com.allanbank.mongodb.bson.element

Class AbstractElement

java.lang.Object

com.allanbank.mongodb.bson.element.AbstractElement

All Implemented Interfaces:

Element, ElementAssignable, Serializable, Comparable<Element>

Direct Known Subclasses:

AbstractBuilder.BuilderElement, ArrayElement, BinaryElement, BooleanElement, DBPointerElement, DocumentElement, DoubleElement, IntegerElement, JavaScriptElement, LongElement, MaxKeyElement, MinKeyElement, MongoTimestampElement, NullElement, ObjectIdElement, RegularExpressionElement, StringElement, SymbolElement, TimestampElement

public abstract class AbstractElement
extends Object
implements Element

A base class for the basic BSON types.

See Also:

Serialized Form

API Notice:

This class is part of the driver's API. Public and protected members will be deprecated for at least 1 non-bugfix release (version numbers are <major>.<minor>.<bugfix>) before being removed or modified.

Copyright ©:

2011-2014, Allanbank Consulting, Inc., All Rights Reserved

Field Summary

Fields

Modifier and Type	Field and Description
protected static Class<Element>	ELEMENT_TYPE The base type (interface) for all elements.

Constructor Summary

Constructors

Constructor and Description
AbstractElement(String name, long size) Constructs a new AbstractElement.

Method Summary

Methods

Modifier and Type	Method and Description
Element	asElement() Converts the object into an Element.
int	compareTo(Element otherElement)
boolean	equals(Object object) Determines if the passed object is of this same type as this object and if so that its fields are equal.
<E extends Element> List<E>	find(Class<E> clazz, String... nameRegexs) Returns the elements matching the path of regular expressions.
List<Element>	find(String... nameRegexs) Returns the elements matching the path of regular expressions.
<E extends Element> E	findFirst(Class<E> clazz, String... nameRegexs) Returns the first element matching the path of regular expressions.
Element	findFirst(String... nameRegexs) Returns the first element matching the path of regular expressions.
String	getName() Returns the name for the BSON type.
String	getValueAsString() Returns the value for BSON element as a Java String.
int	hashCode() Computes a reasonable hash code.
protected boolean	nullSafeEquals(Object rhs, Object lhs) Does a null safe equals comparison.
long	size() Returns the number of bytes that are used to encode the element.
String	toString() String form of the object.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.allanbank.mongodb.bson.Element

accept, getType, getValueAsObject, withName

Field Detail

ELEMENT_TYPE

protected static final Class<Element> ELEMENT_TYPE

The base type (interface) for all elements.

Constructor Detail

AbstractElement

public AbstractElement(String name,
               long size)
                throws IllegalArgumentException

Constructs a new AbstractElement.

Parameters:

name - The name for the BSON type.

size - The size of the element when encoded in bytes.

Throws:

IllegalArgumentException - If the name is null.

Method Detail

asElement

public Element asElement()

Converts the object into an Element.

Returns this element.

Specified by:

asElement in interface ElementAssignable

Returns:

The object as an Element.

compareTo

public int compareTo(Element otherElement)

Overridden to compare the elements based on the tuple (name, type, value).

Overridden to compare the elements based on the tuple (name, type). Derived classes are responsible for the value portion of the full comparison.

Specified by:

compareTo in interface Element

Specified by:

compareTo in interface Comparable<Element>

equals

public boolean equals(Object object)

Determines if the passed object is of this same type as this object and if so that its fields are equal.

Overrides:

equals in class Object

Parameters:

object - The object to compare to.

See Also:

Object.equals(java.lang.Object)

find

public <E extends Element> List<E> find(Class<E> clazz,
                               String... nameRegexs)

Returns the elements matching the path of regular expressions.

Returns a singleton list if the nameRegexs is empty and this element's type is assignable to E. An empty list otherwise.

Specified by:

find in interface Element

Type Parameters:

E - The type of element to match.

Parameters:

clazz - The class of elements to match.

nameRegexs - The path of regular expressions.

Returns:

The elements matching the path of regular expressions.

See Also:

Element.find(java.lang.Class<E>, java.lang.String...)

find

public List<Element> find(String... nameRegexs)

Returns the elements matching the path of regular expressions.

Returns a singleton list if the nameRegexs is empty. An empty list otherwise.

Specified by:

find in interface Element

Parameters:

nameRegexs - The path of regular expressions.

Returns:

The elements matching the path of regular expressions.

See Also:

Element.find(java.lang.Class<E>, java.lang.String...)

findFirst

public <E extends Element> E findFirst(Class<E> clazz,
                              String... nameRegexs)

Returns the first element matching the path of regular expressions.

Returns a this if the nameRegexs is empty and this element's type is assignable to E. An empty list otherwise.

Specified by:

findFirst in interface Element

Type Parameters:

E - The type of element to match.

Parameters:

clazz - The class of element to match.

nameRegexs - The path of regular expressions.

Returns:

The first element matching the path of regular expressions.

See Also:

Element.findFirst(java.lang.Class<E>, java.lang.String...)

findFirst

public Element findFirst(String... nameRegexs)

Returns the first element matching the path of regular expressions.

Searches this sub-elements for matching elements on the path and are of the right type.

Specified by:

findFirst in interface Element

Parameters:

nameRegexs - The path of regular expressions.

Returns:

The first element matching the path of regular expressions.

See Also:

Element.findFirst(java.lang.Class<E>, java.lang.String...)

getName

public String getName()

Returns the name for the BSON type.

Specified by:

getName in interface Element

Returns:

The name for the BSON type.

getValueAsString

public String getValueAsString()

Returns the value for BSON element as a Java String. Automatic conversion from the string value back to an Element is not provided.

Generally the string returned will be the expected value. As an example for a LongElement with the value 101 the returned string will be "101". In those cases where there is not canonical form for the value (e.g., a TimestampElement the returned string will match the value when converted to JSON by the JsonSerializationVisitor. For a TimestampElement that is a string of the form "ISODate('1970-01-01T00:00:00.000+0000')".

Uses the JsonSerializationVisitor to encode the value. In some cases it will be more efficient to override this method with a more straight forward conversion.

Specified by:

getValueAsString in interface Element

Returns:

The value for BSON element as a String.

hashCode

public int hashCode()

Computes a reasonable hash code.

Overrides:

hashCode in class Object

Returns:

The hash code value.

size

public long size()

Returns the number of bytes that are used to encode the element.

Specified by:

size in interface Element

Returns:

The bytes that are used to encode the element.

toString

public String toString()

String form of the object.

Overrides:

toString in class Object

Returns:

A human readable form of the object.

See Also:

Object.toString()

nullSafeEquals

protected boolean nullSafeEquals(Object rhs,
                     Object lhs)

Does a null safe equals comparison.

Parameters:

rhs - The right-hand-side of the comparison.

lhs - The left-hand-side of the comparison.

Returns:

True if the rhs equals the lhs. Note: nullSafeEquals(null, null) returns true.