public class IlvLabelLayoutLabelProperty extends IlvNamedProperty
IlvLabelLayoutLabelProperty
allows you to store
the settings of an instance of IlvLabelLayout
for an
individual label as a named property in the label. This is used by
IlvDefaultLabelingModel.saveParametersToNamedProperties(IlvLabelLayout,
boolean)
which is an auxiliary to be used before IlvManager.write(IlvOutputStream)
if you want to store layout
parameter settings in .ivl
files.
If you create your own subclass of IlvLabelLayout
and
want to save the layout parameters of your subclass for individual
labels in .ivl
files, you need to create a subclass of
this class. The subclass must provide a constructor with your
IlvLabelLayout
subclass and the label as input, and
transfer the layout parameters of the label from the input layout to
the property. It must also override the transfer
method
to transfer the layout parameters from the property back to the layout
instance.
Further information about subclassing can be found in the
documentation of IlvNamedProperty
.
As an example, assume that your subclass MyLayout
of
IlvLabelLayout
has a string parameter for each label that
can be accessed by getMyParameter
and set by
setMyParameter
. You can create a named property that can
store this parameter in the following way:
public class MyLayoutLabelProperty extends IlvLabelLayoutLabelProperty { String myParameter; public MyLayoutLabelProperty( String name, MyLayout layout, IlvGraphic label, boolean withDefaults) { super(name, layout, label, withDefaults); this.myParameter = layout.getMyParameter(label); } public MyLayoutLabelProperty(MyLayoutLabelProperty source) { super(source); this.myParameter = source.myParameter; } public MyLayoutLabelProperty(IlvInputStream stream) throws IOException, IlvReadFileException { super(stream); try { this.myParameter = stream.readString("myParameter"); } catch (IlvFieldNotFoundException e) { this.myParameter = myParameterDefaultValue; } } public IlvNamedProperty copy() { return new MyLayoutLabelProperty(this); } public void write(IlvOutputStream stream) throws IOException { super.write(stream); stream.write("myParameter", this.myParameter); } public void transfer(IlvLabelLayout layout, IlvGraphic label) { super.transfer(layout, label); ((MyLayout)layout).setMyParameter(label, this.myParameter); } public boolean isPersistent() { // this will catch the case that omitDefaults is false if (super.isPersistent()) return true; // in case omitDefaults is true: if (this.myParameter != myParameterDefaultValue) return true; return false; } }Note that
MyLayout
must override IlvLabelLayout.createLayoutLabelProperty(String, IlvGraphic, boolean)
to return an instance of your new class
MyLayoutLabelProperty
.
Constructor and Description |
---|
IlvLabelLayoutLabelProperty(IlvInputStream stream)
Creates a new
IlvLabelLayoutLabelProperty from an
IlvInputStream . |
IlvLabelLayoutLabelProperty(IlvLabelLayoutLabelProperty source)
Creates a new
IlvLabelLayoutLabelProperty by copying an
existing one. |
IlvLabelLayoutLabelProperty(String name,
IlvLabelLayout layout,
IlvGraphic label,
boolean withDefaults)
Creates a new
IlvLabelLayoutLabelProperty that stores
layout parameter settings of the layout for the
label . |
Modifier and Type | Method and Description |
---|---|
IlvNamedProperty |
copy()
Copies the named property.
|
void |
dispose(IlvDefaultLabelingModel model)
Disposes of the property and releases any resources that it is using.
|
protected IlvLabelLayout |
getLayout()
Returns the layout instance that created this property.
|
boolean |
isPersistent()
Returns
true if the property must be saved to an
.ivl file. |
protected boolean |
isWritten(IlvGraphic label)
Returns
true if the writing of the input label was
completed. |
protected boolean |
omitDefaults()
Returns
true if the layout property is not persistent
when all stored parameter values are default values. |
void |
transfer(IlvLabelLayout layout,
IlvGraphic label)
Transfers the layout parameter settings stored in this named property
back to the input layout for the input label.
|
void |
write(IlvOutputStream stream)
Writes the property to the output stream.
|
getName
public IlvLabelLayoutLabelProperty(String name, IlvLabelLayout layout, IlvGraphic label, boolean withDefaults)
IlvLabelLayoutLabelProperty
that stores
layout parameter settings of the layout
for the
label
.name
- The name of the property.layout
- The layout instance to be stored.label
- The label whose layout parameters are to be stored.withDefaults
- If true
, the layout property is always
persistent. If false
, it is persistent only if
nondefault parameter settings exist (that is, if the the property
is saved to an .ivl
file, the default parameter
settings are not saved).public IlvLabelLayoutLabelProperty(IlvLabelLayoutLabelProperty source)
IlvLabelLayoutLabelProperty
by copying an
existing one.source
- The origin of the copy.public IlvLabelLayoutLabelProperty(IlvInputStream stream) throws IOException, IlvReadFileException
IlvLabelLayoutLabelProperty
from an
IlvInputStream
.stream
- The input stream from which the property must be read.IlvReadFileException
- if an error occurs while reading.IOException
protected IlvLabelLayout getLayout()
IlvInputStream
, it
returns null
.protected boolean omitDefaults()
true
if the layout property is not persistent
when all stored parameter values are default values. Returns
false
if the layout property is persistent independent
of default values. If the property was created by reading from
IlvInputStream
, it returns false
.public IlvNamedProperty copy()
copy
in class IlvNamedProperty
public boolean isPersistent()
true
if the property must be saved to an
.ivl
file.isPersistent
in class IlvNamedProperty
protected boolean isWritten(IlvGraphic label)
true
if the writing of the input label was
completed.
If customers need to subclass this class, this auxiliary can be used
inside the implementation of the write
method only. For
instance, it can be used if information must be written depending on
whether another label has already been written.
label
- A label of the same manager.true
if the label has been written before this
property.write(IlvOutputStream)
public void write(IlvOutputStream stream) throws IOException
write
in interface IlvPersistentObject
write
in class IlvNamedProperty
stream
- The output stream.IOException
- standard IO error.public void transfer(IlvLabelLayout layout, IlvGraphic label)
layout
- The layout instance whose parameters are to be recovered
from this named property.label
- The label whose layout parameters are to be recovered from
this named property.public void dispose(IlvDefaultLabelingModel model)
model
- The labeling model.IlvDefaultLabelingModel.loadParametersFromNamedProperties(IlvLabelLayout)
,
IlvDefaultLabelingModel.removeParametersFromNamedProperties()
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