META-INF.modules.java.desktop.classes.javax.imageio.metadata.IIOMetadataController Maven / Gradle / Ivy
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package javax.imageio.metadata;
/**
* An interface to be implemented by objects that can determine the
* settings of an {@code IIOMetadata} object, either by putting
* up a GUI to obtain values from a user, or by other means. This
* interface merely specifies a generic {@code activate} method
* that invokes the controller, without regard for how the controller
* obtains values (i.e., whether the controller puts up a GUI
* or merely computes a set of values is irrelevant to this
* interface).
*
* Within the {@code activate} method, a controller obtains
* initial values by querying the {@code IIOMetadata} object's
* settings, either using the XML DOM tree or a plug-in specific
* interface, modifies values by whatever means, then modifies the
* {@code IIOMetadata} object's settings, using either the
* {@code setFromTree} or {@code mergeTree} methods, or a
* plug-in specific interface. In general, applications may expect
* that when the {@code activate} method returns
* {@code true}, the {@code IIOMetadata} object is ready for
* use in a write operation.
*
*
Vendors may choose to provide GUIs for the
* {@code IIOMetadata} subclasses they define for a particular
* plug-in. These can be set up as default controllers in the
* corresponding {@code IIOMetadata} subclasses.
*
*
Alternatively, an algorithmic process such as a database lookup
* or the parsing of a command line could be used as a controller, in
* which case the {@code activate} method would simply look up or
* compute the settings, call methods on {@code IIOMetadata} to
* set its state, and return {@code true}.
*
* @see IIOMetadata#setController
* @see IIOMetadata#getController
* @see IIOMetadata#getDefaultController
* @see IIOMetadata#hasController
* @see IIOMetadata#activateController
*
*/
public interface IIOMetadataController {
/**
* Activates the controller. If {@code true} is returned,
* all settings in the {@code IIOMetadata} object should be
* ready for use in a write operation. If {@code false} is
* returned, no settings in the {@code IIOMetadata} object
* will be disturbed (i.e., the user canceled the
* operation).
*
* @param metadata the {@code IIOMetadata} object to be modified.
*
* @return {@code true} if the {@code IIOMetadata} has been
* modified, {@code false} otherwise.
*
* @exception IllegalArgumentException if {@code metadata} is
* {@code null} or is not an instance of the correct class.
*/
boolean activate(IIOMetadata metadata);
}