[FELIX-6258] Implement equals() and hashCode() for org.apache.felix.utils.resource.CapabilityImpl in Felix util

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: utils-1.11.4
• Component/s: Felix Commons
• Assignee: Unassigned
• Reporter: Tuan
• Created: 15/Apr/20 04:46
• Updated: 15/Apr/20 04:50

Description

Hi Felix devs,

I'm using karaf 4.2.7 which include felix util 1.11.2

There is an interface org.osgi.resource.Capability with these methods

/**
                * Compares this {@code Capability} to another {@code
Capability}.
                *
                 * <p>
                * This {@code Capability} is equal to another {@code
Capability} if they
                * have the same namespace, directives and attributes
and are declared by
                * the same resource.
                *
                * @param obj The object to compare against this {@code
Capability}.
                * @return {@code true} if this {@code Capability} is
equal to the other
                *         object; {@code false} otherwise.
                */
                boolean equals(Object obj);


                /**
                * Returns the hashCode of this {@code Capability}.
                *
                * @return The hashCode of this {@code Capability}.
                */

                int hashCode();

And we also implement above interface via org.apache.felix.utils.resource.CapabilityImpl but this class does not implement equals() and hashCode().

This will be a problem when we have the same bundles expose the same package, org.apache.felix.utils.resource.CapabilitySet#addCapability will add dupplicate capability.

E.g. I have a feature class named "my-feature" and this feature contains

<repository>mvn:org.apache.cxf.karaf/apache-cxf/${cxf.version}/xml/features</repository>

<feature name="my-feature">
    <bundle>mvn:org.apache.cxf/cxf-core/${cxf.version}</bundle>
    ... my other bundles ...
 </feature>

During startup time, felix resolve export-packages from cxf-core and found that cxf-core packages are exposed by 2 bundles (first one from
cxf-core in repository and the other from my-feature).

{ResourceImpl@24398} "org.apache.cxf.cxf-core/3.3.4" ->{Subsystem@24381} "root#my-feature"
{ResourceImpl@24423} "org.apache.cxf.cxf-core/3.3.4" ->{Subsystem@24414} "root#cxf-core-3.3.4"

 

+ export packages from cxf-core in repository.

{CapabilityImpl@7156}
"[org.apache.cxf.cxf-core/3.3.4]osgi.wiring.package; version:Version=3.3.4;bundle-symbolic-name=org.apache.cxf.cxf-core;bundle-version:Version=3.3.4;osgi.wiring.package=org.apache.cxf.annotations" ->{RequirementImpl@8400} "[org.apache.cxf.cxf-core/3.3.4]
 osgi.wiring.package;filter:="(osgi.wiring.package=org.apache.cxf.annotations)""

{CapabilityImpl@7157}
"[org.apache.cxf.cxf-core/3.3.4]osgi.wiring.package; version:Version=3.3.4;bundle-symbolic-name=org.apache.cxf.cxf-core;bundle-version:Version=3.3.4;
 osgi.wiring.package=org.apache.cxf.attachment" ->{RequirementImpl@8401} "[org.apache.cxf.cxf-core/3.3.4]
 osgi.wiring.package;filter:="(osgi.wiring.package=org.apache.cxf.attachment)""

 

+ export packages from cxf-core in my-feature.

{CapabilityImpl@9196}
"[org.apache.cxf.cxf-core/3.3.4] osgi.wiring.package; version:Version=3.3.4; bundle-symbolic-name=org.apache.cxf.cxf-core;bundle-version:Version=3.3.4;osgi.wiring.package=org.apache.cxf.annotations" ->{RequirementImpl@8142} "[org.apache.cxf.cxf-core/3.3.4]
 osgi.wiring.package;filter:="(osgi.wiring.package=org.apache.cxf.annotations)""

{CapabilityImpl@9197}
"[org.apache.cxf.cxf-core/3.3.4]osgi.wiring.package; version:Version=3.3.4;bundle-symbolic-name=org.apache.cxf.cxf-core;bundle-version:Version=3.3.4;
 osgi.wiring.package=org.apache.cxf.attachment" ->{RequirementImpl@8146} "[org.apache.cxf.cxf-core/3.3.4]
 osgi.wiring.package;filter:="(osgi.wiring.package=org.apache.cxf.attachment)""

 

Due to this, these export-package from cxf-core will be moved to m_substPermutations in org.apache.felix.resolver.ResolverImpl via
org.apache.felix.resolver.ResolverImpl.ResolveSession#addPermutation.

If m_substPermutations grow huge, this will be a performence issue as each permutation keep ~ 1mb.

Is there any reason why are we not implement equals() and hashCode() in Capability?

I think if we implement these methods, the size of CapabilitySet can be reduced because we don't add duplicate Capability.

Thanks,
Tuan.