subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/tuple/FlatTuple0.java


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/*******************************************************************************
 * Copyright (c) 2010-2017, Gabor Bergmann, IncQueryLabs Ltd.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-v20.html.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *******************************************************************************/
package tools.refinery.viatra.runtime.matchers.tuple;

/**
 * Flat tuple with statically known arity of 0.
 * 
 * @author Gabor Bergmann
 * @since 1.7
 *
 */
public final class FlatTuple0 extends BaseFlatTuple {
    protected static final FlatTuple0 INSTANCE = new FlatTuple0();

    private FlatTuple0() {
        calcHash();
    }
    
    @Override
    public int getSize() {
        return 0;
    }

    @Override
    public Object get(int index) {
        throw raiseIndexingError(index);
    }

    private static final Object[] NULLARY_ARRAY = new Object[0];
    
    @Override
    public Object[] getElements() {
        return NULLARY_ARRAY;
    }
    
    @Override
    protected boolean internalEquals(ITuple other) {
        return 0 == other.getSize();
    }
}