82 | for (int i = 0; i < global_id.length; i++) |
| 83 | { |
| 84 | mask = (global_id[i] & 0xFF); |
| 85 | globalhex += Integer.toHexString(mask); |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | if (branch_id != null) |
| 90 | { |
| 91 | int mask = 0; |
| 92 | for (int i = 0; i < branch_id.length; i++) |
| 93 | { |
| 94 | mask = (branch_id[i] & 0xFF); |
| 95 | branchhex += Integer.toHexString(mask); |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | return("(" + format_id + "," + globalhex + "," + branchhex + ")"); |
| 100 | |
| 101 | } |
| 102 | |
| 103 | |
| 104 | /** |
| 105 | Provide a hashCode which is compatable with the equals() method. |
| 106 | |
| 107 | @see java.lang.Object#hashCode |
| 108 | **/ |
| 109 | public int hashCode() |
| 110 | { |
| 111 | // make sure hash does not overflow int, the only unknown is |
| 112 | // format_id. Lop off top bits. |
| 113 | int hash = global_id.length + branch_id.length + (format_id & 0xFFFFFFF); |
| 114 | |
| 115 | for (int i = 0; i < global_id.length; i++) |
| 116 | { |
| 117 | hash += global_id[i]; |
| 118 | } |
| 119 | for (int i = 0; i < branch_id.length; i++) |
| 120 | { |
| 121 | hash += branch_id[i]; |
| 122 | } |
| 123 | |
| 124 | return(hash); |
| 125 | } |
| 126 | |
| 127 | } |
| 128 | |
| 129 | |
| 130 | |