| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.services.io.FormatableProperties |
| 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.FormatIdUtil; |
| 26 | import org.apache.derby.iapi.services.io.Formatable; |
| 27 | import org.apache.derby.iapi.services.io.StoredFormatIds; |
| 28 | |
| 29 | import java.util.Enumeration; |
| 30 | import java.util.Properties; |
| 31 | |
| 32 | import java.io.IOException; |
| 33 | import java.io.ObjectOutput; |
| 34 | import java.io.ObjectInput; |
| 35 | |
| 36 | /** |
| 37 | * A formatable holder for a java.util.Properties. |
| 38 | * Used to avoid serializing Properties. |
| 39 | */ |
| 40 | public class FormatableProperties extends Properties implements Formatable |
| 41 | { |
| 42 | /******************************************************** |
| 43 | ** |
| 44 | ** This class implements Formatable. That means that it |
| 45 | ** can write itself to and from a formatted stream. If |
| 46 | ** you add more fields to this class, make sure that you |
| 47 | ** also write/read them with the writeExternal()/readExternal() |
| 48 | ** methods. |
| 49 | ** |
| 50 | ** If, inbetween releases, you add more fields to this class, |
| 51 | ** then you should bump the version number emitted by the getTypeFormatId() |
| 52 | ** method. |
| 53 | ** |
| 54 | ********************************************************/ |
| 55 | |
| 56 | /** |
| 57 | * Niladic constructor for formatable |
| 58 | */ |
| 59 | public FormatableProperties() |
| 60 | { |
| 61 | this(null); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Creates an empty property list with the specified |
| 66 | * defaults. |
| 67 | * |
| 68 | * @param defaults the defaults |
| 69 | */ |
| 70 | public FormatableProperties(Properties defaults) |
| 71 | { |
| 72 | super(defaults); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | Clear the defaults from this Properties set. |
| 77 | This sets the default field to null and thus |
| 78 | breaks any link with the Properties set that |
| 79 | was the default. |
| 80 | */ |
| 81 | public void clearDefaults() { |
| 82 | defaults = null; |
| 83 | } |
| 84 | |
| 85 | ////////////////////////////////////////////// |
| 86 | // |
| 87 | // FORMATABLE |
| 88 | // |
| 89 | ////////////////////////////////////////////// |
| 90 | /** |
| 91 | * Write the properties out. Step through |
| 92 | * the enumeration and write the strings out |
| 93 | * in UTF. |
| 94 | * |
| 95 | * @param out write bytes here |
| 96 | * |
| 97 | * @exception IOException thrown on error |
| 98 | */ |
| 99 | public void writeExternal(ObjectOutput out) throws IOException |
| 100 | { |
| 101 | out.writeInt(size()); |
| 102 | for (Enumeration e = keys(); e.hasMoreElements(); ) |
| 103 | { |
| 104 | String key = (String)e.nextElement(); |
| 105 | out.writeUTF(key); |
| 106 | out.writeUTF(getProperty(key)); |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Read the properties from a stream of stored objects. |
| 112 | * |
| 113 | * @param in read this. |
| 114 | * |
| 115 | * @exception IOException thrown on error |
| 116 | */ |
| 117 | public void readExternal(ObjectInput in) |
| 118 | throws IOException |
| 119 | { |
| 120 | int size = in.readInt(); |
| 121 | for (; size > 0; size--) |
| 122 | { |
| 123 | put(in.readUTF(), in.readUTF()); |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | public void readExternal(ArrayInputStream in) |
| 128 | throws IOException |
| 129 | { |
| 130 | int size = in.readInt(); |
| 131 | for (; size > 0; size--) |
| 132 | { |
| 133 | put(in.readUTF(), in.readUTF()); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * Get the formatID which corresponds to this class. |
| 139 | * |
| 140 | * @return the formatID of this class |
| 141 | */ |
| 142 | public int getTypeFormatId() { return StoredFormatIds.FORMATABLE_PROPERTIES_V01_ID; } |
| 143 | } |