storm-core/src/jvm/org/apache/storm/utils/ObjectReader.java

/*
 * 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.storm.utils;

public class ObjectReader {

    public static String getString(Object o) {
        if (null == o) {
            throw new IllegalArgumentException("Don't know how to convert null to String");
        }
        return o.toString();
    }

    public static Integer getInt(Object o) {
        Integer result = getInt(o, null);
        if (null == result) {
            throw new IllegalArgumentException("Don't know how to convert null to int");
        }
        return result;
    }

    public static Integer getInt(Object o, Integer defaultValue) {
        if (null == o) {
            return defaultValue;
        }

        if (o instanceof Integer ||
                o instanceof Short ||
                o instanceof Byte) {
            return ((Number) o).intValue();
        } else if (o instanceof Long) {
            final long l = (Long) o;
            if (l <= Integer.MAX_VALUE && l >= Integer.MIN_VALUE) {
                return (int) l;
            }
        } else if (o instanceof String) {
            return Integer.parseInt((String) o);
        }

        throw new IllegalArgumentException("Don't know how to convert " + o + " to int");
    }
}