/*
 Copyright 2008-2013 Gephi
 Authors : Mathieu Bastian <mathieu.bastian@gephi.org>
 Website : http://www.gephi.org

 This file is part of Gephi.

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 Copyright 2013 Gephi Consortium. All rights reserved.

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 or /cddl-1.0.txt and /gpl-3.0.txt. See the License for the
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 */

package org.gephi.appearance.api;

import org.gephi.appearance.spi.Transformer;
import org.gephi.appearance.spi.TransformerUI;
import org.gephi.graph.api.Element;
import org.gephi.graph.api.Graph;

/**
 * Functions represent the various transformations that can be applied to the
 * graph elements. Each function is specific to an element class (i.e. nodes or
 * edges), to a specific transformer and to a specific source (e.g. a ranking or
 * a partition).
 * <p>
 * This interface has sub-interfaces specific to the type of function.
 */
public interface Function {

    /**
     * Transforms the given element.
     *
     * @param element element to transform
     */
    void transform(Element element);

    /**
     * Transforms all the given elements.
     *
     * @param elementIterable element iterable to tranform
     */
    void transformAll(Iterable<? extends Element> elementIterable);

    /**
     * Returns the transformer associated with this function.
     *
     * @param <T> transformer class
     * @return transformer
     */
    <T extends Transformer> T getTransformer();

    /**
     * Returns the transformer user interface associated with this function.
     *
     * @return transformer UI or null if not found
     */
    TransformerUI getUI();

    /**
     * Returns true if this function is a simple function.
     * <p>
     * If true, this instance can be casted to <code>SimpleFunction</code>.
     *
     * @return true if partition, false otherwise
     */
    boolean isSimple();

    /**
     * Returns true if this function is based on attribute column.
     * <p>
     * If true, this instance can be casted to <code>AttributeFunction</code>.
     *
     * @return true if attribute, false otherwise
     */
    boolean isAttribute();

    /**
     * Returns true if this function is a ranking function.
     * <p>
     * If true, this instance can be casted to <code>RankingFunction</code>.
     *
     * @return true if ranking, false otherwise
     */
    boolean isRanking();

    /**
     * Returns true if this function is a partition function.
     * <p>
     * If true, this instance can be casted to <code>PartitionFunction</code>.
     *
     * @return true if partition, false otherwise
     */
    boolean isPartition();

    /**
     * Returns the element class this function will be applied to.
     *
     * @return element class
     */
    Class<? extends Element> getElementClass();

    /**
     * Returns the graph this function is being applied on.
     *
     * @return graph
     */
    Graph getGraph();

    /**
     * Returns the model this function belongs to.
     *
     * @return model
     */
    AppearanceModel getModel();

    /**
     * Returns true if the underlying partition or ranking changed its boundaries or values since last time checked.
     *
     * @return true if changed, false otherwise
     */
    boolean hasChanged();

    /**
     * Returns the function's unique identifier.
     *
     * @return function id
     */
    String getId();

    /**
     * Returns true if the function is valid. A function may not be valid if the underlying column has been removed for instance.
     *
     * @return true if valid, false otherwise
     */
    boolean isValid();
}
