Class DotName
- All Implemented Interfaces:
Comparable<DotName>
DotName
represents a dot separated name, typically a Java package or a Java class.
It has two possible variants. A simple wrapper based variant allows for fast construction
(it simply wraps the specified name string). Whereas, a componentized variant represents
one or more String
components that, when combined with a dot character, assemble the
full name. The intention of the componentized variant is that the String
components
can be reused to offer memory efficiency. This reuse is common in Java where packages
and classes follow a tree structure.
Both the simple and componentized variants are considered semantically equivalent if they
refer to the same logical name. More specifically, the equals
and hashCode
methods return the same values for the same semantic name regardless of the variant used.
Which variant to use when depends on the specific performance and overhead objectives
of the specific use pattern.
Simple names are cheap to construct (just an additional wrapper object), so are ideal for
temporary use, like looking for an entry in a Map
. Componentized names however require
that they be split in advance, and so require some additional time to construct. However, the memory
benefits of reusing component strings make them desirable when stored in a longer term area
such as in a Java data structure.
- Author:
- Jason T. Greene
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Field Summary
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Method Summary
Modifier and TypeMethodDescriptionint
Compares aDotName
to anotherDotName
and returns whether thisDotName
is lesser than, greater than, or equal to the specified DotName.static DotName
createComponentized
(DotName prefix, String localName) Constructs a componentizedDotName
.static DotName
createComponentized
(DotName prefix, String localName, boolean innerClass) Constructs a componentizedDotName
.static DotName
createSimple
(Class<?> clazz) Constructs a simpleDotName
which stores the name of given class in its entirety.static DotName
createSimple
(String name) Constructs a simpleDotName
which stores the string in its entirety.boolean
Compares aDotName
to anotherDotName
and returnstrue
if they represent the same underlying semantic name.int
hashCode()
Returns a hash code which is based on the semantic representation of thisDotName
.boolean
Returns whether thisDotName
is a componentized variant.boolean
isInner()
Returns whether the local portion of a componentizedDotName
is separated by an inner class style delimiter ('$'
).local()
Returns the local portion of thisDotName
.Returns the package portion of thisDotName
.Returns the package portion of thisDotName
.prefix()
Returns the parent prefix for thisDotName
ornull
if there is none.toString()
Returns the regular binary class name.toString
(char delim) Returns the regular binary class name wheredelim
is used as a package separator.Returns the portion of thisDotName
that does not contain a package prefix.
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Field Details
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OBJECT_NAME
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ENUM_NAME
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RECORD_NAME
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STRING_NAME
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Method Details
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createSimple
Constructs a simpleDotName
which stores the string in its entirety. This variant is ideal for temporary usage, such as looking up an entry in aMap
or an index.- Parameters:
name
- a fully qualified name (with dots); must not benull
- Returns:
- a simple
DotName
that wraps givenname
; nevernull
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createSimple
Constructs a simpleDotName
which stores the name of given class in its entirety. This variant is ideal for temporary usage, such as looking up an entry in aMap
or an index.This method is a shortcut for
DotName.createSimple(clazz.getName())
.- Parameters:
clazz
- a class whose fully qualified name is returned; must not benull
- Returns:
- a simple
DotName
that wraps the name of givenclazz
; nevernull
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createComponentized
Constructs a componentizedDotName
. SuchDotName
refers to a parent prefix (ornull
if there is no further prefix) in addition to a local name that has no dot separator. The fully qualified name thisDotName
represents is constructed by recursing all parent prefixes and joining all local names with the'.'
character.- Parameters:
prefix
- anotherDotName
that is the portion of the final name to the left oflocalName
; may benull
if there is no prefixlocalName
- the local portion of this name; must not benull
and must not contain'.'
- Returns:
- a componentized
DotName
; nevernull
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createComponentized
Constructs a componentizedDotName
. SuchDotName
refers to a parent prefix (ornull
if there is no further prefix) in addition to a local name that has no dot separator. The fully qualified name thisDotName
represents is constructed by recursing all parent prefixes and joining all local names with the'.'
character.- Parameters:
prefix
- anotherDotName
that is the portion of the final name to the left oflocalName
; may benull
if there is no prefixlocalName
- the local portion of this name; must not benull
and must not contain'.'
innerClass
- whether thelocalName
is an inner class style name, which is joined to the prefix using'$'
instead of'.'
- Returns:
- a componentized
DotName
; nevernull
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prefix
Returns the parent prefix for thisDotName
ornull
if there is none. SimpleDotName
variants never have a prefix.- Returns:
- the parent prefix for this
DotName
; may benull
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local
Returns the local portion of thisDotName
. In simple variants, the entire fully qualified string is returned. In componentized variants, just the rightmost portion not including a separator (either'.'
or'$'
) is returned.Use
withoutPackagePrefix()
instead of this method if the desired value is the part of the string (including'$'
signs if present) after the rightmost'.'
delimiter.- Returns:
- the local portion of this
DotName
; nevernull
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withoutPackagePrefix
Returns the portion of thisDotName
that does not contain a package prefix. In the case of an inner class syntax name, the'$'
portion is included in the return value.- Returns:
- the portion of the fully qualified name that does not include a package name
- Since:
- 2.1.1
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packagePrefix
Returns the package portion of thisDotName
.- Returns:
- the package name or
null
if thisDotName
has no package prefix - Since:
- 2.4
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packagePrefixName
Returns the package portion of thisDotName
. This is aDotName
-returning variant ofpackagePrefix()
.- Returns:
- the package name or
null
if thisDotName
has no package prefix - Since:
- 3.0
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isComponentized
public boolean isComponentized()Returns whether thisDotName
is a componentized variant.- Returns:
true
if it is componentized,false
if it is a simpleDotName
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isInner
public boolean isInner()Returns whether the local portion of a componentizedDotName
is separated by an inner class style delimiter ('$'
). The result is undefined when thisDotName
is not componentized.This should not be used to test whether the name truly refers to an inner class, only that the dollar sign delimits the value. Java class names are allowed to contain
'$'
signs, so the local value could simply be a fragment of a class name, and not an actual inner class. The correct way to determine whether a name refers to an actual inner class is to look up aClassInfo
in the index and examine the nesting type like so:index.getClassByName(name).nestingType() != TOP_LEVEL;
- Returns:
true
if local is an inner class style delimited name,false
otherwise
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toString
Returns the regular binary class name. -
toString
Returns the regular binary class name wheredelim
is used as a package separator.- Parameters:
delim
- the package separator; typically.
, but may be e.g./
to construct a bytecode descriptor- Returns:
- the binary class name with given character used as a package separator
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hashCode
public int hashCode()Returns a hash code which is based on the semantic representation of thisDotName
.Whether a
DotName
is componentized has no impact on the calculated hash code. In other words, a componentizedDotName
and a simpleDotName
that represent the same fully qualified name have the same hash code. -
equals
Compares aDotName
to anotherDotName
and returnstrue
if they represent the same underlying semantic name. In other words, whether a name is componentized or simple has no bearing on the comparison. -
compareTo
Compares aDotName
to anotherDotName
and returns whether thisDotName
is lesser than, greater than, or equal to the specified DotName. If thisDotName
is lesser, a negative value is returned. If greater, a positive value is returned. If equal, zero is returned.- Specified by:
compareTo
in interfaceComparable<DotName>
- Parameters:
other
- theDotName
to compare to- Returns:
- a negative number if this is less than the specified object, a positive if greater, and zero if equal
- See Also:
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