Modifier and Type	Class and Description
public static class	Interners.InternerBuilder Builder for `Interner` instances.
private static class	Interners.InternerFunction<E>
pack-priv static class	Interners.InternerImpl<E>

Access	Constructor and Description
private	Interners()

Modifier and Type	Method and Description
public static <E> Function<E, E>	asFunction(Interner<E> interner) Returns a function that delegates to the `Interner#intern` method of the given interner.
public static Interners.InternerBuilder	newBuilder() Returns a fresh `InternerBuilder` instance.
public static <E> Interner<E>	newStrongInterner() Returns a new thread-safe interner which retains a strong reference to each instance it has interned, thus preventing these instances from being garbage-collected.
public static <E> Interner<E>	newWeakInterner() Returns a new thread-safe interner which retains a weak reference to each instance it has interned, and so does not prevent these instances from being garbage-collected.

Interners	back to summary
private Interners()

Method Detail

asFunction back to summary

asFunction	back to summary
public static <E> Function<E, E> asFunction(Interner<E> interner) Returns a function that delegates to the `Interner#intern` method of the given interner. Since 8.0

public static <E> Function<E, E> asFunction(Interner<E> interner)

Returns a function that delegates to the Interner#intern method of the given interner.

Since: 8.0

newBuilder	back to summary
public static Interners.InternerBuilder newBuilder() Returns a fresh `InternerBuilder` instance.

newStrongInterner	back to summary
public static <E> Interner<E> newStrongInterner() Returns a new thread-safe interner which retains a strong reference to each instance it has interned, thus preventing these instances from being garbage-collected. If this retention is acceptable, this implementation may perform better than `newWeakInterner`.

newWeakInterner back to summary

newWeakInterner	back to summary
public static <E> Interner<E> newWeakInterner() Returns a new thread-safe interner which retains a weak reference to each instance it has interned, and so does not prevent these instances from being garbage-collected. This most likely does not perform as well as `newStrongInterner`, but is the best alternative when the memory usage of that implementation is unacceptable. Annotations @GwtIncompatible:WeakReference

public static <E> Interner<E> newWeakInterner()

Returns a new thread-safe interner which retains a weak reference to each instance it has interned, and so does not prevent these instances from being garbage-collected. This most likely does not perform as well as newStrongInterner, but is the best alternative when the memory usage of that implementation is unacceptable.

Annotations

@GwtIncompatible:WeakReference

com.google.common.collect back to summary

public Class Interners.InternerBuilder

Class Inheritance

extends Object

java.lang.Object
com.google.common.collect.Interners.InternerBuilder

Builder for Interner instances.

Since: 21.0

Field Summary

Modifier and Type	Field and Description
private final MapMaker	mapMaker
private boolean	strong

Constructor Summary

Access	Constructor and Description
private	InternerBuilder()

Method Summary

Modifier and Type	Method and Description
public <E> Interner<E>	build()
public Interners.InternerBuilder	concurrencyLevel(int concurrencyLevel) Sets the concurrency level that will be used by the to-be-built `Interner`.
public Interners.InternerBuilder	strong() Instructs the `InternerBuilder` to build a strong interner.
public Interners.InternerBuilder	weak() Instructs the `InternerBuilder` to build a weak interner.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

mapMaker	back to summary
private final MapMaker mapMaker

strong	back to summary
private boolean strong

Constructor Detail

InternerBuilder	back to summary
private InternerBuilder()

Method Detail

build	back to summary
public <E> Interner<E> build()

concurrencyLevel back to summary

concurrencyLevel	back to summary
public Interners.InternerBuilder concurrencyLevel(int concurrencyLevel) Sets the concurrency level that will be used by the to-be-built `Interner`. See Also `MapMaker#concurrencyLevel(int)`

public Interners.InternerBuilder concurrencyLevel(int concurrencyLevel)

Sets the concurrency level that will be used by the to-be-built Interner.

See Also: MapMaker#concurrencyLevel(int)

strong back to summary

strong	back to summary
public Interners.InternerBuilder strong() Instructs the `InternerBuilder` to build a strong interner. See Also `Interners#newStrongInterner()`

public Interners.InternerBuilder strong()

Instructs the InternerBuilder to build a strong interner.

See Also: Interners#newStrongInterner()

weak back to summary

weak	back to summary
public Interners.InternerBuilder weak() Instructs the `InternerBuilder` to build a weak interner. Annotations @GwtIncompatible:WeakReference See Also `Interners#newWeakInterner()`

public Interners.InternerBuilder weak()

Instructs the InternerBuilder to build a weak interner.

Annotations

@GwtIncompatible:WeakReference

See Also

Interners#newWeakInterner()

com.google.common.collect back to summary

private Class Interners.InternerFunction<E>

Class Inheritance

extends Object
implements Function<E, E>

java.lang.Object
com.google.common.collect.Interners.InternerFunction

All Implemented Interfaces

com.google.common.base.Function, java.util.function.Function

Field Summary

Modifier and Type	Field and Description
private final Interner<E>	interner

Constructor Summary

Access	Constructor and Description
public	InternerFunction(Interner<E> interner)

Method Summary

Modifier and Type	Method and Description
public E	apply(E the function argument input) Implements com.google.common.base.Function.apply. Applies this function to the given argument.
public boolean	equals(Object the reference object with which to compare. other) Overrides java.lang.Object.equals. Implements com.google.common.base.Function.equals. May return `true` if `object` is a `Function` that behaves identically to this function.
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for this object.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll toString wait wait wait

Field Detail

interner	back to summary
private final Interner<E> interner

Constructor Detail

InternerFunction	back to summary
public InternerFunction(Interner<E> interner)

Method Detail

apply	back to summary
public E apply(E input) Implements com.google.common.base.Function.apply. Doc from java.util.function.Function.apply. Applies this function to the given argument. Parameters input:E the function argument Returns:E the function result Annotations @Override

apply

back to summary

public E apply(E input)

Implements com.google.common.base.Function.apply.

Doc from java.util.function.Function.apply.

Applies this function to the given argument.

Parameters

input:E: the function argument

Returns:E

the function result

Annotations

@Override

equals back to summary

equals	back to summary
public boolean equals(Object other) Overrides java.lang.Object.equals. Implements com.google.common.base.Function.equals. Doc from com.google.common.base.Function.equals. May return `true` if `object` is a `Function` that behaves identically to this function. Warning: do not depend on the behavior of this method. Historically, `Function` instances in this library have implemented this method to recognize certain cases where distinct `Function` instances would in fact behave identically. However, as code migrates to `java.util.function`, that behavior will disappear. It is best not to depend on it. Parameters other:Object Doc from java.lang.Object.equals. the reference object with which to compare. Returns:boolean Doc from java.lang.Object.equals. `true` if this object is the same as the obj argument; `false` otherwise. Annotations @Override

public boolean equals(Object other)

Overrides java.lang.Object.equals.

Implements com.google.common.base.Function.equals.

Doc from com.google.common.base.Function.equals.

May return true if object is a Function that behaves identically to this function.

Warning: do not depend on the behavior of this method.

Historically, Function instances in this library have implemented this method to recognize certain cases where distinct Function instances would in fact behave identically. However, as code migrates to java.util.function, that behavior will disappear. It is best not to depend on it.

Parameters

other:Object

Doc from java.lang.Object.equals.

the reference object with which to compare.

Returns:boolean

Doc from java.lang.Object.equals.

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Doc from java.lang.Object.hashCode. Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by `java.util.HashMap`. The general contract of `hashCode` is: Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. Returns:int a hash code value for this object Annotations @Override

public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Returns:int

a hash code value for this object

Annotations

@Override

com.google.common.collect back to summary

pack-priv final Class Interners.InternerImpl<E>

Class Inheritance

extends Object
implements Interner<E>

java.lang.Object
com.google.common.collect.Interners.InternerImpl

All Implemented Interfaces

com.google.common.collect.Interner

Annotations

@VisibleForTesting

Field Summary

Modifier and Type	Field and Description
pack-priv final MapMakerInternalMap<E, MapMaker.Dummy, ?, ?>	map

Constructor Summary

Access	Constructor and Description
private	InternerImpl(MapMaker mapMaker)

Method Summary

Modifier and Type	Method and Description
public E	intern(E sample) Implements com.google.common.collect.Interner.intern. Chooses and returns the representative instance for any of a collection of instances that are equal to each other.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

map	back to summary
pack-priv final MapMakerInternalMap<E, MapMaker.Dummy, ?, ?> map Annotations @VisibleForTesting

Constructor Detail

InternerImpl	back to summary
private InternerImpl(MapMaker mapMaker)

Method Detail

intern back to summary

intern	back to summary
public E intern(E sample) Implements com.google.common.collect.Interner.intern. Doc from com.google.common.collect.Interner.intern. Chooses and returns the representative instance for any of a collection of instances that are equal to each other. If two equal inputs are given to this method, both calls will return the same instance. That is, `intern(a).equals(a)` always holds, and `intern(a) == intern(b)` if and only if `a.equals(b)`. Note that `intern(a)` is permitted to return one instance now and a different instance later if the original interned instance was garbage-collected. Warning do not use with mutable objects. Annotations @Override

public E intern(E sample)

Implements com.google.common.collect.Interner.intern.

Doc from com.google.common.collect.Interner.intern.

Chooses and returns the representative instance for any of a collection of instances that are equal to each other. If two equal inputs are given to this method, both calls will return the same instance. That is, intern(a).equals(a) always holds, and intern(a) == intern(b) if and only if a.equals(b). Note that intern(a) is permitted to return one instance now and a different instance later if the original interned instance was garbage-collected.

Warning

do not use with mutable objects.

Annotations

@Override

public final Class Interners

Nested and Inner Type Summary

Constructor Summary

Method Summary

Constructor Detail

Method Detail

public Class Interners.InternerBuilder

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class Interners.InternerFunction<E>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

pack-priv final Class Interners.InternerImpl<E>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail