org.apache.druid.common.guava.GuavaUtils.java Source code

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Here is the source code for org.apache.druid.common.guava.GuavaUtils.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.druid.common.guava;

import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.primitives.Longs;

import javax.annotation.Nullable;

/**
 */
public class GuavaUtils {

    /**
     * To fix semantic difference of Longs.tryParse() from Long.parseLong (Longs.tryParse() returns null for '+' started value)
     */
    @Nullable
    public static Long tryParseLong(@Nullable String string) {
        return Strings.isNullOrEmpty(string) ? null
                : Longs.tryParse(string.charAt(0) == '+' ? string.substring(1) : string);
    }

    /**
     * Like Guava's Enums.getIfPresent, with some differences.
     * <ul>
     * <li>Returns nullable rather than Optional</li>
     * <li>Does not require Guava 12</li>
     * </ul>
     */
    @Nullable
    public static <T extends Enum<T>> T getEnumIfPresent(final Class<T> enumClass, final String value) {
        Preconditions.checkNotNull(enumClass, "enumClass");
        Preconditions.checkNotNull(value, "value");

        for (T enumValue : enumClass.getEnumConstants()) {
            if (enumValue.name().equals(value)) {
                return enumValue;
            }
        }

        return null;
    }
}