org.apache.ambari.server.stack

Class ExtensionModule

java.lang.Object

org.apache.ambari.server.stack.BaseModule<ExtensionModule,ExtensionInfo>

org.apache.ambari.server.stack.ExtensionModule

All Implemented Interfaces:

StackDefinitionModule<ExtensionModule,ExtensionInfo>, Validable

public class ExtensionModule
extends BaseModule<ExtensionModule,ExtensionInfo>
implements Validable

Extension module which provides all functionality related to parsing and fully resolving extensions from the extension definition. An extension version is like a stack version but it contains custom services. Linking an extension version to the current stack version allows the cluster to install the custom services contained in the extension version.

Each extension node is identified by name and version, contains service child nodes and may extend a single parent extension.

Resolution of a extension is a depth first traversal up the inheritance chain where each extension node calls resolve on its parent before resolving itself. After the parent resolve call returns, all ancestors in the inheritance tree are fully resolved. The act of resolving the extension includes resolution of the services children of the extension as well as merging of other extension state with the fully resolved parent.

Because a service may explicitly extend another service in a extension outside of the inheritance tree, service child node resolution involves a depth first resolution of the extension associated with the services explicit parent, if any. This follows the same steps defined above fore extension node resolution. After the services explicit parent is fully resolved, the services state is merged with it's parent.

If a cycle in a extension definition is detected, an exception is thrown from the resolve call.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	valid validity flag

Fields inherited from class org.apache.ambari.server.stack.BaseModule

moduleState

Constructor Summary

Constructors

Constructor and Description
ExtensionModule(ExtensionDirectory extensionDirectory, StackContext stackContext) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addError(String error)
void	addErrors(Collection<String> errors)
void	finalizeModule() Lifecycle even which is called when the associated stack has been fully resolved.
Collection<String>	getErrors()
ExtensionDirectory	getExtensionDirectory() Get the associated extension directory.
String	getId() Obtain the id of the module.
ExtensionInfo	getModuleInfo() Obtain the associated module information.
Map<String,ServiceModule>	getServiceModules()
boolean	isDeleted() Determine whether the module has been marked for deletion.
boolean	isValid()
void	resolve(ExtensionModule parentModule, Map<String,StackModule> allStacks, Map<String,ServiceModule> commonServices, Map<String,ExtensionModule> extensions) Fully resolve the extension.
void	setValid(boolean valid)

Methods inherited from class org.apache.ambari.server.stack.BaseModule

finalizeChildModules, getModuleState, mergeChildModules

Methods inherited from class java.lang.Object

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

Field Detail

valid

protected boolean valid

validity flag

Constructor Detail

ExtensionModule

public ExtensionModule(ExtensionDirectory extensionDirectory,
                       StackContext stackContext)

Constructor.

Parameters:

extensionDirectory - represents extension directory

stackContext - general stack context

Method Detail

getServiceModules

public Map<String,ServiceModule> getServiceModules()

resolve

public void resolve(ExtensionModule parentModule,
                    Map<String,StackModule> allStacks,
                    Map<String,ServiceModule> commonServices,
                    Map<String,ExtensionModule> extensions)
             throws org.apache.ambari.server.AmbariException

Fully resolve the extension. See extension resolution description in the class documentation. If the extension has a parent, this extension will be merged against its fully resolved parent if one is specified. Merging applies to all extension state including child service and configuration modules. Services may extend a service in another version in the same extension hierarchy or may explicitly extend a service in a different hierarchy.

Specified by:

resolve in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Parameters:

parentModule - not used. Each extension determines its own parent since extensions don't have containing modules

allStacks - all stacks modules contained in the stack definition

commonServices - all common services

extensions - all extensions

Throws:

org.apache.ambari.server.AmbariException - if an exception occurs during extension resolution

getModuleInfo

public ExtensionInfo getModuleInfo()

Description copied from interface: StackDefinitionModule

Obtain the associated module information.

Specified by:

getModuleInfo in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Returns:

associated module information

isDeleted

public boolean isDeleted()

Description copied from interface: StackDefinitionModule

Determine whether the module has been marked for deletion.

Specified by:

isDeleted in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Returns:

true if the module is marked for deletion; otherwise false

getId

public String getId()

Description copied from interface: StackDefinitionModule

Obtain the id of the module.

Specified by:

getId in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Returns:

module id

finalizeModule

public void finalizeModule()

Description copied from interface: StackDefinitionModule

Lifecycle even which is called when the associated stack has been fully resolved.

Specified by:

finalizeModule in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Overrides:

finalizeModule in class BaseModule<ExtensionModule,ExtensionInfo>

getExtensionDirectory

public ExtensionDirectory getExtensionDirectory()

Get the associated extension directory.

Returns:

associated extension directory

isValid

public boolean isValid()

Specified by:

isValid in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Specified by:

isValid in interface Validable

Returns:

valid xml flag

setValid

public void setValid(boolean valid)

Specified by:

setValid in interface StackDefinitionModule<ExtensionModule,ExtensionInfo>

Specified by:

setValid in interface Validable

Parameters:

valid - set validity flag

getErrors

public Collection<String> getErrors()

Specified by:

getErrors in interface Validable

addError

public void addError(String error)

Specified by:

addError in interface Validable

addErrors

public void addErrors(Collection<String> errors)

Specified by:

addErrors in interface Validable