gzz.slices
Class SliceVersion.Diff

java.lang.Object
  |
  +--gzz.slices.SliceVersion.Diff

All Implemented Interfaces:

java.io.Serializable, Version.Diff

Enclosing class:

SliceVersion

public static class SliceVersion.Diff

extends java.lang.Object

implements java.io.Serializable, Version.Diff

A diff between two SliceVersions.

See Also:

Serialized Form

Field Summary

java.util.Set	connects The set of Conn objects created by this diff.
java.util.Map	contents The cell contents set by this diff.
java.util.Set	disconnects The set of Conn objects removed by this diff.
java.util.Map	discontents The cell contents unset by this diff.

Constructor Summary

SliceVersion.Diff(java.util.Set connects, java.util.Set disconnects, java.util.Map contents, java.util.Map discontents)
Create a new Diff by giving the fields of the object.

SliceVersion.Diff(SliceVersion old, SliceVersion nu)
Create a new Diff by comparing an 'old' against a 'new' SliceVersion.

Method Summary

Version	applyTo(Version _old) Apply the diff to a SliceVersion and return the result.
Version.Diff	inverse() Return the inverse of this diff.
boolean	isEmpty() Whether this is the empty diff.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

connects

public final java.util.Set connects

The set of Conn objects created by this diff.

disconnects

public final java.util.Set disconnects

The set of Conn objects removed by this diff.

contents

public final java.util.Map contents

The cell contents set by this diff. The map has the same form as in SliceVersion.

discontents

public final java.util.Map discontents

The cell contents unset by this diff. The map has the same form as the connects map. This is the inverse of the contents map: if cell C had content A before and content B after the diff, C will be mapped to B in contents but to A in discontents.

Constructor Detail

SliceVersion.Diff

public SliceVersion.Diff(SliceVersion old,
                         SliceVersion nu)

Create a new Diff by comparing an 'old' against a 'new' SliceVersion. For all SliceVersions o and n, it must hold that: Diff(o, n).applyTo(o) == n and Diff(o, n).inverse().applyTo(n) == o.

Note: We do not do consistency checking because we believe the SliceVersions to be consistent, and our simple diffing algorithm to be sound.

SliceVersion.Diff

public SliceVersion.Diff(java.util.Set connects,
                         java.util.Set disconnects,
                         java.util.Map contents,
                         java.util.Map discontents)

Create a new Diff by giving the fields of the object. This is private because we do not check.

Method Detail

inverse

public Version.Diff inverse()

Return the inverse of this diff.

Specified by:

inverse in interface Version.Diff

applyTo

public Version applyTo(Version _old)

Apply the diff to a SliceVersion and return the result.

Specified by:

applyTo in interface Version.Diff

isEmpty

public boolean isEmpty()

Description copied from interface: Version.Diff

Whether this is the empty diff. It must hold that v.equals(diff.applyTo(v)) for all Versions v and Version.Diffs diff of the matching kind, iff diff.isEmpty().

We need this method because we never want to save empty diffs...

Specified by:

isEmpty in interface Version.Diff

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object