package com.onaro.util.jfc.grouping;

/**
 * A node in the navigation tree of the grouping table. The nodes are created
 * by the grouping process which also cause them to calculate the summary. Also
 * nodes are used when displaying the navigation tree.
 */
public interface Node {

    /**
     * Gets the name of this node. The name is displayed to the user at the grouping column.
     * @return the name of this node
     */
    public Object getName();

    /**
     * Gets the identifier of this node. Used to distinguish brother nodes.
     * @return the identifier of this node
     */
    public Object getIdentifier();

    /**
     * Gets the number of childs this node has
     * @return the number of childs
     */
    public int getChildCount();

    /**
     * Gets the total number of descendant leafs of this node.
     * @return the sum of all the leafs below this node
     */
    public int getDescendantLeafCount();

    /**
     * Get a child of this node by its index.
     * @param index the index of the requested child
     * @return the child or null if it doesn't exist
     */
    public Node getChild(int index);

    /**
     * Gets a child of this node by its identifier.
     * @param identifier identifies the requested child
     * @return the child or null if it doesn't exist
     */
    public Node getChildByIdentifier(Object identifier);

    /**
     * Gets the value for the requested column.
     * @param column requested column number, 0 is the navigtion column and 1,2,...
     *        are columns 0,1,... of the encapsulated table-model
     * @return the value at the requested column
     */
    public Object getValueAt(int column);

    /**
     * Used by the summarizers to set the values of columns of group nodes.
     * @param column the column to set the value in
     * @param value the value
     */
    public void setValueAt(int column, Object value);

    /**
     * Gets the value of this node for the requested criterion (column).
     * @param criterion the grouping criterion number as an index in the
     *        {@link GroupingModel#groupingCriteria}
     * @return the value that is common to all the rows in this group and sub-groups
     *         for the requested criterion
     */
    public Object getCriterionValue(int criterion);

    /**
     * Adds a child to this node.
     * @param depth the depth of this node in the hierarchy, used for finding the
     *        grouping criterion to use
     * @param child the child to add
     */
    public void addChild(int depth, Node child);

    /**
     * Update the summary of this node and all its descendant.
     */
    public void updateSummary();

    /**
     * Ask the node to recursively sort its descendants. First the node is required
     * to ask each of its descendants to sort and only than it should sort itself too.
     */
    public void doSort();

    /**
     * Determine if a cell in a node is editable by the user
     */
    public boolean isCellEditable(int column);
}