ReservedKeyword.java

/*
 * Copyright 2017 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.springframework.cassandra.core;

import java.util.HashSet;
import java.util.Set;

import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * CQL keywords.
 *
 * @see <a href=
 *      "http://cassandra.apache.org/doc/cql3/CQL.html#appendixA">http://cassandra.apache.org/doc/cql3/CQL.html#appendixA</a>
 * @author Matthew T. Adams
 * @author Mark Paluch
 */
public enum ReservedKeyword {

	ADD, ALTER, AND, ANY, APPLY, ASC, AUTHORIZE, //

	BATCH, BEGIN, BY, COLUMNFAMILY, CREATE, DELETE, DESC, DROP, EACH_QUORUM, //

	FROM, GRANT, IN, INDEX, INSERT, INTO, KEYSPACE, //

	LIMIT, LOCAL_ONE, LOCAL_QUORUM, MODIFY, NORECURSIVE, //

	OF, ON, ONE, ORDER, PRIMARY, QUORUM, REVOKE, SCHEMA, SELECT, SET, //

	TABLE, THREE, TOKEN, TRUNCATE, TWO, UPDATE, USE, USING, WHERE, WITH;

	private static final Set<String> RESERVED;

	static {
		RESERVED = new HashSet<>();
		for (ReservedKeyword keyword : ReservedKeyword.values()) {
			RESERVED.add(keyword.name());
		}
	}

	/**
	 * @see ReservedKeyword#isReserved(String)
	 */
	public static boolean isReserved(CharSequence candidate) {

		Assert.notNull(candidate, "CharSequence must not be null");

		return isReserved(candidate.toString());
	}

	/**
	 * Returns whether the given string is a CQL reserved keyword. This comparison is done regardless of case.
	 *
	 * @param candidate candidate keyword.
	 */
	public static boolean isReserved(String candidate) {

		if (!StringUtils.hasText(candidate)) {
			return false;
		}

		return RESERVED.contains(candidate.toUpperCase());
	}
}