com.github.dakusui.lisj.special.Loop Maven / Gradle / Ivy

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package com.github.dakusui.lisj.special;

import static com.github.dakusui.lisj.Basic.eval;
import static com.github.dakusui.lisj.Basic.length;

import com.github.dakusui.jcunit.exceptions.JCUnitException;
import com.github.dakusui.jcunit.exceptions.ObjectUnderFrameworkException;
import com.github.dakusui.lisj.BaseForm;
import com.github.dakusui.lisj.Basic;
import com.github.dakusui.lisj.CUT;
import com.github.dakusui.lisj.Context;
import com.github.dakusui.lisj.FormResult;

public class Loop extends BaseForm {
	/**
	 * Serial version UID.
	 */
	private static final long serialVersionUID = 1431934849070993256L;

	@Override
	protected FormResult evaluateLast(Context context,
			Object[] params, FormResult lastResult) {
		return lastResult;
	}

	@Override
	protected FormResult evaluateEach(Context context,
			Object currentParam, FormResult lastResult) throws JCUnitException, CUT {
		currentParam = eval(context, currentParam);
		if (lastResult.nextPosition() == 0) {
			if ((currentParam instanceof Boolean)) {
				if (!(Boolean)currentParam) {
					cut(false);
				}
			} else {
				String msg = String.format("The first parameter of this (%s) object must be a boolean when it is evaluated but '%s'.", this, Basic.tostr(currentParam)); 
				throw new ObjectUnderFrameworkException(msg, null);
			}
		} 
		FormResult ret = lastResult;
		ret.value(currentParam);
		ret.incrementPosition();
		if (ret.nextPosition() >= ret.numPositions()) ret.nextPosition(0);
		return ret;
	}

	/*
	 * The first parameter must be or return a boolean value.
	 * The other parameters can be anything.
	 * 
	 * @see com.github.dakusui.lisj.BaseForm#checkParams(java.lang.Object[])
	 */
	@Override
	protected Object checkParams(Object params) {
		if (length(super.checkParams(params)) < 1) throw new IllegalArgumentException();
		return params;
	}
}