core/org.eclipse.statet.rj.data/src/org/eclipse/statet/rj/data/RArray.java

/*=============================================================================#
 # Copyright (c) 2009, 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.rj.data;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;


/**
 * An R object is of the type {@link RObject#TYPE_ARRAY array}, if it is an R
 * data object of an "atomic" mode with a dimension attribute (<code>dim</code>).
 * Such an R array object is represented by an instance of this interface.
 * <p>
 * The real data is stored in a {@link RStore} accessible by {@link #getData()}.
 * An index for the one-dimensional data store can be computed from an
 * index tuple relative to the dimension of the object using the methods
 * {@link RDataUtils#getDataIdx(int[], int[])}.</p>
 * <p>
 * Also an S3 object based on a such a data object is of the type {@link RObject#TYPE_ARRAY array}.
 * Whereas a S4 object is never directly of this type even the object simulates an
 * array in R. Such an object is of the type {@link RObject#TYPE_S4OBJECT S4 object},
 * and implements {@link RS4Object} with an object of the type {@link RObject#TYPE_ARRAY array}
 * as data slot.</p>
 * <p>
 * The complementary type for objects without dimension attribute is the type
 * {@link RObject#TYPE_VECTOR vector} and the interface {@link RVector}.</p>
 * 
 * @see RDataUtils#getDataIdx(int[], int[])
 * @see RDataUtils#getDataIdxs(int[], int, int)
 * @param <TData> the type of the data store
 */
@NonNullByDefault
public interface RArray<TData extends RStore<?>> extends RObject {
	
	
	/**
	 * Returns the length of the object. The length of an {@link RObject#TYPE_ARRAY array}
	 * is the count of all data values, the product of its dimensions.
	 * 
	 * @return the length
	 */
	@Override
	long getLength();
	
	/**
	 * Returns the dimension of this array. This corresponds to the R dimension
	 * attribute (<code>dim</dim>) respectively the R <code>dim</code> function.
	 * 
	 * @return the dimension of this array
	 */
	RIntegerStore getDim();
	
	/**
	 * Returns the names for the dimensions of the array. This corresponds to
	 * the names of the R attribute <code>dimnames</code> respectively of the R function
	 * <code>dimnames(object)</code>. That means it is equivalent to the R command
	 * <code>names(dimnames(object))</code>. The names for the indexes in each dimension,
	 * the values of the R attribute <code>dimnames</code>, are accessible by {@link #getNames(int)}.
	 * 
	 * The returned character data has the same length as the dimension data {@link #getDim()}.
	 * If the R element does not have names, the names are invalid, or names are disabled, the
	 * method returns <code>null</code>.
	 * 
	 * @return a charater data store with the names of the dimensions or <code>null</code>
	 * 
	 * @since de.walware.rj.data 0.5
	 */
	@Nullable RCharacterStore getDimNames();
	
	/**
	 * Returns the names for the indexes in the given dimension of the array. This corresponds to
	 * the values of the R attribute <code>dimnames</code> respectively of the R function
	 * <code>dimnames(object)</code>. The names for the dimensions itself are accessible by
	 * {@link #getDimNames()}.
	 * 
	 * @param dim the dimension index
	 * @return a data store with the names of the indexes in the given dimensions or <code>null</code>
	 * @throws IndexOutOfBoundsException if dim &lt; 0 or dim &ge; getDim().getLength()
	 * 
	 * @since de.walware.rj.data 0.5
	 */
	@Nullable RStore<?> getNames(int dim);
	
	
	@Override
	TData getData();
	
//	void setDim(int[] dim);
//	void setDimNames(RList list);
//	void insert(int dim, int idx);
//	void remove(int dim, int idx);
	
}