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 * Java implementation of the SciJava Ops matching engine.
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package org.scijava.ops.engine.matcher.reduce;

import java.lang.reflect.Type;

import org.scijava.ops.api.OpInfo;
import org.scijava.ops.engine.BaseOpHints;
import org.scijava.common3.Types;
import org.scijava.types.infer.FunctionalInterfaces;

public abstract class AbstractInfoReducer implements InfoReducer {

	@Override
	public boolean canReduce(OpInfo info) {
        var isReducerType = isReducerType(FunctionalInterfaces.findFrom(info
			.opType()));
        var canReduce = info.declaredHints().containsNone(
			BaseOpHints.Reduction.FORBIDDEN);
		return isReducerType && canReduce;
	}

	@Override
	public ReducedOpInfo reduce(OpInfo info, int numReductions) {
        var rawType = FunctionalInterfaces.findFrom(info.opType());
        var originalArity = arityOf(rawType);
        var reducedArity = originalArity - numReductions;
        var reducedRawType = ofArity(reducedArity);
        var inputTypes = info.inputTypes().toArray(Type[]::new);
        var outputType = info.output().type();
        var newTypes = new Type[reducedArity + 1];
		if (reducedArity >= 0) System.arraycopy(inputTypes, 0, newTypes, 0,
			reducedArity);
		newTypes[newTypes.length - 1] = outputType;
		Type reducedOpType = Types.parameterize(reducedRawType, newTypes);
		return new ReducedOpInfo(info, reducedOpType, originalArity - reducedArity);
	}

	protected abstract boolean isReducerType(Class<?> functionalInterface);

	protected abstract int arityOf(Class<?> rawType);

	protected abstract Class<?> ofArity(int reducedArity);
}
