Permutation (Calcite Core 1.2.0-incubating API)

java.lang.Object
- org.apache.calcite.util.Permutation

All Implemented Interfaces:

Iterable<IntPair>, Mapping, Mappings.CoreMapping, Mappings.FunctionMapping, Mappings.SourceMapping, Mappings.TargetMapping
```
public class Permutation
extends Object
implements Mapping, Mappings.TargetMapping
```
Represents a mapping which reorders elements in an array.

Constructor Summary

Constructors
Constructor and Description

Permutation(int size)
Creates a permutation of a given size.

Permutation(int[] targets)
Creates a permutation from an array.

Constructors
Constructor and Description
`Permutation(int size)` Creates a permutation of a given size.
`Permutation(int[] targets)` Creates a permutation from an array.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clear()` Removes all elements in the mapping.
`Object`	`clone()`
`boolean`	`equals(Object obj)`
`MappingType`	`getMappingType()` Returns the mapping type.
`int`	`getSource(int target)` Returns the position which maps to `target`.
`int`	`getSourceCount()` Returns the number of sources.
`int`	`getSourceOpt(int target)`
`int`	`getTarget(int source)` Returns the position that `source` is mapped to.
`int`	`getTargetCount()` Returns the number of targets.
`int`	`getTargetOpt(int source)` Returns the target that a source maps to, or -1 if it is not mapped.
`int`	`hashCode()`
`void`	`identity()` Initializes this permutation to the identity permutation.
`void`	`insertSource(int x)` Inserts into the sources.
`void`	`insertTarget(int x)` Inserts into the targets.
`Permutation`	`inverse()` Returns the inverse permutation.
`boolean`	`isIdentity()` Returns whether this is the identity permutation.
`Iterator<IntPair>`	`iterator()` Returns an iterator over the elements in this mapping.
`Permutation`	`product(Permutation permutation)` Returns the product of this Permutation with a given Permutation.
`void`	`set(int source, int target)` Maps source position to target position.
`void`	`set(int source, int target, boolean allowResize)` Maps source position to target position, automatically resizing if source or target is out of bounds.
`void`	`setAll(Mapping mapping)`
`int`	`size()` Returns the number of elements in this permutation.
`String`	`toString()` Returns a string representation of this permutation.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Permutation
```
public Permutation(int size)
```
    Creates a permutation of a given size.
    It is initialized to the identity permutation, such as "[0, 1, 2, 3]".
    
    Parameters:
    size - Number of elements in the permutation
  - Permutation
```
public Permutation(int[] targets)
```
    Creates a permutation from an array.
    
    Parameters:
    targets - Array of targets
    
    Throws:
    
    IllegalArgumentException - if elements of array are not unique
    
    ArrayIndexOutOfBoundsException - if elements of array are not between 0 through targets.length - 1 inclusive
- Method Detail
  - clone
```
public Object clone()
```
    Overrides:
    
    clone in class Object
  - identity
```
public void identity()
```
    Initializes this permutation to the identity permutation.
  - size
```
public final int size()
```
    Returns the number of elements in this permutation.
    
    Specified by:
    
    size in interface Mapping
    
    Specified by:
    
    size in interface Mappings.CoreMapping
  - clear
```
public void clear()
```
    Description copied from interface: Mapping
    
    Removes all elements in the mapping.
    
    Specified by:
    
    clear in interface Mapping
  - toString
```
public String toString()
```
    Returns a string representation of this permutation.
    For example, the mapping
    Example mapping
    source target
    
    0 2
    
    1 0
    
    2 1
    
    3 3
    
    is represented by the string "[2, 0, 1, 3]".
    
    Overrides:
    
    toString in class Object
  - set
```
public void set(int source,
       int target)
```
    Maps source position to target position.
    To preserve the 1:1 nature of the permutation, the previous target of source becomes the new target of the previous source.
    For example, given the permutation
```
[3, 2, 0, 1]
```
    suppose we map position 2 to target 1. Position 2 currently has target 0, and the source of position 1 is position 3. We preserve the permutation property by mapping the previous source 3 to the previous target 0. The new permutation is
```
[3, 2, 1, 0].
```
    Another example. Again starting from
```
[3, 2, 0, 1]
```
    suppose we map position 2 to target 3. We map the previous source 0 to the previous target 0, which gives
```
[0, 2, 3, 1].
```
    Specified by:
    
    set in interface Mappings.TargetMapping
    
    Parameters:
    source - Source position
    target - Target position
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if source or target is negative or greater than or equal to the size of the permuation
  - set
```
public void set(int source,
       int target,
       boolean allowResize)
```
    Maps source position to target position, automatically resizing if source or target is out of bounds.
    To preserve the 1:1 nature of the permutation, the previous target of source becomes the new target of the previous source.
    For example, given the permutation
```
[3, 2, 0, 1]
```
    suppose we map position 2 to target 1. Position 2 currently has target 0, and the source of position 1 is position 3. We preserve the permutation property by mapping the previous source 3 to the previous target 0. The new permutation is
```
[3, 2, 1, 0].
```
    Another example. Again starting from
```
[3, 2, 0, 1]
```
    suppose we map position 2 to target 3. We map the previous source 0 to the previous target 0, which gives
```
[0, 2, 3, 1].
```
    Parameters:
    source - Source position
    target - Target position
    allowResize - Whether to resize the permutation if the source or target is greater than the current capacity
    
    Throws:
    
    ArrayIndexOutOfBoundsException - if source or target is negative, or greater than or equal to the size of the permutation, and allowResize is false
  - insertTarget
```
public void insertTarget(int x)
```
    Inserts into the targets.
    For example, consider the permutation
    
    Example permutation
    source 0 1 2 3 4
    
    target 3 0 4 2 1
    
    After applying insertTarget(2) every target 2 or higher is shifted up one.
    
    Mapping after applying insertTarget(2)
    source 0 1 2 3 4 5
    
    target 4 0 5 3 1 2
    
    Note that the array has been extended to accommodate the new target, and the previously unmapped source 5 is mapped to the unused target slot 2.
    
    Parameters:
    x - Ordinal of position to add to target
  - insertSource
```
public void insertSource(int x)
```
    Inserts into the sources.
    Behavior is analogous to insertTarget(int).
    
    Parameters:
    x - Ordinal of position to add to source
  - inverse
```
public Permutation inverse()
```
    Returns the inverse permutation.
    
    Specified by:
    
    inverse in interface Mappings.SourceMapping
    
    Specified by:
    
    inverse in interface Mappings.TargetMapping
  - isIdentity
```
public boolean isIdentity()
```
    Returns whether this is the identity permutation.
    
    Specified by:
    
    isIdentity in interface Mapping
    
    Specified by:
    
    isIdentity in interface Mappings.SourceMapping
  - getTarget
```
public int getTarget(int source)
```
    Returns the position that source is mapped to.
    
    Specified by:
    
    getTarget in interface Mappings.FunctionMapping
    
    Specified by:
    
    getTarget in interface Mappings.TargetMapping
    
    Parameters:
    source - source
    
    Returns:
    target
  - getSource
```
public int getSource(int target)
```
    Returns the position which maps to target.
    
    Specified by:
    
    getSource in interface Mappings.SourceMapping
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - iterator
```
public Iterator<IntPair> iterator()
```
    Description copied from interface: Mapping
    
    Returns an iterator over the elements in this mapping.
    This method is optional; implementations may throw UnsupportedOperationException.
    
    Specified by:
    
    iterator in interface Iterable<IntPair>
    
    Specified by:
    
    iterator in interface Mapping
  - getSourceCount
```
public int getSourceCount()
```
    Description copied from interface: Mapping
    
    Returns the number of sources. Valid sources will be in the range 0 .. sourceCount.
    
    Specified by:
    
    getSourceCount in interface Mapping
    
    Specified by:
    
    getSourceCount in interface Mappings.FunctionMapping
    
    Specified by:
    
    getSourceCount in interface Mappings.SourceMapping
    
    Specified by:
    
    getSourceCount in interface Mappings.TargetMapping
  - getTargetCount
```
public int getTargetCount()
```
    Description copied from interface: Mapping
    
    Returns the number of targets. Valid targets will be in the range 0 .. targetCount.
    
    Specified by:
    
    getTargetCount in interface Mapping
    
    Specified by:
    
    getTargetCount in interface Mappings.SourceMapping
    
    Specified by:
    
    getTargetCount in interface Mappings.TargetMapping
  - getMappingType
```
public MappingType getMappingType()
```
    Description copied from interface: Mappings.CoreMapping
    
    Returns the mapping type.
    
    Specified by:
    
    getMappingType in interface Mapping
    
    Specified by:
    
    getMappingType in interface Mappings.CoreMapping
    
    Specified by:
    
    getMappingType in interface Mappings.FunctionMapping
    
    Specified by:
    
    getMappingType in interface Mappings.SourceMapping
    
    Returns:
    Mapping type
  - getTargetOpt
```
public int getTargetOpt(int source)
```
    Description copied from interface: Mappings.FunctionMapping
    
    Returns the target that a source maps to, or -1 if it is not mapped.
    
    Specified by:
    
    getTargetOpt in interface Mappings.FunctionMapping
    
    Specified by:
    
    getTargetOpt in interface Mappings.SourceMapping
    
    Specified by:
    
    getTargetOpt in interface Mappings.TargetMapping
  - getSourceOpt
```
public int getSourceOpt(int target)
```
    Specified by:
    
    getSourceOpt in interface Mappings.SourceMapping
    
    Specified by:
    
    getSourceOpt in interface Mappings.TargetMapping
  - setAll
```
public void setAll(Mapping mapping)
```
  - product
```
public Permutation product(Permutation permutation)
```
    Returns the product of this Permutation with a given Permutation. Does not modify this Permutation or permutation.
    For example, perm.product(perm.inverse()) yields the identity.

Class Permutation

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Permutation

Permutation

Method Detail

clone

identity

size

clear

toString

set

set

insertTarget

insertSource

inverse

isIdentity

getTarget

getSource

hashCode

equals

iterator

getSourceCount

getTargetCount

getMappingType

getTargetOpt

getSourceOpt

setAll

product