com.freiheit.fuava.simplebatch.fetch.PageFetchingSettings.java Source code

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Here is the source code for com.freiheit.fuava.simplebatch.fetch.PageFetchingSettings.java

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/**
 * Copyright 2015 freiheit.com technologies gmbh
 *
 * 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.freiheit.fuava.simplebatch.fetch;

import com.freiheit.fuava.simplebatch.fetch.PageFetcher.PagingInput;
import com.freiheit.fuava.simplebatch.result.Result;
import com.google.common.collect.Iterables;

public interface PageFetchingSettings<T> {
    default boolean hasNext(final int from, final int amount, final Result<PagingInput, T> lastValue) {
        if (lastValue == null || !lastValue.isSuccess()) {
            return false;
        }
        final Object output = lastValue.getOutput();
        if (output instanceof Iterable) {
            return Iterables.size((Iterable) output) >= amount;
        }
        throw new UnsupportedOperationException(
                "cannot calculate paging for " + output + " - please provide your own implementation");

    }
}