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Java example source code file (PreciseDurationField.java)

This example Java source code file (PreciseDurationField.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

basedurationfield, precisedurationfield

The PreciseDurationField.java Java example source code

/*
 *  Copyright 2001-2005 Stephen Colebourne
 *
 *  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.joda.time.field;

import org.joda.time.DurationFieldType;

/**
 * Duration field class representing a field with a fixed unit length.
 * <p>
 * PreciseDurationField is thread-safe and immutable.
 * 
 * @author Stephen Colebourne
 * @author Brian S O'Neill
 * @since 1.0
 */
public class PreciseDurationField extends BaseDurationField {
    
    private static final long serialVersionUID = -8346152187724495365L;

    /** The size of the unit */
    private final long iUnitMillis;

    /**
     * Constructor.
     * 
     * @param type  the field type
     * @param unitMillis  the unit milliseconds
     */    
    public PreciseDurationField(DurationFieldType type, long unitMillis) {
        super(type);
        iUnitMillis = unitMillis;
    }
    
    //------------------------------------------------------------------------
    /**
     * This field is precise.
     * 
     * @return true always
     */
    public final boolean isPrecise() {
        return true;
    }
    
    /**
     * Returns the amount of milliseconds per unit value of this field.
     *
     * @return the unit size of this field, in milliseconds
     */
    public final long getUnitMillis() {
        return iUnitMillis;
    }

    //------------------------------------------------------------------------
    /**
     * Get the value of this field from the milliseconds.
     * 
     * @param duration  the milliseconds to query, which may be negative
     * @param instant  ignored
     * @return the value of the field, in the units of the field, which may be
     * negative
     */
    public long getValueAsLong(long duration, long instant) {
        return duration / iUnitMillis;  // safe
    }

    /**
     * Get the millisecond duration of this field from its value.
     * 
     * @param value  the value of the field, which may be negative
     * @param instant  ignored
     * @return the milliseconds that the field represents, which may be
     * negative
     */
    public long getMillis(int value, long instant) {
        return value * iUnitMillis;  // safe
    }

    /**
     * Get the millisecond duration of this field from its value.
     * 
     * @param value  the value of the field, which may be negative
     * @param instant  ignored
     * @return the milliseconds that the field represents, which may be
     * negative
     */
    public long getMillis(long value, long instant) {
        return FieldUtils.safeMultiply(value, iUnitMillis);
    }

    public long add(long instant, int value) {
        long addition = value * iUnitMillis;  // safe
        return FieldUtils.safeAdd(instant, addition);
    }

    public long add(long instant, long value) {
        long addition = FieldUtils.safeMultiply(value, iUnitMillis);
        return FieldUtils.safeAdd(instant, addition);
    }

    public long getDifferenceAsLong(long minuendInstant, long subtrahendInstant) {
        long difference = FieldUtils.safeSubtract(minuendInstant, subtrahendInstant);
        return difference / iUnitMillis;
    }

    //-----------------------------------------------------------------------
    /**
     * Compares this duration field to another.
     * Two fields are equal if of the same type and duration.
     * 
     * @param obj  the object to compare to
     * @return if equal
     */
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        } else if (obj instanceof PreciseDurationField) {
            PreciseDurationField other = (PreciseDurationField) obj;
            return (getType() == other.getType()) && (iUnitMillis == other.iUnitMillis);
        }
        return false;
    }

    /**
     * Gets a hash code for this instance.
     * 
     * @return a suitable hashcode
     */
    public int hashCode() {
        long millis = iUnitMillis;
        int hash = (int) (millis ^ (millis >>> 32));
        hash += getType().hashCode();
        return hash;
    }

}

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