com.freiheit.fuava.simplebatch.result.ComposedResult.java Source code

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Here is the source code for com.freiheit.fuava.simplebatch.result.ComposedResult.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.result;

import com.google.common.collect.Iterables;

public final class ComposedResult<A, B> {

    public static final <A, B> ComposedResult<A, B> of(final Result<A, ?> orig) {
        return new ComposedResult<A, B>(orig);
    }

    private final Result.Builder<A, B> builder;
    private final Object intermediateValue;

    private ComposedResult(final Result<A, ?> orig) {
        builder = Result.<A, B>builder(orig);
        intermediateValue = orig.getOutput();
    }

    public Result<A, B> failed(final String message) {
        return builder.withFailureMessage(message).failed();
    }

    /**
     * If there are no results, fail. If there is one successful result, return
     * success. Add warnings for any values that exceed.
     */
    public Result<A, B> compose(final Iterable<? extends Result<?, B>> results) {
        if (results == null || Iterables.isEmpty(results)) {
            return builder.withFailureMessage(
                    "No intermediate results found. Intermediate input was " + intermediateValue).failed();
        }
        final Result<?, B> firstSuccess = Iterables.find(results, Result::isSuccess);
        for (final Result<?, B> r : results) {
            // add everything that was accumulated in the composed results
            builder.withFailureMessages(r.getFailureMessages()).withWarningMessages(r.getWarningMessages())
                    .withThrowables(r.getThrowables());
        }
        if (firstSuccess == null) {
            return builder.failed();
        }
        return builder.withOutput(firstSuccess.getOutput()).success();
    }
}