org.apache.james.util.Size.java Source code

Introduction

Here is the source code for org.apache.james.util.Size.java

Source

/****************************************************************
 * 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.james.util;

import com.google.common.math.LongMath;

/**
 * This class is an helper for parsing integer input that may contain units.
 */
public class Size {

    public static final String UNKNOWN = "UNKNOWN";
    public static final String UNLIMITED = "UNLIMITED";
    public static final long UNKNOWN_VALUE = Long.MIN_VALUE;
    public static final long UNLIMITED_VALUE = -1;

    /**
     * supported units : B ( 2^0 ), K ( 2^10 ), M ( 2^20 ), G ( 2^30 )
     * See  RFC822.SIZE
     */
    private enum Unit {
        NoUnit, B, K, M, G
    }

    private static final long base = 1024;

    Unit unit;
    Long value;

    private Size(Unit unit, Long value) {
        this.unit = unit;
        this.value = value;
    }

    public static Size parse(String providedLongWithUnitString) throws Exception {
        if (providedLongWithUnitString.equalsIgnoreCase(UNKNOWN)) {
            return new Size(Unit.NoUnit, UNKNOWN_VALUE);
        }
        if (providedLongWithUnitString.equalsIgnoreCase(UNLIMITED)) {
            return new Size(Unit.NoUnit, UNLIMITED_VALUE);
        }
        char lastChar = providedLongWithUnitString.charAt(providedLongWithUnitString.length() - 1);
        Unit unit = getUnit(lastChar);
        String argWithoutUnit = removeLastCharIfNeeded(providedLongWithUnitString, unit);
        return new Size(unit, Long.parseLong(argWithoutUnit));
    }

    public Unit getUnit() {
        return unit;
    }

    public Long getValue() {
        return value;
    }

    public long asBytes() {
        switch (unit) {
        case G:
            return value * LongMath.pow(base, 3);
        case M:
            return value * LongMath.pow(base, 2);
        case K:
            return value * LongMath.pow(base, 1);
        default:
            return value;
        }
    }

    private static String removeLastCharIfNeeded(String providedLongWithUnitString, Unit unit) {
        if (unit != Unit.NoUnit) {
            return providedLongWithUnitString.substring(0, providedLongWithUnitString.length() - 1);
        } else {
            return providedLongWithUnitString;
        }
    }

    private static Unit getUnit(char lastChar) throws Exception {
        switch (lastChar) {
        case 'K':
        case 'k':
            return Unit.K;
        case 'M':
        case 'm':
            return Unit.M;
        case 'G':
        case 'g':
            return Unit.G;
        case 'b':
        case 'B':
            return Unit.B;
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        case '0':
            return Unit.NoUnit;
        default:
            throw new Exception("No unit corresponding to char : " + lastChar);
        }
    }

}