edu.stanford.nlp.util

Class Pair<T1,T2>

java.lang.Object

edu.stanford.nlp.util.Pair<T1,T2>

All Implemented Interfaces:

PrettyLoggable, java.io.Serializable, java.lang.Comparable<Pair<T1,T2>>

Direct Known Subclasses:

Interval, UnorderedPair

public class Pair<T1,T2>
extends java.lang.Object
implements java.lang.Comparable<Pair<T1,T2>>, java.io.Serializable, PrettyLoggable

Pair is a Class for holding mutable pairs of objects.

Implementation note: On a 32-bit JVM uses ~ 8 (this) + 4 (first) + 4 (second) = 16 bytes. On a 64-bit JVM uses ~ 16 (this) + 8 (first) + 8 (second) = 32 bytes.

Many applications use a lot of Pairs so it's good to keep this number small.

Version:

2002/08/25

Author:

Dan Klein, Christopher Manning (added stuff from Kristina's, rounded out)

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Pair.ByFirstPairComparator<T1,T2> Compares a Pair to another Pair according to the first object of the pair only This function will work providing the first element of the Pair is comparable, otherwise will throw a ClassCastException.
static class	Pair.ByFirstReversePairComparator<T1,T2> Compares a Pair to another Pair according to the first object of the pair only in decreasing order This function will work providing the first element of the Pair is comparable, otherwise will throw a ClassCastException
static class	Pair.BySecondPairComparator<T1,T2> Compares a Pair to another Pair according to the second object of the pair only This function will work providing the first element of the Pair is comparable, otherwise will throw a ClassCastException
static class	Pair.BySecondReversePairComparator<T1,T2> Compares a Pair to another Pair according to the second object of the pair only in decreasing order This function will work providing the first element of the Pair is comparable, otherwise will throw a ClassCastException

Field Summary

Fields

Modifier and Type	Field and Description
T1	first Direct access is deprecated.
T2	second Direct access is deprecated.

Constructor Summary

Constructors

Constructor and Description
Pair()
Pair(T1 first, T2 second)

Method Summary

Modifier and Type	Method and Description
java.util.List<java.lang.Object>	asList()
int	compareTo(Pair<T1,T2> another) Compares this Pair to another object.
boolean	equals(java.lang.Object o)
T1	first()
int	hashCode()
static Pair<java.lang.String,java.lang.String>	internedStringPair(java.lang.String first, java.lang.String second) Returns an MutableInternedPair where the Strings have been interned.
static <X,Y> Pair<X,Y>	makePair(X x, Y y) Returns a Pair constructed from X and Y.
void	prettyLog(Redwood.RedwoodChannels channels, java.lang.String description) Pretty logs the current object to specific Redwood channels.
void	save(java.io.DataOutputStream out) Write a string representation of a Pair to a DataStream.
T2	second()
void	setFirst(T1 o)
void	setSecond(T2 o)
static Pair<java.lang.String,java.lang.String>	stringIntern(Pair<java.lang.String,java.lang.String> p) If first and second are Strings, then this returns an MutableInternedPair where the Strings have been interned, and if this Pair is serialized and then deserialized, first and second are interned upon deserialization.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

first

public T1 first

Direct access is deprecated. Use first().

second

public T2 second

Direct access is deprecated. Use second().

Constructor Detail

Pair

public Pair()

Pair

public Pair(T1 first,
            T2 second)

Method Detail

first

public T1 first()

second

public T2 second()

setFirst

public void setFirst(T1 o)

setSecond

public void setSecond(T2 o)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

asList

public java.util.List<java.lang.Object> asList()

makePair

public static <X,Y> Pair<X,Y> makePair(X x,
                                       Y y)

Returns a Pair constructed from X and Y. Convenience method; the compiler will disambiguate the classes used for you so that you don't have to write out potentially long class names.

save

public void save(java.io.DataOutputStream out)

Write a string representation of a Pair to a DataStream. The toString() method is called on each of the pair of objects and a String representation is written. This might not allow one to recover the pair of objects unless they are of type String.

compareTo

public int compareTo(Pair<T1,T2> another)

Compares this Pair to another object. If the object is a Pair, this function will work providing the elements of the Pair are themselves comparable. It will then return a value based on the pair of objects, where p > q iff p.first() > q.first() || (p.first().equals(q.first()) && p.second() > q.second()). If the other object is not a Pair, it throws a ClassCastException.

Specified by:

compareTo in interface java.lang.Comparable<Pair<T1,T2>>

Parameters:

another - the Object to be compared.

Returns:

the value 0 if the argument is a Pair equal to this Pair; a value less than 0 if the argument is a Pair greater than this Pair; and a value greater than 0 if the argument is a Pair less than this Pair.

Throws:

java.lang.ClassCastException - if the argument is not a Pair.

See Also:

Comparable

stringIntern

public static Pair<java.lang.String,java.lang.String> stringIntern(Pair<java.lang.String,java.lang.String> p)

If first and second are Strings, then this returns an MutableInternedPair where the Strings have been interned, and if this Pair is serialized and then deserialized, first and second are interned upon deserialization.

Parameters:

p - A pair of Strings

Returns:

MutableInternedPair, with same first and second as this.

internedStringPair

public static Pair<java.lang.String,java.lang.String> internedStringPair(java.lang.String first,
                                                                         java.lang.String second)

Returns an MutableInternedPair where the Strings have been interned. This is a factory method for creating an MutableInternedPair. It requires the arguments to be Strings. If this Pair is serialized and then deserialized, first and second are interned upon deserialization.

Note: I put this in thinking that its use might be faster than calling x = new Pair(a, b).stringIntern() but it's not really clear whether this is true.

Parameters:

first - The first object

second - The second object

Returns:

An MutableInternedPair, with given first and second

prettyLog

public void prettyLog(Redwood.RedwoodChannels channels,
                      java.lang.String description)

Pretty logs the current object to specific Redwood channels.

Specified by:

prettyLog in interface PrettyLoggable

Parameters:

channels - the channels which should be logged to -- all logging calls should use logging methods on the channels (e.g. channels.log(), etc.)

description - The description of the object. It will potentially identify the object's functional role or (failing that) its class. This is typically used as a track name surrounding the contents of this object.