Page (H2 Database Engine wt-1.0.1 API)

java.lang.Object
- org.h2.mvstore.Page

```
public class Page
extends Object
```
A page (a node or a leaf).
For b-tree nodes, the key at a given index is larger than the largest key of the child at the same index.
File format: page length (including length): int check value: short map id: varInt number of keys: varInt type: byte (0: leaf, 1: node; +2: compressed) compressed: bytes saved (varInt) keys leaf: values (one for each key) node: children (1 more than keys)

嵌套类概要

嵌套类
限定符和类型	类和说明
`static class`	`Page.PageChildren` Contains information about which other pages are referenced (directly or indirectly) by the given page.
`static class`	`Page.PageReference` A pointer to a page, either in-memory or using a page position.

字段概要

字段
限定符和类型字段和说明

static Object[] EMPTY_OBJECT_ARRAY
An empty object array.

字段
限定符和类型	字段和说明
`static Object[]`	`EMPTY_OBJECT_ARRAY` An empty object array.

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法和说明
`int`	`binarySearch(Object key)` Search the key in this page using a binary search.
`Page`	`copy(long version)` Create a copy of this page.
`static Page`	`create(MVMap<?,?> map, long version, Object[] keys, Object[] values, Page.PageReference[] children, long totalCount, int memory)` Create a new page.
`static Page`	`create(MVMap<?,?> map, long version, Page source)` Create a copy of a page.
`boolean`	`equals(Object other)`
`Page`	`getChildPage(int index)` Get the child page at the given index.
`long`	`getChildPagePos(int index)` Get the position of the child.
`Object`	`getKey(int index)` Get the key at the given index.
`int`	`getKeyCount()` Get the number of keys in this page.
`int`	`getMemory()`
`long`	`getPos()` Get the position of the page
`int`	`getRawChildPageCount()`
`long`	`getTotalCount()` Get the total number of key-value pairs, including child pages.
`Object`	`getValue(int index)` Get the value at the given index.
`int`	`hashCode()`
`void`	`insertLeaf(int index, Object key, Object value)` Insert a key-value pair into this leaf.
`void`	`insertNode(int index, Object key, Page childPage)` Insert a child page into this node.
`boolean`	`isLeaf()` Check whether this is a leaf page.
`void`	`remove(int index)` Remove the key and value (or child) at the given index.
`void`	`removePage()` Remove the page.
`void`	`setChild(int index, Page c)` Replace the child page.
`void`	`setKey(int index, Object key)` Replace the key at an index in this page.
`Object`	`setValue(int index, Object value)` Replace the value at an index in this page.
`String`	`toString()`

从类继承的方法 java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - EMPTY_OBJECT_ARRAY
```
public static final Object[] EMPTY_OBJECT_ARRAY
```
    An empty object array.
- 方法详细资料
  - create
```
public static Page create(MVMap<?,?> map,
                          long version,
                          Object[] keys,
                          Object[] values,
                          Page.PageReference[] children,
                          long totalCount,
                          int memory)
```
    Create a new page. The arrays are not cloned.
    
    参数:
    
    map - the map
    
    version - the version
    
    keys - the keys
    
    values - the values
    
    children - the child page positions
    
    totalCount - the total number of keys
    
    memory - the memory used in bytes
    
    返回:
    
    the page
  - create
```
public static Page create(MVMap<?,?> map,
                          long version,
                          Page source)
```
    Create a copy of a page.
    
    参数:
    
    map - the map
    
    version - the version
    
    source - the source page
    
    返回:
    
    the page
  - getKey
```
public Object getKey(int index)
```
    Get the key at the given index.
    
    参数:
    
    index - the index
    
    返回:
    
    the key
  - getChildPage
```
public Page getChildPage(int index)
```
    Get the child page at the given index.
    
    参数:
    
    index - the index
    
    返回:
    
    the child page
  - getChildPagePos
```
public long getChildPagePos(int index)
```
    Get the position of the child.
    
    参数:
    
    index - the index
    
    返回:
    
    the position
  - getValue
```
public Object getValue(int index)
```
    Get the value at the given index.
    
    参数:
    
    index - the index
    
    返回:
    
    the value
  - getKeyCount
```
public int getKeyCount()
```
    Get the number of keys in this page.
    
    返回:
    
    the number of keys
  - isLeaf
```
public boolean isLeaf()
```
    Check whether this is a leaf page.
    
    返回:
    
    true if it is a leaf
  - getPos
```
public long getPos()
```
    Get the position of the page
    
    返回:
    
    the position
  - toString
```
public String toString()
```
    覆盖:
    
    toString 在类中 Object
  - copy
```
public Page copy(long version)
```
    Create a copy of this page.
    
    参数:
    
    version - the new version
    
    返回:
    
    a page with the given version
  - binarySearch
```
public int binarySearch(Object key)
```
    Search the key in this page using a binary search. Instead of always starting the search in the middle, the last found index is cached.
    If the key was found, the returned value is the index in the key array. If not found, the returned value is negative, where -1 means the provided key is smaller than any keys in this page. See also Arrays.binarySearch.
    
    参数:
    
    key - the key
    
    返回:
    
    the value or null
  - getTotalCount
```
public long getTotalCount()
```
    Get the total number of key-value pairs, including child pages.
    
    返回:
    
    the number of key-value pairs
  - setChild
```
public void setChild(int index,
                     Page c)
```
    Replace the child page.
    
    参数:
    
    index - the index
    
    c - the new child page
  - setKey
```
public void setKey(int index,
                   Object key)
```
    Replace the key at an index in this page.
    
    参数:
    
    index - the index
    
    key - the new key
  - setValue
```
public Object setValue(int index,
                       Object value)
```
    Replace the value at an index in this page.
    
    参数:
    
    index - the index
    
    value - the new value
    
    返回:
    
    the old value
  - insertLeaf
```
public void insertLeaf(int index,
                       Object key,
                       Object value)
```
    Insert a key-value pair into this leaf.
    
    参数:
    
    index - the index
    
    key - the key
    
    value - the value
  - insertNode
```
public void insertNode(int index,
                       Object key,
                       Page childPage)
```
    Insert a child page into this node.
    
    参数:
    
    index - the index
    
    key - the key
    
    childPage - the child page
  - remove
```
public void remove(int index)
```
    Remove the key and value (or child) at the given index.
    
    参数:
    
    index - the index
  - getRawChildPageCount
```
public int getRawChildPageCount()
```
  - equals
```
public boolean equals(Object other)
```
    覆盖:
    
    equals 在类中 Object
  - hashCode
```
public int hashCode()
```
    覆盖:
    
    hashCode 在类中 Object
  - getMemory
```
public int getMemory()
```
  - removePage
```
public void removePage()
```
    Remove the page.

类 Page

嵌套类概要

字段概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

EMPTY_OBJECT_ARRAY

方法详细资料

create

create

getKey

getChildPage

getChildPagePos

getValue

getKeyCount

isLeaf

getPos

toString

copy

binarySearch

getTotalCount

setChild

setKey

setValue

insertLeaf

insertNode

remove

getRawChildPageCount

equals

hashCode

getMemory

removePage