Top Description Fields Constructors Methods
org.apache.derby.iapi.store.raw

public final Class PageKey

extends Object
Class Inheritance
Imports
org.apache.derby.iapi.store.raw.ContainerKey, org.apache.derby.shared.common.sanity.SanityManager, org.apache.derby.iapi.services.io.CompressedNumber, java.io.ObjectOutput, .ObjectInput, .IOException

A key that identifies a BasePage. Used as the key for the caching mechanism.
MT - Immutable :

Field Summary

Modifier and TypeField and Description
private final ContainerKey
private final long

Constructor Summary

AccessConstructor and Description
public
PageKey(ContainerKey key, long pageNumber)

Method Summary

Modifier and TypeMethod and Description
public boolean
equals(Object
the reference object with which to compare.
other
)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

public ContainerKey
public long
public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public static PageKey
public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

public void
Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

containerback to summary
private final ContainerKey container
pageNumberback to summary
private final long pageNumber

Constructor Detail

PageKeyback to summary
public PageKey(ContainerKey key, long pageNumber)

Method Detail

equalsback to summary
public boolean equals(Object other)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
other:Object

the reference object with which to compare.

Returns:boolean

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

getContainerIdback to summary
public ContainerKey getContainerId()
getPageNumberback to summary
public long getPageNumber()
hashCodeback 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

readback to summary
public static PageKey read(ObjectInput in) throws IOException
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

writeExternalback to summary
public void writeExternal(ObjectOutput out) throws IOException