java.lang.Object
- org.apache.jackrabbit.oak.index.indexer.document.tree.store.TreeSession

```
public class TreeSession
extends Object
```
A session that allows reading and writing keys and values in a tree store.

Field Summary

Fields
Modifier and Type Field Description

static String CACHE_SIZE_MB

static String LEAF_PREFIX

static String ROOT_NAME

Constructor Summary

Constructors
Constructor Description

TreeSession()

TreeSession(Store store)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`checkpoint()`	Make the current tree read-only and switch to a new root.
`Iterable<Map.Entry<String,String>>`	`entrySet()`
`void`	`flush()`	Flush all changes to storage.
`String`	`get(String key)`	Get an entry.
`String`	`getApproximateMedianKey(String low, String high, Random r)`
`static String`	`getFileNameRegex()`
`long`	`getFileReadCount()`	Get the number of files read from the cache or storage.
`String`	`getInfo()`
`String`	`getMaxKey()`
`int`	`getMaxRoots()`
`String`	`getMinKey()`
`int`	`getRootCount()`	Get the number of roots.
`void`	`init()`	Initialize the storage, creating a new root if needed.
`Iterator<Map.Entry<String,String>>`	`iterator()`	Get all entries.
`Iterator<Map.Entry<String,String>>`	`iterator(String largerThan)`	Get all entries.
`Iterable<String>`	`keys()`	Return all keys in sorted order.
`Iterable<String>`	`keys(String largerThan)`	Return all keys in sorted order.
`void`	`mergeRoots(int max)`	Merge a number of roots.
`void`	`put(String key, String value)`	Put a value.
`void`	`runGC()`
`void`	`setMaxRoots(int maxRoots)`	Set the maximum number of roots.

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

- Field Detail
  - CACHE_SIZE_MB
```
public static final String CACHE_SIZE_MB
```
    See Also:
    
    Constant Field Values
  - ROOT_NAME
```
public static final String ROOT_NAME
```
    See Also:
    
    Constant Field Values
  - LEAF_PREFIX
```
public static final String LEAF_PREFIX
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - TreeSession
```
public TreeSession()
```
  - TreeSession
```
public TreeSession(Store store)
```
- Method Detail
  - getFileNameRegex
```
public static String getFileNameRegex()
```
  - setMaxRoots
```
public void setMaxRoots(int maxRoots)
```
    Set the maximum number of roots.
    
    Parameters:
    
    maxRoots - the new value
  - getMaxRoots
```
public int getMaxRoots()
```
  - getFileReadCount
```
public long getFileReadCount()
```
    Get the number of files read from the cache or storage.
    
    Returns:
    
    the result
  - init
```
public void init()
```
    Initialize the storage, creating a new root if needed.
  - get
```
public String get(String key)
```
    Get an entry.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value, or null
  - put
```
public void put(String key,
                String value)
```
    Put a value. To remove an entry, the value needs to be null.
    
    Parameters:
    
    key - the key
    
    value - the value
  - mergeRoots
```
public void mergeRoots(int max)
```
    Merge a number of roots. Merging will create a new root, which contains the data of the previous roots. If there are less roots, this method returns without merging.
    
    Parameters:
    
    max - the number of roots to merge (Integer.MAX_VALUE for all)
  - getRootCount
```
public int getRootCount()
```
    Get the number of roots.
    
    Returns:
    
    the number of roots
  - checkpoint
```
public void checkpoint()
```
    Make the current tree read-only and switch to a new root. If there are already too many roots, then they will be merged. All changes are flushed to storage.
  - flush
```
public void flush()
```
    Flush all changes to storage.
  - iterator
```
public Iterator<Map.Entry<String,String>> iterator()
```
    Get all entries. Do not add or move entries while iterating.
    
    Returns:
    
    the result
  - iterator
```
public Iterator<Map.Entry<String,String>> iterator(String largerThan)
```
    Get all entries. Do not add or move entries while iterating.
    
    Parameters:
    
    largerThan - all returned keys are larger than this; null to start at the beginning
    
    Returns:
    
    the result
  - entrySet
```
public Iterable<Map.Entry<String,String>> entrySet()
```
  - keys
```
public Iterable<String> keys()
```
    Return all keys in sorted order. Roots don't need to be merged.
    
    Returns:
    
    all keys
  - keys
```
public Iterable<String> keys(String largerThan)
```
    Return all keys in sorted order.
    
    Parameters:
    
    largerThan - all returned keys are larger than this; null to start at the beginning
    
    Returns:
    
    the keys
  - runGC
```
public void runGC()
```
  - getInfo
```
public String getInfo()
```
  - getMinKey
```
public String getMinKey()
```
  - getMaxKey
```
public String getMaxKey()
```
  - getApproximateMedianKey
```
public String getApproximateMedianKey(String low,
                                      String high,
                                      Random r)
```

Modifier and Type	Field	Description
`static String`	`CACHE_SIZE_MB`
`static String`	`LEAF_PREFIX`
`static String`	`ROOT_NAME`

Constructors
Constructor	Description
`TreeSession()`
`TreeSession(Store store)`

Class TreeSession

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CACHE_SIZE_MB

ROOT_NAME

LEAF_PREFIX

Constructor Detail

TreeSession

TreeSession

Method Detail

getFileNameRegex

setMaxRoots

getMaxRoots

getFileReadCount

init

get

put

mergeRoots

getRootCount

checkpoint

flush

iterator

iterator

entrySet

keys

keys

runGC

getInfo

getMinKey

getMaxKey

getApproximateMedianKey