org.grouplens.grapht.solver

Class DesireChain

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

org.grouplens.grapht.util.AbstractChain<Desire>

org.grouplens.grapht.solver.DesireChain

All Implemented Interfaces:

Serializable, Iterable<Desire>, Collection<Desire>, List<Desire>

public class DesireChain
extends AbstractChain<Desire>

A sequence of desires. When one desire is resolved, that resolution can be a desire that needs further resolution. These desires are accumulated in a desire chain. Desire chains are immutable; appending to one results in a new desire chain object pointing to the previous chain. They form a reverse singly linked list. The chain maintains O(1) access to both the initial and current desires.

When iterating a desire chain the initial desire is first and the most recent desire is last.

Since:

0.7.0

Author:

GroupLens Research

See Also:

Serialized Form

Field Summary

Fields inherited from class org.grouplens.grapht.util.AbstractChain

length, previous, tailValue

Fields inherited from class java.util.AbstractList

modCount

Method Summary

Methods

Modifier and Type	Method and Description
DesireChain	extend(Desire d) Extend this chain with a new desire.
Desire	getCurrentDesire()
Desire	getInitialDesire()
Object	getKey() Get this chain's key.
List<Desire>	getPreviousDesires() Return the list of desires up to, but not including, the current desire.
static com.google.common.base.Predicate<DesireChain>	hasInitialDesire(Desire d)
static DesireChain	singleton(Desire desire)

Methods inherited from class org.grouplens.grapht.util.AbstractChain

equals, get, getTailValue, hashCode, iterator, reverse, reverseIterator, size

Methods inherited from class java.util.AbstractList

add, add, addAll, clear, indexOf, lastIndexOf, listIterator, listIterator, remove, removeRange, set, subList

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Method Detail

singleton

public static DesireChain singleton(Desire desire)

hasInitialDesire

public static com.google.common.base.Predicate<DesireChain> hasInitialDesire(Desire d)

getCurrentDesire

@Nonnull
public Desire getCurrentDesire()

getInitialDesire

@Nonnull
public Desire getInitialDesire()

getPreviousDesires

@Nonnull
public List<Desire> getPreviousDesires()

Return the list of desires up to, but not including, the current desire.

Returns:

The previous desire chain.

getKey

public Object getKey()

Get this chain's key. Each chain has a key, a unique object that is created when the chain is created (via singleton(org.grouplens.grapht.reflect.Desire)), and preserved through extend(org.grouplens.grapht.reflect.Desire) operations. It can be used to remember state across invocations of a binding function as a desire chain is built up.

Returns:

The chain's key.

extend

@Nonnull
public DesireChain extend(@Nonnull
                         Desire d)

Extend this chain with a new desire. The chain is not modified; this method returns a new chain that includes the new desire as its current desire.

Parameters:

d - The new current desire.

Returns:

The new desire chain.