Comparable

public interface Comparable

Known Indirect Subclasses Allocation.MipmapControl, AlphabeticIndex.Bucket.LabelType, AsyncTask.Status, Authenticator.RequestorType, BigDecimal, BigInteger, Bitmap.CompressFormat, Bitmap.Config, BlurMaskFilter.Blur, Boolean, BuddhistCalendar, Byte, and 152 others. Allocation.MipmapControl Controls mipmap behavior when using the bitmap creation and update functions.  AlphabeticIndex.Bucket.LabelType Type of the label   AsyncTask.Status Indicates the current status of the task.  Authenticator.RequestorType The type of the entity requesting authentication.  BigDecimal The BigDecimal class implements immutable arbitrary-precision decimal numbers.  BigInteger An immutable arbitrary-precision signed integer.  Bitmap.CompressFormat Specifies the known formats a bitmap can be compressed into   Bitmap.Config Possible bitmap configurations.  BlurMaskFilter.Blur   Boolean The Boolean class wraps a value of the primitive type boolean in an object.  BuddhistCalendar BuddhistCalendar is a subclass of GregorianCalendar that numbers years since the birth of the Buddha.  Byte The Byte class wraps a value of primitive type byte in an object.  ByteBuffer A byte buffer.  CRLReason The CRLReason enumeration specifies the reason that a certificate is revoked, as defined in RFC 3280: Internet X.509 Public Key Infrastructure Certificate and CRL Profile.  Calendar [icu enhancement] ICU's replacement for Calendar. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.  Canvas.EdgeType   Canvas.VertexMode   CertPathValidatorException.BasicReason The BasicReason enumerates the potential reasons that a certification path of any type may be invalid.  CharBuffer A char buffer.  Character The Character class wraps a value of the primitive type char in an object.  Character.UnicodeScript A family of character subsets representing the character scripts defined in the Unicode Standard Annex #24: Script Names.  Charset A named mapping between sequences of sixteen-bit Unicode code units and sequences of bytes.  CheckBoxPreference A Preference that provides checkbox widget functionality.  ChineseCalendar ChineseCalendar is a concrete subclass of Calendar that implements a traditional Chinese calendar.  ClientInfoStatus Enumeration for status of the reason that a property could not be set via a call to Connection.setClientInfo  CollationKey A CollationKey represents a String under the rules of a specific Collator object.  Collector.Characteristics Characteristics indicating properties of a Collector, which can be used to optimize reduction implementations.  CompactDecimalFormat.CompactStyle Style parameter for CompactDecimalFormat.  ComponentName Identifier for a specific application component (Activity, Service, BroadcastReceiver, or ContentProvider) that is available.  Configuration This class describes all device configuration information that can impact the resources the application retrieves.  ConsoleMessage.MessageLevel   CopticCalendar Implement the Coptic calendar system.  CryptoPrimitive An enumeration of cryptographic primitives.  Currency.CurrencyUsage Currency Usage used for Decimal Format   CursorJoiner.Result The result of a call to next().  Date The class Date represents a specific instant in time, with millisecond precision.  DateFormat.BooleanAttribute boolean attributes   Delayed A mix-in style interface for marking objects that should be acted upon after a given delay.  DialogPreference A base class for Preference objects that are dialog-based.  DisplayContext Display context settings.  DisplayContext.Type Type values for DisplayContext   Double The Double class wraps a value of the primitive type double in an object.  DoubleBuffer A double buffer.  DropDownPreference A version of ListPreference that presents the options in a drop down menu rather than a dialog.  EditTextPreference A Preference that allows for string input.  Element.DataKind The special interpretation of the data if required.  Element.DataType DataType represents the basic type information for a basic element.  ElementType A program element type.  Enum<E extends Enum<E>> This is the common base class of all Java language enumeration types.  File An abstract representation of file and directory pathnames.  Float The Float class wraps a value of primitive type float in an object.  FloatBuffer A float buffer.  Formatter.BigDecimalLayoutForm   GradientDrawable.Orientation Controls how the gradient is oriented relative to the drawable's bounds   GregorianCalendar [icu enhancement] ICU's replacement for GregorianCalendar. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.  HebrewCalendar HebrewCalendar is a subclass of Calendar that that implements the traditional Hebrew calendar.  IDNA.Error IDNA error bit set values.  ImageView.ScaleType Options for scaling the bounds of an image to the bounds of this view.  IndianCalendar IndianCalendar is a subclass of GregorianCalendar that numbers years since the birth of the Buddha.  IntBuffer An int buffer.  Integer The Integer class wraps a value of the primitive type int in an object.  Interpolator.Result   IslamicCalendar IslamicCalendar is a subclass of Calendar that that implements the Islamic civil and religious calendars.  IslamicCalendar.CalculationType enumeration of available calendar calculation types   JapaneseCalendar JapaneseCalendar is a subclass of GregorianCalendar that numbers years and eras based on the reigns of the Japanese emperors.  JsonToken A structure, name or value type in a JSON-encoded string.  KeyRep.Type Key type.  Layout.Alignment   ListPreference A Preference that displays a list of entries as a dialog.  LocalSocketAddress.Namespace The namespace that this address exists in.  Locale.Category Enum for locale categories.  LocaleDisplayNames.DialectHandling Enum used in getInstance(ULocale, DialectHandling).  Long The Long class wraps a value of the primitive type long in an object.  LongBuffer A long buffer.  MappedByteBuffer A direct byte buffer whose content is a memory-mapped region of a file.  Matrix.ScaleToFit Controlls how the src rect should align into the dst rect for setRectToRect().  MeasureFormat.FormatWidth Formatting width enum.  MessagePattern.ApostropheMode Mode for when an apostrophe starts quoted literal text for MessageFormat output.  MessagePattern.ArgType Argument type constants.  MessagePattern.Part.Type Part type constants.  MultiSelectListPreference A Preference that displays a list of entries as a dialog.  NetworkInfo.DetailedState The fine-grained state of a network connection.  NetworkInfo.State Coarse-grained network state.  Normalizer.Form This enum provides constants of the four Unicode normalization forms that are described in Unicode Standard Annex #15 — Unicode Normalization Forms and two methods to access them.  Normalizer2.Mode Constants for normalization modes.  NumericShaper.Range A NumericShaper.Range represents a Unicode range of a script having its own decimal digits.  ObjectStreamField A description of a Serializable field from a Serializable class.  PKIXReason The PKIXReason enumerates the potential PKIX-specific reasons that an X.509 certification path may be invalid according to the PKIX (RFC 3280) standard.  PKIXRevocationChecker.Option Various revocation options that can be specified for the revocation checking mechanism.  Paint.Align Align specifies how drawText aligns its text relative to the [x,y] coordinates.  Paint.Cap The Cap specifies the treatment for the beginning and ending of stroked lines and paths.  Paint.Join The Join specifies the treatment where lines and curve segments join on a stroked path.  Paint.Style The Style specifies if the primitive being drawn is filled, stroked, or both (in the same color).  Path.Direction Specifies how closed shapes (e.g.  Path.FillType Enum for the ways a path may be filled.  Path.Op The logical operations that can be performed when combining two paths.  PathDashPathEffect.Style   PluralRules.PluralType Type of plurals and PluralRules.  PorterDuff.Mode   Preference Represents the basic Preference UI building block displayed by a PreferenceActivity in the form of a ListView.  PreferenceCategory Used to group Preference objects and provide a disabled title above the group.  PreferenceGroup A container for multiple Preference objects.  PreferenceScreen Represents a top-level Preference that is the root of a Preference hierarchy.  Proxy.Type Represents the proxy type.  Rational An immutable data type representation a rational number.  Region.Op   RelativeDateTimeFormatter.AbsoluteUnit Represents an absolute unit.  RelativeDateTimeFormatter.Direction Represents a direction for an absolute unit e.g "Next Tuesday" or "Last Tuesday"   RelativeDateTimeFormatter.RelativeUnit Represents the unit for formatting a relative date.  RelativeDateTimeFormatter.Style The formatting style   RenderScript.ContextType ContextType specifies the specific type of context to be created.  RenderScript.Priority RenderScript worker thread priority enumeration.  RetentionPolicy Annotation retention policy.  RingtonePreference A Preference that allows the user to choose a ringtone from those on the device.  RoundingMode Specifies the rounding behavior for operations whose results cannot be represented exactly.  RowIdLifetime Enumeration for RowId life-time values.  RunnableScheduledFuture<V> A ScheduledFuture that is Runnable.  SSLEngineResult.HandshakeStatus An SSLEngineResult enum describing the current handshaking state of this SSLEngine.  SSLEngineResult.Status An SSLEngineResult enum describing the overall result of the SSLEngine operation.  Sampler.Value   ScheduledFuture<V> A delayed result-bearing action that can be cancelled.  SearchIterator.ElementComparisonType Option to control how collation elements are compared.  Shader.TileMode   Short The Short class wraps a value of primitive type short in an object.  ShortBuffer A short buffer.  SmsMessage.MessageClass This enum was deprecated in API level 4. Use android.telephony.SmsMessage.   StandardProtocolFamily Defines the standard families of communication protocols.  String The String class represents character strings.  SupplicantState From defs.h in wpa_supplicant.  SwitchPreference A Preference that provides a two-state toggleable option.  SwitchPreferenceCompat A Preference that provides a two-state toggleable option.  TaiwanCalendar TaiwanCalendar is a subclass of GregorianCalendar that numbers years since 1912.  TextKeyListener.Capitalize   TextUtils.TruncateAt   TextView.BufferType   Thread.State A thread state.  Time A thin wrapper around the java.util.Date class that allows the JDBC API to identify this as an SQL TIME value.  TimeUnit A TimeUnit represents time durations at a given unit of granularity and provides utility methods to convert across units, and to perform timing and delay operations in these units.  TimeZone.SystemTimeZoneType [icu] System time zone type constants used by filtering zones in getAvailableIDs(SystemTimeZoneType, String, Integer)   TimeZoneFormat.GMTOffsetPatternType Offset pattern type enum.  TimeZoneFormat.ParseOption Parse option enum, used for specifying optional parse behavior.  TimeZoneFormat.Style Time zone display format style enum used by format/parse APIs in TimeZoneFormat.  TimeZoneFormat.TimeType Time type enum used for receiving time type (standard time, daylight time or unknown) in TimeZoneFormat APIs.  TimeZoneNames.NameType Time zone display name types   Timestamp A thin wrapper around java.util.Date that allows the JDBC API to identify this as an SQL TIMESTAMP value.  TwoStatePreference Common base class for preferences that have two selectable states, persist a boolean value in SharedPreferences, and may have dependent preferences that are enabled/disabled based on the current state.  Type.CubemapFace   ULocale [icu enhancement] ICU's replacement for Locale. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.  ULocale.Category Enum for locale categories.  URI Represents a Uniform Resource Identifier (URI) reference.  UScript.ScriptUsage Script usage constants.  UUID A class that represents an immutable universally unique identifier (UUID).  UnicodeSet A mutable set of Unicode characters and multicharacter strings.  UnicodeSet.ComparisonStyle Comparison style enums used by compareTo(UnicodeSet, ComparisonStyle).  UnicodeSet.SpanCondition Argument values for whether span() and similar functions continue while the current character is contained vs.  UnicodeSetSpanner.CountMethod Options for replaceFrom and countIn to control how to treat each matched span.  UnicodeSetSpanner.TrimOption Options for the trim() method   Uri Immutable URI reference.  VersionInfo Class to store version numbers of the form major.minor.milli.micro.  ViewDebug.HierarchyTraceType This enum was deprecated in API level 16. This enum is now unused   ViewDebug.RecyclerTraceType This enum was deprecated in API level 16. This enum is now unused   WebSettings.LayoutAlgorithm Enum for controlling the layout of html.  WebSettings.PluginState The plugin state effects how plugins are treated on a page.  WebSettings.RenderPriority   WebSettings.TextSize This enum was deprecated in API level 14. Use setTextZoom(int) and getTextZoom() instead.   WebSettings.ZoomDensity Enum for specifying the WebView's desired density.  Xml.Encoding Supported character encodings.

This interface imposes a total ordering on the objects of each class that implements it. This ordering is referred to as the class's natural ordering, and the class's compareTo method is referred to as its natural comparison method.

Lists (and arrays) of objects that implement this interface can be sorted automatically by Collections.sort (and Arrays.sort). Objects that implement this interface can be used as keys in a sorted map or as elements in a sorted set, without the need to specify a comparator.

The natural ordering for a class C is said to be consistent with equals if and only if e1.compareTo(e2) == 0 has the same boolean value as e1.equals(e2) for every e1 and e2 of class C. Note that null is not an instance of any class, and e.compareTo(null) should throw a NullPointerException even though e.equals(null) returns false.

It is strongly recommended (though not required) that natural orderings be consistent with equals. This is so because sorted sets (and sorted maps) without explicit comparators behave "strangely" when they are used with elements (or keys) whose natural ordering is inconsistent with equals. In particular, such a sorted set (or sorted map) violates the general contract for set (or map), which is defined in terms of the equals method.

For example, if one adds two keys a and b such that (!a.equals(b) && a.compareTo(b) == 0) to a sorted set that does not use an explicit comparator, the second add operation returns false (and the size of the sorted set does not increase) because a and b are equivalent from the sorted set's perspective.

Virtually all Java core classes that implement Comparable have natural orderings that are consistent with equals. One exception is java.math.BigDecimal, whose natural ordering equates BigDecimal objects with equal values and different precisions (such as 4.0 and 4.00).

For the mathematically inclined, the relation that defines the natural ordering on a given class C is:

       {(x, y) such that x.compareTo(y) <= 0}.
 

       {(x, y) such that x.compareTo(y) == 0}.
 

     {(x, y) such that x.equals(y)}. 

This interface is a member of the Java Collections Framework.

Summary

Public methods

int compareTo (T o)