com.lithium.flow.config.parsers.SubtractConfigParser Maven / Gradle / Ivy

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/*
 * Copyright 2015 Lithium Technologies, Inc.
 *
 * 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.lithium.flow.config.parsers;

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

import com.lithium.flow.config.ConfigBuilder;
import com.lithium.flow.config.ConfigParser;

import javax.annotation.Nonnull;

import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;

/**
 * @author Matt Ayres
 */
public class SubtractConfigParser implements ConfigParser {
	@Override
	public boolean parseLine(@Nonnull String line, @Nonnull ConfigBuilder builder) {
		checkNotNull(line);
		checkNotNull(builder);

		int index = line.indexOf("-=");
		if (index > -1 && index < line.indexOf("=")) {
			String key = line.substring(0, index).trim();
			final String value = line.substring(index + 2).trim();
			String oldValue = builder.getString(key);
			if (oldValue != null) {
				builder.setString(key, Joiner.on(" ").join(Iterables.filter(Splitter.on(" ").split(oldValue),
						input -> !value.equals(input))));
				return true;
			}
		}
		return false;
	}
}