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A shape-based JSON modelling framework.
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/*
 * Copyright © 2013-2022 Metreeca srl
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.metreeca.json.shapes;

import com.metreeca.json.Shape;
import com.metreeca.json.Values;

import static com.metreeca.json.shapes.And.and;
import static com.metreeca.json.shapes.Or.or;


/**
 * Conditional logical constraint.
 *
 * States that the focus set is consistent either with a {@linkplain #pass() positive} shape, if consistent also
 * with a {@linkplain #test() test} shape, or with a {@linkplain #fail() negative} shape, otherwise.
 */
public final class When extends Shape {

	public static Shape when(final Shape test, final Shape pass) {

		if ( test == null ) {
			throw new NullPointerException("null test shape");
		}

		if ( pass == null ) {
			throw new NullPointerException("null pass shape");
		}

		return when(test, pass, and());
	}

	public static Shape when(final Shape test, final Shape pass, final Shape fail) {

		if ( test == null ) {
			throw new NullPointerException("null test shape");
		}

		if ( pass == null ) {
			throw new NullPointerException("null pass shape");
		}

		if ( fail == null ) {
			throw new NullPointerException("null fail shape");
		}

		return test.equals(and()) ? pass
				: test.equals(or()) ? fail
				: pass.equals(fail) ? pass
				: new When(test, pass, fail);
	}


	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

	private final Shape test;
	private final Shape pass;
	private final Shape fail;


	private When(final Shape test, final Shape pass, final Shape fail) {
		this.test=test;
		this.pass=pass;
		this.fail=fail;
	}


	public Shape test() {
		return test;
	}

	public Shape pass() {
		return pass;
	}

	public Shape fail() {
		return fail;
	}


	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

	@Override public  V map(final Probe probe) {

		if ( probe == null ) {
			throw new NullPointerException("null probe");
		}

		return probe.probe(this);
	}


	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

	@Override public boolean equals(final Object object) {
		return this == object || object instanceof When
				&& test.equals(((When)object).test)
				&& pass.equals(((When)object).pass)
				&& fail.equals(((When)object).fail);
	}

	@Override public int hashCode() {
		return test.hashCode()^pass.hashCode()^fail.hashCode();
	}

	@Override public String toString() {
		return "when(\n\t"
				+Values.indent(test.toString())+",\n\t"
				+Values.indent(pass.toString())
				+(fail.equals(and()) ? "" : ",\n\t"+Values.indent(fail.toString()))
				+"\n)";
	}

}