MergeCombiner (Apache Commons Configuration 1.10 API)

java.lang.Object
- org.apache.commons.configuration.tree.NodeCombiner
- - org.apache.commons.configuration.tree.MergeCombiner

```
public class MergeCombiner
extends NodeCombiner
```
A specialized implementation of the NodeCombiner interface that performs a merge from two passed in node hierarchies.

This combiner performs the merge using a few rules:
1. Nodes can be merged when attributes that appear in both have the same value.
2. Only a single node in the second file is considered a match to the node in the first file.
3. Attributes in nodes that match are merged.
4. Nodes in both files that do not match are added to the result.
Since:

1.7

Version:

$Id: MergeCombiner.java 1301991 2012-03-17 20:18:02Z sebb $

Author:

Commons Configuration team

Field Summary
- Fields inherited from class org.apache.commons.configuration.tree.NodeCombiner
  listNodes

Constructor Summary

Constructors
Constructor and Description

MergeCombiner()

Constructors
Constructor and Description
`MergeCombiner()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`addAttributes(ViewNode result, ConfigurationNode node1, ConfigurationNode node2)` Handles the attributes during a combination process.
`protected ConfigurationNode`	`canCombine(ConfigurationNode node1, ConfigurationNode node2, ConfigurationNode child, List<ConfigurationNode> children2)` Tests if the first node can be combined with the second node.
`ConfigurationNode`	`combine(ConfigurationNode node1, ConfigurationNode node2)` Combines the given nodes to a new union node.

Methods inherited from class org.apache.commons.configuration.tree.NodeCombiner
addListNode, createViewNode, getListNodes, isListNode

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MergeCombiner
```
public MergeCombiner()
```
- Method Detail
  - combine
```
public ConfigurationNode combine(ConfigurationNode node1,
                        ConfigurationNode node2)
```
    Combines the given nodes to a new union node.
    
    Specified by:
    
    combine in class NodeCombiner
    
    Parameters:
    node1 - the first source node
    node2 - the second source node
    
    Returns:
    the union node
  - addAttributes
```
protected void addAttributes(ViewNode result,
                 ConfigurationNode node1,
                 ConfigurationNode node2)
```
    Handles the attributes during a combination process. First all attributes of the first node will be added to the result. Then all attributes of the second node, which are not contained in the first node, will also be added.
    
    Parameters:
    result - the resulting node
    node1 - the first node
    node2 - the second node
  - canCombine
```
protected ConfigurationNode canCombine(ConfigurationNode node1,
                           ConfigurationNode node2,
                           ConfigurationNode child,
                           List<ConfigurationNode> children2)
```
    Tests if the first node can be combined with the second node. A node can only be combined if its attributes are all present in the second node and they all have the same value.
    
    Parameters:
    node1 - the first node
    node2 - the second node
    child - the child node (of the first node)
    
    Returns:
    a child of the second node, with which a combination is possible

Class MergeCombiner

Field Summary

Fields inherited from class org.apache.commons.configuration.tree.NodeCombiner

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.configuration.tree.NodeCombiner

Methods inherited from class java.lang.Object

Constructor Detail

MergeCombiner

Method Detail

combine

addAttributes

canCombine