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Common subproject in the Theta model checking framework
There is a newer version: 6.5.2
/*
 *  Copyright 2024 Budapest University of Technology and Economics
 *
 *  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 hu.bme.mit.theta.common;

import java.util.function.Supplier;

import static com.google.common.base.Preconditions.checkNotNull;

public abstract class Try {

    private Try() {
    }

    public static  Try attempt(final Supplier supplier) {
        try {
            final T value = supplier.get();
            return success(value);
        } catch (final Exception exception) {
            return failure(exception);
        }
    }

    public static  Success success(final T value) {
        return new Success<>(value);
    }

    public static  Failure failure(final Exception exception) {
        return new Failure<>(exception);
    }

    public abstract boolean isSuccess();

    public abstract boolean isFailure();

    public abstract Success asSuccess();

    public abstract Failure asFailure();

    public static final class Success extends Try {

        private static final int HASH_SEED = 2851;
        private volatile int hashCode = 0;

        private final T value;

        private Success(final T value) {
            this.value = checkNotNull(value);
        }

        public T getValue() {
            return value;
        }

        @Override
        public boolean isSuccess() {
            return true;
        }

        @Override
        public boolean isFailure() {
            return false;
        }

        @Override
        public Success asSuccess() {
            return this;
        }

        @Override
        public Failure asFailure() {
            throw new ClassCastException();
        }

        @Override
        public final int hashCode() {
            int result = hashCode;
            if (result == 0) {
                result = HASH_SEED;
                result = 31 * result + value.hashCode();
                hashCode = result;
            }
            return hashCode;
        }

        @Override
        public final boolean equals(final Object obj) {
            if (this == obj) {
                return true;
            } else if (obj == null) {
                return false;
            } else if (obj != null && this.getClass() == obj.getClass()) {
                final Success that = (Success) obj;
                return this.value.equals(that.value);
            } else {
                return false;
            }
        }

        @Override
        public String toString() {
            return Utils.lispStringBuilder("Success").add(value).toString();
        }
    }

    public static final class Failure extends Try {

        private static final int HASH_SEED = 4271;
        private volatile int hashCode = 0;

        private final Exception exception;

        private Failure(final Exception exception) {
            this.exception = checkNotNull(exception);
        }

        public Exception getException() {
            return exception;
        }

        public void raise() throws Exception {
            throw exception;
        }

        @Override
        public boolean isSuccess() {
            return false;
        }

        @Override
        public boolean isFailure() {
            return true;
        }

        @Override
        public Success asSuccess() {
            throw new ClassCastException();
        }

        @Override
        public Failure asFailure() {
            return this;
        }

        @Override
        public final int hashCode() {
            int result = hashCode;
            if (result == 0) {
                result = HASH_SEED;
                result = 31 * result + exception.hashCode();
                hashCode = result;
            }
            return hashCode;
        }

        @Override
        public final boolean equals(final Object obj) {
            if (this == obj) {
                return true;
            } else if (obj == null) {
                return false;
            } else if (obj != null && this.getClass() == obj.getClass()) {
                final Failure that = (Failure) obj;
                return this.exception.equals(that.exception);
            } else {
                return false;
            }
        }

        @Override
        public String toString() {
            return Utils.lispStringBuilder("Faliure").add(exception).toString();
        }
    }

}