MandatoryOptionValidator.java

/*
 * Copyright 2014-2016 the original author or authors.
 *
 * 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 org.liquigraph.core.configuration.validators;

import org.liquigraph.core.io.xml.ChangelogLoader;

import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.LinkedList;

import static java.lang.String.format;

public class MandatoryOptionValidator {

    public Collection<String> validate(ChangelogLoader loader, String masterChangelog) {
        Collection<String> errors = new LinkedList<>();
        errors.addAll(validateMasterChangelog(masterChangelog, loader));
        return errors;
    }

    private static Collection<String> validateMasterChangelog(String masterChangelog, ChangelogLoader loader) {
        Collection<String> errors = new LinkedList<>();
        if (masterChangelog == null) {
            errors.add("'masterChangelog' should not be null");
        }
        else {
            try (InputStream stream = loader.load(masterChangelog)) {
                if (stream == null) {
                    errors.add(format("'masterChangelog' points to a non-existing location: %s", masterChangelog));
                }
            } catch (IOException e) {
                errors.add(format("'masterChangelog' read error. Cause: %s", e.getMessage()));
            }
        }
        return errors;
    }

}