| 1 | /* |
| 2 | |
| 3 | Derby - Class com.ihost.cs.DoubleProperties |
| 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.util; |
| 22 | |
| 23 | import java.util.Properties; |
| 24 | import java.util.Enumeration; |
| 25 | |
| 26 | /** |
| 27 | A properties object that links two independent |
| 28 | properties together. The read property set is always |
| 29 | searched first, with the write property set being |
| 30 | second. But any put() calls are always made directly to |
| 31 | the write object. |
| 32 | |
| 33 | Only the put(), keys() and getProperty() methods are supported |
| 34 | by this class. |
| 35 | */ |
| 36 | |
| 37 | public final class DoubleProperties extends Properties { |
| 38 | |
| 39 | private final Properties read; |
| 40 | private final Properties write; |
| 41 | |
| 42 | public DoubleProperties(Properties read, Properties write) { |
| 43 | this.read = read; |
| 44 | this.write = write; |
| 45 | } |
| 46 | |
| 47 | public Object put(Object key, Object value) { |
| 48 | return write.put(key, value); |
| 49 | } |
| 50 | |
| 51 | public String getProperty(String key) { |
| 52 | |
| 53 | return read.getProperty(key, write.getProperty(key)); |
| 54 | } |
| 55 | |
| 56 | public String getProperty(String key, String defaultValue) { |
| 57 | return read.getProperty(key, write.getProperty(key, defaultValue)); |
| 58 | |
| 59 | } |
| 60 | |
| 61 | public Enumeration propertyNames() { |
| 62 | |
| 63 | Properties p = new Properties(); |
| 64 | |
| 65 | if (write != null) { |
| 66 | |
| 67 | for (Enumeration e = write.propertyNames(); e.hasMoreElements(); ) { |
| 68 | String key = (String) e.nextElement(); |
| 69 | p.put(key, write.getProperty(key)); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | if (read != null) { |
| 74 | for (Enumeration e = read.propertyNames(); e.hasMoreElements(); ) { |
| 75 | String key = (String) e.nextElement(); |
| 76 | p.put(key, read.getProperty(key)); |
| 77 | } |
| 78 | } |
| 79 | return p.keys(); |
| 80 | } |
| 81 | } |