Class ImmutableIntArray
- java.lang.Object
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- com.google.common.primitives.ImmutableIntArray
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- All Implemented Interfaces:
java.io.Serializable
@GwtCompatible @Immutable public final class ImmutableIntArray extends java.lang.Object implements java.io.Serializable
An immutable array ofintvalues, with an API resemblingList.Advantages compared to
int[]:- All the many well-known advantages of immutability (read Effective Java, third edition, Item 17).
- Has the value-based (not identity-based)
equals(java.lang.Object),hashCode(), andtoString()behavior you expect. - Offers useful operations beyond just
getandlength, so you don't have to hunt through classes likeArraysandIntsfor them. - Supports a copy-free
subArray(int, int)view, so methods that accept this type don't need to add overloads that accept start and end indexes. - Can be streamed without "breaking the chain":
foo.getBarInts().stream().... - Access to all collection-based utilities via
asList()(though at the cost of allocating garbage).
Disadvantages compared to
int[]:- Memory footprint has a fixed overhead (about 24 bytes per instance).
- Some construction use cases force the data to be copied (though several construction APIs are offered that don't).
- Can't be passed directly to methods that expect
int[](though the most common utilities do have replacements here). - Dependency on
com.google.common/ Guava.
Advantages compared to
ImmutableList<Integer>:- Improved memory compactness and locality.
- Can be queried without allocating garbage.
- Access to
IntStreamfeatures (likeIntStream.sum()) usingstream()instead of the awkwardstream().mapToInt(v -> v).
Disadvantages compared to
ImmutableList<Integer>:- Can't be passed directly to methods that expect
Iterable,Collection, orList(though the most common utilities do have replacements here, and there is a lazyasList()view).
- Since:
- 22.0
- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classImmutableIntArray.BuilderA builder forImmutableIntArrayinstances; obtained usingbuilder(int).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description java.util.List<java.lang.Integer>asList()Returns an immutable view of this array's values as aList; note thatintvalues are boxed intoIntegerinstances on demand, which can be very expensive.static ImmutableIntArray.Builderbuilder()Returns a new, empty builder forImmutableIntArrayinstances, with a default initial capacity.static ImmutableIntArray.Builderbuilder(int initialCapacity)Returns a new, empty builder forImmutableIntArrayinstances, sized to hold up toinitialCapacityvalues without resizing.booleancontains(int target)Returnstrueiftargetis present at any index in this array.static ImmutableIntArraycopyOf(int[] values)Returns an immutable array containing the given values, in order.static ImmutableIntArraycopyOf(java.lang.Iterable<java.lang.Integer> values)Returns an immutable array containing the given values, in order.static ImmutableIntArraycopyOf(java.util.Collection<java.lang.Integer> values)Returns an immutable array containing the given values, in order.static ImmutableIntArraycopyOf(java.util.stream.IntStream stream)Returns an immutable array containing all the values fromstream, in order.booleanequals(java.lang.Object object)Returnstrueifobjectis anImmutableIntArraycontaining the same values as this one, in the same order.voidforEach(java.util.function.IntConsumer consumer)Invokesconsumerfor each value contained in this array, in order.intget(int index)Returns theintvalue present at the given index.inthashCode()Returns an unspecified hash code for the contents of this immutable array.intindexOf(int target)booleanisEmpty()Returnstrueif there are no values in this array (length()is zero).intlastIndexOf(int target)intlength()Returns the number of values in this array.static ImmutableIntArrayof()Returns the empty array.static ImmutableIntArrayof(int e0)Returns an immutable array containing a single value.static ImmutableIntArrayof(int e0, int e1)Returns an immutable array containing the given values, in order.static ImmutableIntArrayof(int first, int... rest)Returns an immutable array containing the given values, in order.static ImmutableIntArrayof(int e0, int e1, int e2)Returns an immutable array containing the given values, in order.static ImmutableIntArrayof(int e0, int e1, int e2, int e3)Returns an immutable array containing the given values, in order.static ImmutableIntArrayof(int e0, int e1, int e2, int e3, int e4)Returns an immutable array containing the given values, in order.static ImmutableIntArrayof(int e0, int e1, int e2, int e3, int e4, int e5)Returns an immutable array containing the given values, in order.java.util.stream.IntStreamstream()Returns a stream over the values in this array, in order.ImmutableIntArraysubArray(int startIndex, int endIndex)Returns a new immutable array containing the values in the specified range.int[]toArray()Returns a new, mutable copy of this array's values, as a primitiveint[].java.lang.StringtoString()Returns a string representation of this array in the same form asArrays.toString(int[]), for example"[1, 2, 3]".ImmutableIntArraytrimmed()Returns an immutable array containing the same values asthisarray.
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Method Detail
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of
public static ImmutableIntArray of()
Returns the empty array.
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of
public static ImmutableIntArray of(int e0)
Returns an immutable array containing a single value.
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of
public static ImmutableIntArray of(int e0, int e1)
Returns an immutable array containing the given values, in order.
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of
public static ImmutableIntArray of(int e0, int e1, int e2)
Returns an immutable array containing the given values, in order.
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of
public static ImmutableIntArray of(int e0, int e1, int e2, int e3)
Returns an immutable array containing the given values, in order.
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of
public static ImmutableIntArray of(int e0, int e1, int e2, int e3, int e4)
Returns an immutable array containing the given values, in order.
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of
public static ImmutableIntArray of(int e0, int e1, int e2, int e3, int e4, int e5)
Returns an immutable array containing the given values, in order.
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of
public static ImmutableIntArray of(int first, int... rest)
Returns an immutable array containing the given values, in order.The array
restmust not be longer thanInteger.MAX_VALUE - 1.
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copyOf
public static ImmutableIntArray copyOf(int[] values)
Returns an immutable array containing the given values, in order.
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copyOf
public static ImmutableIntArray copyOf(java.util.Collection<java.lang.Integer> values)
Returns an immutable array containing the given values, in order.
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copyOf
public static ImmutableIntArray copyOf(java.lang.Iterable<java.lang.Integer> values)
Returns an immutable array containing the given values, in order.Performance note: this method delegates to
copyOf(Collection)ifvaluesis aCollection. Otherwise it creates abuilder(int)and usesImmutableIntArray.Builder.addAll(Iterable), with all the performance implications associated with that.
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copyOf
public static ImmutableIntArray copyOf(java.util.stream.IntStream stream)
Returns an immutable array containing all the values fromstream, in order.
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builder
public static ImmutableIntArray.Builder builder(int initialCapacity)
Returns a new, empty builder forImmutableIntArrayinstances, sized to hold up toinitialCapacityvalues without resizing. The returned builder is not thread-safe.Performance note: When feasible,
initialCapacityshould be the exact number of values that will be added, if that knowledge is readily available. It is better to guess a value slightly too high than slightly too low. If the value is not exact, theImmutableIntArraythat is built will very likely occupy more memory than strictly necessary; to trim memory usage, build usingbuilder.build().trimmed().
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builder
public static ImmutableIntArray.Builder builder()
Returns a new, empty builder forImmutableIntArrayinstances, with a default initial capacity. The returned builder is not thread-safe.Performance note: The
ImmutableIntArraythat is built will very likely occupy more memory than necessary; to trim memory usage, build usingbuilder.build().trimmed().
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length
public int length()
Returns the number of values in this array.
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isEmpty
public boolean isEmpty()
Returnstrueif there are no values in this array (length()is zero).
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get
public int get(int index)
Returns theintvalue present at the given index.- Throws:
java.lang.IndexOutOfBoundsException- ifindexis negative, or greater than or equal tolength()
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indexOf
public int indexOf(int target)
Returns the smallest index for whichget(int)returnstarget, or-1if no such index exists. Equivalent toasList().indexOf(target).
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lastIndexOf
public int lastIndexOf(int target)
Returns the largest index for whichget(int)returnstarget, or-1if no such index exists. Equivalent toasList().lastIndexOf(target).
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contains
public boolean contains(int target)
Returnstrueiftargetis present at any index in this array. Equivalent toasList().contains(target).
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forEach
public void forEach(java.util.function.IntConsumer consumer)
Invokesconsumerfor each value contained in this array, in order.
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stream
public java.util.stream.IntStream stream()
Returns a stream over the values in this array, in order.
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toArray
public int[] toArray()
Returns a new, mutable copy of this array's values, as a primitiveint[].
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subArray
public ImmutableIntArray subArray(int startIndex, int endIndex)
Returns a new immutable array containing the values in the specified range.Performance note: The returned array has the same full memory footprint as this one does (no actual copying is performed). To reduce memory usage, use
subArray(start, end).trimmed().
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asList
public java.util.List<java.lang.Integer> asList()
Returns an immutable view of this array's values as aList; note thatintvalues are boxed intoIntegerinstances on demand, which can be very expensive. The returned list should be used once and discarded. For any usages beyond that, pass the returned list toImmutableList.copyOfand use that list instead.
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equals
public boolean equals(@CheckForNull java.lang.Object object)
Returnstrueifobjectis anImmutableIntArraycontaining the same values as this one, in the same order.- Overrides:
equalsin classjava.lang.Object
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hashCode
public int hashCode()
Returns an unspecified hash code for the contents of this immutable array.- Overrides:
hashCodein classjava.lang.Object
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toString
public java.lang.String toString()
Returns a string representation of this array in the same form asArrays.toString(int[]), for example"[1, 2, 3]".- Overrides:
toStringin classjava.lang.Object
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trimmed
public ImmutableIntArray trimmed()
Returns an immutable array containing the same values asthisarray. This is logically a no-op, and in some circumstancesthisitself is returned. However, if this instance is asubArray(int, int)view of a larger array, this method will copy only the appropriate range of values, resulting in an equivalent array with a smaller memory footprint.
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