/*
 * Copyright (C) 2014 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.core.configuration;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import lombok.core.configuration.ConfigurationSource.ListModification;
import lombok.core.configuration.ConfigurationSource.Result;

public class BubblingConfigurationResolver implements ConfigurationResolver {
	
	private final Iterable<ConfigurationSource> sources;
	
	public BubblingConfigurationResolver(Iterable<ConfigurationSource> sources) {
		this.sources = sources;
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public <T> T resolve(ConfigurationKey<T> key) {
		boolean isList = key.getType().isList();
		List<ListModification> listModifications = null;
		for (ConfigurationSource source : sources) {
			Result result = source.resolve(key);
			if (result == null) continue;
			if (isList) {
				if (listModifications == null) {
					listModifications = new ArrayList<ListModification>((List<ListModification>)result.getValue());
				} else {
					listModifications.addAll(0, (List<ListModification>)result.getValue());
				}
			}
			if (result.isAuthoritative()) {
				if (isList) {
					break;
				}
				return (T) result.getValue();
			}
		}
		if (!isList) {
			return null;
		}
		if (listModifications == null) {
			return (T) Collections.emptyList();
		}
		List<Object> listValues = new ArrayList<Object>();
		for (ListModification modification : listModifications) {
			listValues.remove(modification.getValue());
			if (modification.isAdded()) {
				listValues.add(modification.getValue());
			}
		}
		return (T) listValues;
	}
}

/*
 * Copyright (C) 2014 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.core.configuration;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import lombok.core.configuration.ConfigurationSource.ListModification;
import lombok.core.configuration.ConfigurationSource.Result;

public class BubblingConfigurationResolver implements ConfigurationResolver {
	
	private final Iterable<ConfigurationSource> sources;
	
	public BubblingConfigurationResolver(Iterable<ConfigurationSource> sources) {
		this.sources = sources;
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public <T> T resolve(ConfigurationKey<T> key) {
		boolean isList = key.getType().isList();
		List<List<ListModification>> listModificationsList = null;
		for (ConfigurationSource source : sources) {
			Result result = source.resolve(key);
			if (result == null) continue;
			if (isList) {
				if (listModificationsList == null) {
					listModificationsList = new ArrayList<List<ListModification>>();
				}
				listModificationsList.add((List<ListModification>)result.getValue());
			}
			if (result.isAuthoritative()) {
				if (isList) {
					break;
				}
				return (T) result.getValue();
			}
		}
		if (!isList) {
			return null;
		}
		if (listModificationsList == null) {
			return (T) Collections.emptyList();
		}
		List<Object> listValues = new ArrayList<Object>();
		Collections.reverse(listModificationsList);
		for (List<ListModification> listModifications : listModificationsList) {
			for (ListModification modification : listModifications) {
				listValues.remove(modification.getValue());
				if (modification.isAdded()) {
					listValues.add(modification.getValue());
				}
			}
		}
		return (T) listValues;
	}
}

Copy less lists during resolving