SizeOfVisitor (mongodb-async-driver 1.2.2 API)

java.lang.Object
- com.allanbank.mongodb.bson.io.SizeOfVisitor

All Implemented Interfaces:

Visitor
```
public class SizeOfVisitor
extends Object
implements Visitor
```
A visitor to determine the size of the documents it visits. Intermediate document sizes are cached for faster access later.
Caching is accomplished via a simple singly linked list of the cached documents. This works since the document will be written in the same in-order traversal of the document tree that this visitor follows. As each level of the tree is written this visitor should have rewind() called to set the size back to zero and also remove the head from the document cache list. If the next document written is the expected in-order traversal there is a cache hit and the size is simply read from the cache's head node. Rinse, repeat.

A custom list node type is used instead of a generic linked list to remove the overhead of extra object allocations for the node and the value.

API Warning:

This class is NOT part of the drivers API. This class may be mutated in incompatible ways between any two releases of the driver.

Copyright ©:

2011-2013, Allanbank Consulting, Inc., All Rights Reserved

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`SizeOfVisitor.CachedSizeNode` CachedSizeNode provides a node in a singly linked list that forms the cache for the sizes of lists of elements.

Field Summary

Fields
Modifier and Type Field and Description

static Charset UTF8
UTF-8 Character set for encoding strings.

Fields
Modifier and Type	Field and Description
`static Charset`	`UTF8` UTF-8 Character set for encoding strings.

Constructor Summary

Constructors
Constructor and Description

SizeOfVisitor()
Creates a new SizeOfVisitor.

Constructors
Constructor and Description
`SizeOfVisitor()` Creates a new SizeOfVisitor.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`computeCStringSize(String string)` Returns the visitor's output buffer.
`int`	`computeStringSize(String string)` Returns the visitor's output buffer.
`int`	`getSize()` Return the current Size of the written document.
`void`	`reset()` Resets the size to zero and clears the cached documents.
`void`	`rewind()` Resets the size to zero but does not clear the cached documents.
`int`	`utf8Size(String string)` Computes the size of the encoded UTF8 String based on the table below.
`void`	`visit(List<Element> elements)` Visit the root document.
`void`	`visitArray(String name, List<Element> elements)` Visits an array of elements.
`void`	`visitBinary(String name, byte subType, byte[] data)` Visits a binary element.
`void`	`visitBoolean(String name, boolean value)` Visits a boolean element.
`void`	`visitDBPointer(String name, String databaseName, String collectionName, ObjectId id)` Visits a deprecated DBPointer element.
`void`	`visitDocument(String name, List<Element> elements)` Visits a sub-document element.
`void`	`visitDouble(String name, double value)` Visits a double element.
`void`	`visitInteger(String name, int value)` Visits a integer (32-bit signed) element.
`void`	`visitJavaScript(String name, String code)` Visits a JavaScript element.
`void`	`visitJavaScript(String name, String code, Document scope)` Visits a JavaScript with Scope element.
`void`	`visitLong(String name, long value)` Visits a long (64-bit signed) element.
`void`	`visitMaxKey(String name)` Visits a minimum key value element.
`void`	`visitMinKey(String name)` Visits a minimum key value element.
`void`	`visitMongoTimestamp(String name, long value)` Visits a MongoDB Timestamp element.
`void`	`visitNull(String name)` Visits a `null` valued element.
`void`	`visitObjectId(String name, ObjectId id)` Visits an ObjectId element.
`void`	`visitRegularExpression(String name, String pattern, String options)` Visits a regular expression element.
`void`	`visitString(String name, String value)` Visits a string element.
`void`	`visitSymbol(String name, String symbol)` Visits a symbol element.
`void`	`visitTimestamp(String name, long timestamp)` Visits a timestamp element.

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

- Field Detail
  - UTF8
```
public static final Charset UTF8
```
    UTF-8 Character set for encoding strings.
- Constructor Detail
  - SizeOfVisitor
```
public SizeOfVisitor()
```
    Creates a new SizeOfVisitor.
- Method Detail
  - computeCStringSize
```
public int computeCStringSize(String string)
```
    Returns the visitor's output buffer.
    
    Parameters:
    string - The 'C' string to determine the size of.
    
    Returns:
    The visitor's output buffer.
  - computeStringSize
```
public int computeStringSize(String string)
```
    Returns the visitor's output buffer.
    
    Parameters:
    string - The 'UTF8' string to determine the size of.
    
    Returns:
    The visitor's output buffer.
  - getSize
```
public int getSize()
```
    Return the current Size of the written document.
    
    Returns:
    The current size of the encoded document.
  - reset
```
public void reset()
```
    Resets the size to zero and clears the cached documents. Use rewind() to just set the size to zero and not clear the cached documents.
  - rewind
```
public void rewind()
```
    Resets the size to zero but does not clear the cached documents. Use reset() to set the size to zero and clear the cached documents.
  - utf8Size
```
public int utf8Size(String string)
```
    Computes the size of the encoded UTF8 String based on the table below.
```
 #    Code Points      Bytes
 1    U+0000..U+007F   1
 
 2    U+0080..U+07FF   2
 
 3    U+0800..U+0FFF   3
      U+1000..U+FFFF
 
 4   U+10000..U+3FFFF  4
     U+40000..U+FFFFF  4
    U+100000..U10FFFF  4
 
```
    Parameters:
    string - The string to determine the length of.
    
    Returns:
    The length of the string encoded as UTF8.
  - visit
```
public void visit(List<Element> elements)
```
    Visit the root document.
    Implementations of Document may see a significant performance enhancement if they ensure that the list of elements is the same list. (Identify check instead of Object.equals(Object).
    
    Specified by:
    
    visit in interface Visitor
    
    Parameters:
    elements - The sub elements of the document.
  - visitArray
```
public void visitArray(String name,
              List<Element> elements)
```
    Visits an array of elements.
    The ArrayElement implementation ensures that the list of elements is always the same list. Visitors may use this fact to cache intermediate results.
    
    Specified by:
    
    visitArray in interface Visitor
    
    Parameters:
    name - The name of the element.
    elements - The elements in the array.
  - visitBinary
```
public void visitBinary(String name,
               byte subType,
               byte[] data)
```
    Visits a binary element.
    
    Specified by:
    
    visitBinary in interface Visitor
    
    Parameters:
    name - The name of the element.
    subType - The binary data sub type.
    data - The binary data.
  - visitBoolean
```
public void visitBoolean(String name,
                boolean value)
```
    Visits a boolean element.
    
    Specified by:
    
    visitBoolean in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The boolean value.
  - visitDBPointer
```
public void visitDBPointer(String name,
                  String databaseName,
                  String collectionName,
                  ObjectId id)
```
    Visits a deprecated DBPointer element.
    
    Specified by:
    
    visitDBPointer in interface Visitor
    
    Parameters:
    name - The name of the element.
    databaseName - The name of the database containing the document.
    collectionName - The name of the collection containing the document.
    id - The id for the document.
  - visitDocument
```
public void visitDocument(String name,
                 List<Element> elements)
```
    Visits a sub-document element.
    The DocumentElement implementation ensures that the list of elements is always the same list. Visitors may use this fact to cache intermediate results.
    
    Specified by:
    
    visitDocument in interface Visitor
    
    Parameters:
    name - The name of the element.
    elements - The sub elements of the document.
  - visitDouble
```
public void visitDouble(String name,
               double value)
```
    Visits a double element.
    
    Specified by:
    
    visitDouble in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The double value.
  - visitInteger
```
public void visitInteger(String name,
                int value)
```
    Visits a integer (32-bit signed) element.
    
    Specified by:
    
    visitInteger in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The integer value.
  - visitJavaScript
```
public void visitJavaScript(String name,
                   String code)
```
    Visits a JavaScript element.
    
    Specified by:
    
    visitJavaScript in interface Visitor
    
    Parameters:
    name - The name of the element.
    code - The java script code.
  - visitJavaScript
```
public void visitJavaScript(String name,
                   String code,
                   Document scope)
```
    Visits a JavaScript with Scope element.
    
    Specified by:
    
    visitJavaScript in interface Visitor
    
    Parameters:
    name - The name of the element.
    code - The java script code.
    scope - The scope for the JacaScript code.
  - visitLong
```
public void visitLong(String name,
             long value)
```
    Visits a long (64-bit signed) element.
    
    Specified by:
    
    visitLong in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The long value.
  - visitMaxKey
```
public void visitMaxKey(String name)
```
    Visits a minimum key value element. Used as an absolute upper bounds.
    
    Specified by:
    
    visitMaxKey in interface Visitor
    
    Parameters:
    name - The name of the element.
  - visitMinKey
```
public void visitMinKey(String name)
```
    Visits a minimum key value element. Used as an absolute lower bounds.
    
    Specified by:
    
    visitMinKey in interface Visitor
    
    Parameters:
    name - The name of the element.
  - visitMongoTimestamp
```
public void visitMongoTimestamp(String name,
                       long value)
```
    Visits a MongoDB Timestamp element.
    
    Specified by:
    
    visitMongoTimestamp in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The mongoDB timstamp value.
  - visitNull
```
public void visitNull(String name)
```
    Visits a null valued element.
    
    Specified by:
    
    visitNull in interface Visitor
    
    Parameters:
    name - The name of the element.
  - visitObjectId
```
public void visitObjectId(String name,
                 ObjectId id)
```
    Visits an ObjectId element.
    
    Specified by:
    
    visitObjectId in interface Visitor
    
    Parameters:
    name - The name of the element.
    id - The object id.
  - visitRegularExpression
```
public void visitRegularExpression(String name,
                          String pattern,
                          String options)
```
    Visits a regular expression element.
    
    Specified by:
    
    visitRegularExpression in interface Visitor
    
    Parameters:
    name - The name of the element.
    pattern - The pattern for the regular expression.
    options - The regular expression options. See the BSON specification for details.
  - visitString
```
public void visitString(String name,
               String value)
```
    Visits a string element.
    
    Specified by:
    
    visitString in interface Visitor
    
    Parameters:
    name - The name of the element.
    value - The string value.
  - visitSymbol
```
public void visitSymbol(String name,
               String symbol)
```
    Visits a symbol element.
    
    Specified by:
    
    visitSymbol in interface Visitor
    
    Parameters:
    name - The name of the element.
    symbol - The symbol value.
  - visitTimestamp
```
public void visitTimestamp(String name,
                  long timestamp)
```
    Visits a timestamp element. The timestamp is the number of milliseconds since the Unix epoch.
    
    Specified by:
    
    visitTimestamp in interface Visitor
    
    Parameters:
    name - The name of the element.
    timestamp - The number of milliseconds since the Unix epoch.

Class SizeOfVisitor

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UTF8

Constructor Detail

SizeOfVisitor

Method Detail

computeCStringSize

computeStringSize

getSize

reset

rewind

utf8Size

visit

visitArray

visitBinary

visitBoolean

visitDBPointer

visitDocument

visitDouble

visitInteger

visitJavaScript

visitJavaScript

visitLong

visitMaxKey

visitMinKey

visitMongoTimestamp

visitNull

visitObjectId

visitRegularExpression

visitString

visitSymbol

visitTimestamp