Java tutorial
/** * Copyright (c) Codice Foundation * <p> * This is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser * General Public License as published by the Free Software Foundation, either version 3 of the * License, or any later version. * <p> * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. A copy of the GNU Lesser General Public License * is distributed along with this program and can be found at * <http://www.gnu.org/licenses/lgpl.html>. */ package ddf.catalog.validation.impl; import java.util.Collections; import java.util.HashSet; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import org.apache.commons.collections.CollectionUtils; import com.google.common.base.Preconditions; import ddf.catalog.validation.AttributeValidator; import ddf.catalog.validation.AttributeValidatorRegistry; public class AttributeValidatorRegistryImpl implements AttributeValidatorRegistry { private final Map<String, Set<AttributeValidator>> attributeValidatorMap = new ConcurrentHashMap<>(); @Override public void registerValidators(final String attributeName, final Set<? extends AttributeValidator> validators) { Preconditions.checkArgument(attributeName != null, "The attribute name cannot be null."); Preconditions.checkArgument(CollectionUtils.isNotEmpty(validators), "Must register at least one validator."); attributeValidatorMap.compute(attributeName, (name, registeredValidators) -> { if (registeredValidators == null) { return new HashSet<>(validators); } else { registeredValidators.addAll(validators); return registeredValidators; } }); } @Override public void deregisterValidators(final String attributeName) { Preconditions.checkArgument(attributeName != null, "The attribute name cannot be null."); attributeValidatorMap.remove(attributeName); } @Override public Set<AttributeValidator> getValidators(final String attributeName) { Preconditions.checkArgument(attributeName != null, "The attribute name cannot be null."); return Collections .unmodifiableSet(attributeValidatorMap.getOrDefault(attributeName, Collections.emptySet())); } }