Coverage Report - org.apache.commons.configuration.SubnodeConfiguration
 
Classes in this File Line Coverage Branch Coverage Complexity
SubnodeConfiguration
100%
18/18
100%
2/2
1,667
 
 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.configuration;
 18  
 
 19  
 import org.apache.commons.configuration.tree.ConfigurationNode;
 20  
 
 21  
 /**
 22  
  * <p>
 23  
  * A specialized hierarchical configuration class that wraps a single node of
 24  
  * its parent configuration.
 25  
  * </p>
 26  
  * <p>
 27  
  * Configurations of this type are initialized with a parent configuration and a
 28  
  * configuration node of this configuration. This node becomes the root node of
 29  
  * the subnode configuration. All property accessor methods are evaluated
 30  
  * relative to this root node. A good use case for a
 31  
  * <code>SubnodeConfiguration</code> is when multiple properties from a
 32  
  * specific sub tree of the whole configuration need to be accessed. Then a
 33  
  * <code>SubnodeConfiguration</code> can be created with the parent node of
 34  
  * the affected sub tree as root node. This allows for simpler property keys and
 35  
  * is also more efficient.
 36  
  * </p>
 37  
  * <p>
 38  
  * A subnode configuration and its parent configuration operate on the same
 39  
  * hierarchy of configuration nodes. So if modifications are performed at the
 40  
  * subnode configuration, these changes are immideately visible in the parent
 41  
  * configuration. Analogously will updates of the parent configuration affect
 42  
  * the subnode configuration if the sub tree spanned by the subnode
 43  
  * configuration's root node is involved.
 44  
  * </p>
 45  
  * <p>
 46  
  * When a subnode configuration is created, it inherits the settings of its
 47  
  * parent configuration, e.g. some flags like the
 48  
  * <code>throwExceptionOnMissing</code> flag or the settings for handling list
 49  
  * delimiters) or the expression engine. If these settings are changed later in
 50  
  * either the subnode or the parent configuration, the changes are not visible
 51  
  * for each other. So you could create a subnode configuration, change its
 52  
  * expression engine without affecting the parent configuration.
 53  
  * </p>
 54  
  * <p>
 55  
  * From its purpose this class is quite similar to
 56  
  * <code>{@link SubsetConfiguration}</code>. The difference is that a subset
 57  
  * configuration of a hierarchical configuration may combine multiple
 58  
  * configuration nodes from different sub trees of the configuration, while all
 59  
  * nodes in a subnode configuration belong to the same sub tree. If an
 60  
  * application can live with this limitation, it is recommended to use this
 61  
  * class instead of <code>SubsetConfiguration</code> because creating a subset
 62  
  * configuration is more expensive than creating a subnode configuration.
 63  
  * </p>
 64  
  *
 65  
  * @since 1.3
 66  
  * @author Oliver Heger
 67  
  * @version $Id: SubnodeConfiguration.java 439648 2006-09-02 20:42:10Z oheger $
 68  
  */
 69  
 public class SubnodeConfiguration extends HierarchicalConfiguration
 70  
 {
 71  
     /**
 72  
      * The serial version UID.
 73  
      */
 74  
     private static final long serialVersionUID = 3105734147019386480L;
 75  
 
 76  
     /** Stores the parent configuration. */
 77  
     private HierarchicalConfiguration parent;
 78  
 
 79  
     /**
 80  
      * Creates a new instance of <code>SubnodeConfiguration</code> and
 81  
      * initializes it with the parent configuration and the new root node.
 82  
      *
 83  
      * @param parent the parent configuration
 84  
      * @param root the root node of this subnode configuration
 85  
      */
 86  
     public SubnodeConfiguration(HierarchicalConfiguration parent, ConfigurationNode root)
 87  190
     {
 88  190
         if (parent == null)
 89  
         {
 90  1
             throw new IllegalArgumentException(
 91  
                     "Parent configuration must not be null!");
 92  
         }
 93  189
         if (root == null)
 94  
         {
 95  1
             throw new IllegalArgumentException("Root node must not be null!");
 96  
         }
 97  
 
 98  188
         setRootNode(root);
 99  188
         this.parent = parent;
 100  188
         initFromParent(parent);
 101  188
     }
 102  
 
 103  
     /**
 104  
      * Returns the parent configuration of this subnode configuration.
 105  
      *
 106  
      * @return the parent configuration
 107  
      */
 108  
     public HierarchicalConfiguration getParent()
 109  
     {
 110  411
         return parent;
 111  
     }
 112  
 
 113  
     /**
 114  
      * Returns a hierarchical configuration object for the given sub node.
 115  
      * This implementation will ensure that the returned
 116  
      * <code>SubnodeConfiguration</code> object will have the same parent than
 117  
      * this object.
 118  
      *
 119  
      * @param node the sub node, for which the configuration is to be created
 120  
      * @return a hierarchical configuration for this sub node
 121  
      */
 122  
     protected SubnodeConfiguration createSubnodeConfiguration(ConfigurationNode node)
 123  
     {
 124  75
         return new SubnodeConfiguration(getParent(), node);
 125  
     }
 126  
 
 127  
     /**
 128  
      * Creates a new node. This task is delegated to the parent.
 129  
      *
 130  
      * @param name the node's name
 131  
      * @return the new node
 132  
      */
 133  
     protected Node createNode(String name)
 134  
     {
 135  4
         return getParent().createNode(name);
 136  
     }
 137  
 
 138  
     /**
 139  
      * Initializes this subnode configuration from the given parent
 140  
      * configuration. This method is called by the constructor. It will copy
 141  
      * many settings from the parent.
 142  
      *
 143  
      * @param parentConfig the parent configuration
 144  
      */
 145  
     protected void initFromParent(HierarchicalConfiguration parentConfig)
 146  
     {
 147  188
         setExpressionEngine(parentConfig.getExpressionEngine());
 148  188
         setListDelimiter(parentConfig.getListDelimiter());
 149  188
         setDelimiterParsingDisabled(parentConfig.isDelimiterParsingDisabled());
 150  188
         setThrowExceptionOnMissing(parentConfig.isThrowExceptionOnMissing());
 151  188
     }
 152  
 
 153  
     /**
 154  
      * Performs interpolation. This implementation will ask the parent
 155  
      * configuration to perform the interpolation so that variables can be
 156  
      * evaluated in the global context.
 157  
      *
 158  
      * @param value the value to be interpolated
 159  
      */
 160  
     protected Object interpolate(Object value)
 161  
     {
 162  288
         return getParent().interpolate(value);
 163  
     }
 164  
 }