y.io.graphml.output
Class AbstractOutputHandler

java.lang.Object
  y.io.graphml.output.AbstractOutputHandler

All Implemented Interfaces:

java.util.EventListener, OutputHandler, OutputHandlerProvider

Direct Known Subclasses:

AbstractDataProviderOutputHandler, AbstractWriteNodePortHandler, EdgeLayoutOutputHandler, NodeLayoutOutputHandler, PostprocessorOutputHandler, WriteEdgeRealizerHandler, WriteNodeRealizerHandler

public abstract class AbstractOutputHandler
extends java.lang.Object
implements OutputHandler, OutputHandlerProvider

Convenience abstract base implementation of the OutputHandler interface.

Since this class also implements the OutputHandlerProvider interface, it can be registered directly with GraphMLHandler.addOutputHandlerProvider(y.io.graphml.output.OutputHandlerProvider)

Constructor Summary

protected	AbstractOutputHandler() Initializes a new instance of the AbstractOutputHandler class.
protected	AbstractOutputHandler(java.lang.String name, KeyScope scope, KeyType type) Initializes a new instance of the AbstractOutputHandler class

Method Summary

void	addNameToKeyDefinition(java.lang.String name) Adds the name to the key definition.
void	addScopeToKeyDefinition(KeyScope scope) Adds the scope to the key definition.
void	addTypeToKeyDefinition(KeyType type) Adds the key type to the key definition.
void	addUriToKeyDefinition(java.lang.String uri) Adds an optional uri to the key definition.
java.util.Collection	getDataTagAttributes() Returns XML all attributes of the data element.
java.lang.Object	getDefaultValue() Gets the default value.
java.util.Collection	getKeyDefinitionAttributes() Returns all XML attributes of the key element.
WritePrecedence	getPrecedence() Gets the write precedence for the handler.
KeyScope	getScope() Gets the KeyScope where this handler should register itself.
java.util.Set	getValidScopes() Allows to restrict the scopes where the handler is used, if the handler is registered to KeyScope.ALL.
protected abstract java.lang.Object	getValue(GraphMLWriteContext context, java.lang.Object key) Callback method that obtains the data for the given key.
boolean	hasDefaultValueAssigned() Gets a value indicating whether a default value has been assigned.
boolean	isDefaultValue(GraphMLWriteContext ctx) Determines whether in the current context, the value is the default value and therefore no data element needs to be written.
protected boolean	isValidScope(GraphMLWriteContext ctx) Checks whether the current handler is called in a scope that is valid. wrt getValidScopes()
boolean	isWriteKeyDefault() Gets a value indicating whether to write the key default.
void	onQueryOutputHandler(QueryOutputHandlersEvent event) Allows this instance to register itself as an OutputHandler.
void	setDefaultValue(java.lang.Object value) Sets the default value.
protected void	setDefaultValueAssigned(boolean value) Sets a value indicating whether a default value has been assigned.
void	setPrecedence(WritePrecedence value) Sets the write precedence for the handler.
void	setScope(KeyScope scope) Sets the KeyScope where this handler should register itself.
void	setValidScopes(java.util.Set value) Allows to restrict the scopes where the handler is used, if the handler is registered to KeyScope.ALL.
void	setWriteKeyDefault(boolean value) Sets a value indicating whether to write the key default.
void	writeKeyDefinitionContent(GraphMLWriteContext ctx) Writes the contents of the key definition.
void	writeValue(GraphMLWriteContext ctx) Actually writes the value for the current context.
protected abstract void	writeValueCore(GraphMLWriteContext context, java.lang.Object data) Core write that performs the actual writing of the data.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractOutputHandler

protected AbstractOutputHandler()

Initializes a new instance of the AbstractOutputHandler class.

AbstractOutputHandler

protected AbstractOutputHandler(java.lang.String name,
                                KeyScope scope,
                                KeyType type)

Initializes a new instance of the AbstractOutputHandler class

Parameters:

name - The name to use for the key definition.

scope - The scope, if this is KeyScope.GRAPHML, the getValidScopes() property is initialized to contain exactly that scope.

type - The type to use for the key definition.

Method Detail

getScope

public KeyScope getScope()

Gets the KeyScope where this handler should register itself.

Returns:

the KeyScope where this handler should register itself.

See Also:

onQueryOutputHandler(QueryOutputHandlersEvent), setScope(y.io.graphml.KeyScope)

setScope

public void setScope(KeyScope scope)

Sets the KeyScope where this handler should register itself.

Parameters:

scope - the KeyScope where this handler should register itself.

See Also:

onQueryOutputHandler(QueryOutputHandlersEvent), getScope()

onQueryOutputHandler

public void onQueryOutputHandler(QueryOutputHandlersEvent event)
                          throws GraphMLWriteException

Allows this instance to register itself as an OutputHandler.

This implementation registers the current instance on event if a KeyScope has been specified either with AbstractOutputHandler(String, y.io.graphml.KeyScope, y.io.graphml.KeyType) or setScope(y.io.graphml.KeyScope)

Specified by:

onQueryOutputHandler in interface OutputHandlerProvider

Parameters:

event - Event that contains all data relevant for handler setup.

Throws:

GraphMLWriteException - if a problem occurs during serialization.

addNameToKeyDefinition

public void addNameToKeyDefinition(java.lang.String name)

Adds the name to the key definition.

Parameters:

name - The name of the key element.

addUriToKeyDefinition

public void addUriToKeyDefinition(java.lang.String uri)

Adds an optional uri to the key definition.

By default, no URI is set.

Parameters:

uri - The uri of the key element.

addTypeToKeyDefinition

public void addTypeToKeyDefinition(KeyType type)

Adds the key type to the key definition.

Parameters:

type - The type of the key element.

addScopeToKeyDefinition

public void addScopeToKeyDefinition(KeyScope scope)

Adds the scope to the key definition.

Note that the official graphml schema does not support the KeyScope.GRAPHML so this implementation will silently ignore this which will result in KeyScope.ALL implicitly being defined.

Parameters:

scope - The scope of the key element.

getDefaultValue

public java.lang.Object getDefaultValue()

Gets the default value.

Returns:

The default value of the attribute.

See Also:

setDefaultValue(Object)

setDefaultValue

public void setDefaultValue(java.lang.Object value)

Sets the default value.

Setting this value also sets the hasDefaultValueAssigned() property.

Parameters:

value - The default value of the attribute.

See Also:

getDefaultValue()

hasDefaultValueAssigned

public boolean hasDefaultValueAssigned()

Gets a value indicating whether a default value has been assigned.

Returns:

true if a default value has been assigned; false otherwise.

See Also:

setDefaultValueAssigned(boolean)

setDefaultValueAssigned

protected void setDefaultValueAssigned(boolean value)

Sets a value indicating whether a default value has been assigned.

Parameters:

value - true if a default value has been assigned; false otherwise.

See Also:

setDefaultValueAssigned(boolean)

getPrecedence

public WritePrecedence getPrecedence()

Gets the write precedence for the handler.

Specified by:

getPrecedence in interface OutputHandler

Returns:

The write precedence.

See Also:

setPrecedence(WritePrecedence)

setPrecedence

public void setPrecedence(WritePrecedence value)

Sets the write precedence for the handler.

Parameters:

value - The write precedence.

See Also:

getPrecedence()

getKeyDefinitionAttributes

public java.util.Collection getKeyDefinitionAttributes()

Returns all XML attributes of the key element.

Specified by:

getKeyDefinitionAttributes in interface OutputHandler

Returns:

All attributes of the key element.

See Also:

addNameToKeyDefinition(String), addScopeToKeyDefinition(y.io.graphml.KeyScope), addTypeToKeyDefinition(y.io.graphml.KeyType), addUriToKeyDefinition(String)

getDataTagAttributes

public java.util.Collection getDataTagAttributes()

Returns XML all attributes of the data element.

By default, this collection is empty.

Specified by:

getDataTagAttributes in interface OutputHandler

Returns:

All attributes of the data element.

isDefaultValue

public boolean isDefaultValue(GraphMLWriteContext ctx)
                       throws GraphMLWriteException

Determines whether in the current context, the value is the default value and therefore no data element needs to be written.

This implementation will return false if no hasDefaultValueAssigned(). Otherwise it will use getValue(y.io.graphml.output.GraphMLWriteContext,Object) and compare the result with the getDefaultValue() to determine whether they are equal and therefore no data needs to be written.

Specified by:

isDefaultValue in interface OutputHandler

Parameters:

ctx - The context.

Returns:

true if for the current context the default value applies and therefore no data element needs to be written.

Throws:

GraphMLWriteException

See Also:

hasDefaultValueAssigned(), getDefaultValue()

isValidScope

protected boolean isValidScope(GraphMLWriteContext ctx)

Checks whether the current handler is called in a scope that is valid. wrt getValidScopes()

Parameters:

ctx - The current write context.

Returns:

true iff the current scope in which the handler is called is valid wrt getValidScopes().

See Also:

getValidScopes(), SerializationProperties.CURRENT_KEY_SCOPE

getValidScopes

public java.util.Set getValidScopes()

Allows to restrict the scopes where the handler is used, if the handler is registered to KeyScope.ALL.

By default the collection contains KeyScope.ALL, which means the set of valid scopes is not restricted further.

Returns:

A set of actually valid scopes for KeyScope.ALL

See Also:

isValidScope(GraphMLWriteContext), setValidScopes(java.util.Set)

setValidScopes

public void setValidScopes(java.util.Set value)

Allows to restrict the scopes where the handler is used, if the handler is registered to KeyScope.ALL.

By default the collection contains the KeyScope.ALL, which means the set of valid scopes is not restricted further.

Parameters:

value - A set of actually valid scopes for KeyScope.ALL

See Also:

isValidScope(GraphMLWriteContext), getValidScopes()

writeValue

public void writeValue(GraphMLWriteContext ctx)
                throws GraphMLWriteException

Actually writes the value for the current context.

This method will use getValue(y.io.graphml.output.GraphMLWriteContext,Object) to obtain the data and delegate to writeValueCore(y.io.graphml.output.GraphMLWriteContext,Object) to perform the actual serialization.

Specified by:

writeValue in interface OutputHandler

Parameters:

ctx - The context.

Throws:

GraphMLWriteException

writeKeyDefinitionContent

public void writeKeyDefinitionContent(GraphMLWriteContext ctx)
                               throws GraphMLWriteException

Writes the contents of the key definition.

Depending on whether setWriteKeyDefault(boolean) is enabled and hasDefaultValueAssigned() is true, this method will write the GraphML 'default' element and use writeValueCore(y.io.graphml.output.GraphMLWriteContext,Object) to serialize the getDefaultValue().

Specified by:

writeKeyDefinitionContent in interface OutputHandler

Parameters:

ctx - The context.

Throws:

GraphMLWriteException

setWriteKeyDefault

public void setWriteKeyDefault(boolean value)

Sets a value indicating whether to write the key default.

Parameters:

value - true if the key default should be written at all.

See Also:

isWriteKeyDefault(), writeKeyDefinitionContent(GraphMLWriteContext)

isWriteKeyDefault

public boolean isWriteKeyDefault()

Gets a value indicating whether to write the key default.

Returns:

true if the key default should be written; false otherwise.

See Also:

setWriteKeyDefault(boolean), writeKeyDefinitionContent(GraphMLWriteContext)

writeValueCore

protected abstract void writeValueCore(GraphMLWriteContext context,
                                       java.lang.Object data)
                                throws GraphMLWriteException

Core write that performs the actual writing of the data.

Parameters:

context - The context.

data - The data.

Throws:

GraphMLWriteException

getValue

protected abstract java.lang.Object getValue(GraphMLWriteContext context,
                                             java.lang.Object key)
                                      throws GraphMLWriteException

Callback method that obtains the data for the given key.

Parameters:

context - The context.

key - The key.

Returns:

The data that is associated with the key.

Throws:

GraphMLWriteException