uk.gov.gchq.gaffer.data.graph.function.walk.ExtractWalkVertex Maven / Gradle / Ivy

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There is a newer version: 2.3.1

/*
 * Copyright 2017-2020 Crown Copyright
 *
 * 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 uk.gov.gchq.gaffer.data.graph.function.walk;

import uk.gov.gchq.gaffer.data.graph.Walk;
import uk.gov.gchq.koryphe.Since;
import uk.gov.gchq.koryphe.Summary;
import uk.gov.gchq.koryphe.function.KorypheFunction;

/**
 * An {@code ExtractWalkVertex} is a utility {@link KorypheFunction},
 * for simplifying the extraction of the starting Vertex from a {@link Walk} object.
 */
@Since("1.3.0")
@Summary("Extracts the source vertex from a Walk")
public class ExtractWalkVertex extends KorypheFunction {
    @Override
    public Object apply(final Walk walk) {
        if (null == walk) {
            throw new IllegalArgumentException("Walk cannot be null");
        }
        return walk.getSourceVertex();
    }
}