org.eclipse.equinox.internal.p2.metadata

Class Requirement

java.lang.Object

org.eclipse.equinox.internal.p2.metadata.Requirement

All Implemented Interfaces:

IMemberProvider, IRequirement

Direct Known Subclasses:

RequiredCapability, RequiredPropertiesMatch

public class Requirement
extends java.lang.Object
implements IRequirement, IMemberProvider

A requirement represents some external constraint on an IInstallableUnit. Each requirement represents something an IInstallableUnit needs that it expects to be provided by another IInstallableUnit. Requirements are entirely generic, and are intended to be capable of representing anything that an IInstallableUnit may need either at install time, or at runtime.

Instances of this class are handle objects and do not necessarily reflect entities that exist in any particular profile or repository. These handle objects can be created using MetadataFactory.

Since:

2.0

See Also:

IProvidedCapability, MetadataFactory.createRequirement(String, String, VersionRange, String, boolean, boolean, boolean)

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	description
protected IMatchExpression<IInstallableUnit>	filter
protected boolean	greedy
protected IMatchExpression<IInstallableUnit>	matchExpression
protected int	max
static java.lang.String	MEMBER_FILTER
static java.lang.String	MEMBER_GREEDY
static java.lang.String	MEMBER_MATCH
static java.lang.String	MEMBER_MAX
static java.lang.String	MEMBER_MIN
protected int	min

Constructor Summary

Constructors

Constructor and Description
Requirement(IMatchExpression<IInstallableUnit> requirement, IMatchExpression<IInstallableUnit> filter, int min, int max, boolean greedy, java.lang.String description)

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
java.lang.String	getDescription() Returns a textual description of this requirement.
IMatchExpression<IInstallableUnit>	getFilter()
IMatchExpression<IInstallableUnit>	getMatches() Returns a boolean match expression that will return true for any IInstallableUnit that matches the requirement.
int	getMax() Returns the maximum cardinality of the requirement.
java.lang.Object	getMember(java.lang.String memberName) Returns the value for the specified member.
int	getMin() Returns the minimum cardinality of the requirement.
int	hashCode()
boolean	isGreedy() Returns whether this requirement should cause extra installable units to be installed in order to satisfy it.
boolean	isMatch(IInstallableUnit candidate) Returns whether the provided capabilities of the given installable unit satisfy this requirement.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

MEMBER_FILTER

public static final java.lang.String MEMBER_FILTER

See Also:

Constant Field Values

MEMBER_MIN

public static final java.lang.String MEMBER_MIN

See Also:

Constant Field Values

MEMBER_MAX

public static final java.lang.String MEMBER_MAX

See Also:

Constant Field Values

MEMBER_GREEDY

public static final java.lang.String MEMBER_GREEDY

See Also:

Constant Field Values

MEMBER_MATCH

public static final java.lang.String MEMBER_MATCH

See Also:

Constant Field Values

filter

protected final IMatchExpression<IInstallableUnit> filter

matchExpression

protected final IMatchExpression<IInstallableUnit> matchExpression

greedy

protected final boolean greedy

min

protected final int min

max

protected final int max

description

protected final java.lang.String description

Constructor Detail

Requirement

public Requirement(IMatchExpression<IInstallableUnit> requirement,
                   IMatchExpression<IInstallableUnit> filter,
                   int min,
                   int max,
                   boolean greedy,
                   java.lang.String description)

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

getDescription

public java.lang.String getDescription()

Description copied from interface: IRequirement

Returns a textual description of this requirement.

Specified by:

getDescription in interface IRequirement

Returns:

a textual description of this requirement

getMin

public int getMin()

Description copied from interface: IRequirement

Returns the minimum cardinality of the requirement. That is, the minimum number of capabilities that must be provided that match this requirement before this requirement is considered fully satisfied. A minimum cardinality of 0 indicates that the requirement is optional.

Specified by:

getMin in interface IRequirement

Returns:

the minimum cardinality of this requirement

getMax

public int getMax()

Description copied from interface: IRequirement

Returns the maximum cardinality of the requirement. That is, the maximum number of capabilities that are permitted to be present that satisfy this requirement. A maximum cardinality of 0 indicates that there must not be any installable unit in the system that satisfies this requirement.

Specified by:

getMax in interface IRequirement

Returns:

the maximum cardinality of this requirement

isGreedy

public boolean isGreedy()

Description copied from interface: IRequirement

Returns whether this requirement should cause extra installable units to be installed in order to satisfy it.

Specified by:

isGreedy in interface IRequirement

Returns:

true if additional installable units should be installed to satisfy this requirement, and false otherwise

getFilter

public IMatchExpression<IInstallableUnit> getFilter()

Specified by:

getFilter in interface IRequirement

getMatches

public IMatchExpression<IInstallableUnit> getMatches()

Description copied from interface: IRequirement

Returns a boolean match expression that will return true for any IInstallableUnit that matches the requirement.

Specified by:

getMatches in interface IRequirement

Returns:

A boolean match expression for installable unit matching.

isMatch

public boolean isMatch(IInstallableUnit candidate)

Description copied from interface: IRequirement

Returns whether the provided capabilities of the given installable unit satisfy this requirement.

Specified by:

isMatch in interface IRequirement

Parameters:

candidate - the installable unit to check for matching capabilities

Returns:

true if the given installable unit satisfies this requirement, and false otherwise.

getMember

public java.lang.Object getMember(java.lang.String memberName)

Description copied from interface: IMemberProvider

Returns the value for the specified member. Implementers can rely on that the memberName is a string that has been internalized using String.intern().

Specified by:

getMember in interface IMemberProvider

Parameters:

memberName - The name of the member

Returns:

The member value.