/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* LabelsMetaData.java
* Copyright (C) 2009-2010 Aristotle University of Thessaloniki, Thessaloniki, Greece
*/
package mulan.data;
import java.util.Set;
/**
* Represents meta data about label attributes and their structure.
* The labels can be organized in hierarchical structure. If no hierarchy
* is defined between labels, they are stored in a flat structure.
* This means all labels are represented as root {@link LabelNode} element.
*
* @author Jozef Vilcek
*/
public interface LabelsMetaData {
/**
* Gets the unmodifiable {@link Set} of root {@link LabelNode}
* nodes of label attributes hierarchy.
*
* @return the {@link Set} of root nodes.
*/
Set<LabelNode> getRootLabels();
/**
* Gets the {@link LabelNode} specified by label name. The name is unique identifier
* of the node and corresponds to label attribute in the data set.
* If {@link LabelNode} for given label name does not exists, <code>null</code> is returned.
*
* @param labelName the name of label of which the node should be retrieved
* @return the {@link LabelNode} for specified label of <code>null</code>
* if {@link LabelNode} does not exists for specified label name
*/
LabelNode getLabelNode(String labelName);
/**
* Gets the names of all labels. The label name is a unique identifier among all
* labels in the meta data.
*
* @return the names of all labels.
*/
Set<String> getLabelNames();
/**
* Determines if {@link LabelsMetaData} contains a label with specified name.
*
* @param labelName the label name
* @return <code>true</code> if meta data contains the given label name;
* <code>false</code> otherwise.
*/
boolean containsLabel(String labelName);
/**
* Determines if there is a hierarchy defined between labels. If not, all labels are
* represented as root {@link LabelNode} nodes.
*
* @return <code>true</code> if there is hierarchy defined between labels;
* <code>false</code> otherwise.
*/
boolean isHierarchy();
/**
* Gets the total number of {@link LabelNode} nodes.
* @return total number of {@link LabelNode} nodes
*/
int getNumLabels();
/**
* Returns a deep copy of the {@link LabelsMetaDataImpl} instance.
* @return a deep copy of the {@link LabelsMetaDataImpl} instance
*/
LabelsMetaData clone();
}