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Java example source code file (PreciseDateTimeField.java)

This example Java source code file (PreciseDateTimeField.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

durationfield, illegalargumentexception, precisedatetimefield, precisedurationdatetimefield, range, suppresswarnings, the

The PreciseDateTimeField.java Java example source code

/*
 *  Copyright 2001-2013 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.DateTimeFieldType;
import org.joda.time.DurationField;

/**
 * Precise datetime field, composed of two precise duration fields.
 * <p>
 * This DateTimeField is useful for defining DateTimeFields that are composed
 * of precise durations, like time of day fields. If either duration field is
 * imprecise, then an {@link ImpreciseDateTimeField} may be used instead.
 * <p>
 * PreciseDateTimeField is thread-safe and immutable.
 *
 * @author Brian S O'Neill
 * @author Stephen Colebourne
 * @since 1.0
 * @see ImpreciseDateTimeField
 */
public class PreciseDateTimeField extends PreciseDurationDateTimeField {

    @SuppressWarnings("unused")
    private static final long serialVersionUID = -5586801265774496376L;

    /** The maximum range in the correct units */
    private final int iRange;

    private final DurationField iRangeField;

    /**
     * Constructor.
     * 
     * @param type  the field type this field uses
     * @param unit  precise unit duration, like "seconds()".
     * @param range precise range duration, preferably a multiple of the unit,
     * like "minutes()".
     * @throws IllegalArgumentException if either duration field is imprecise
     * @throws IllegalArgumentException if unit milliseconds is less than one
     * or effective value range is less than two.
     */
    public PreciseDateTimeField(DateTimeFieldType type,
                                DurationField unit, DurationField range) {
        super(type, unit);

        if (!range.isPrecise()) {
            throw new IllegalArgumentException("Range duration field must be precise");
        }

        long rangeMillis = range.getUnitMillis();
        iRange = (int)(rangeMillis / getUnitMillis());
        if (iRange < 2) {
            throw new IllegalArgumentException("The effective range must be at least 2");
        }

        iRangeField = range;
    }

    /**
     * Get the amount of fractional units from the specified time instant.
     * 
     * @param instant  the milliseconds from 1970-01-01T00:00:00Z to query
     * @return the amount of fractional units extracted from the input.
     */
    public int get(long instant) {
        if (instant >= 0) {
            return (int) ((instant / getUnitMillis()) % iRange);
        } else {
            return iRange - 1 + (int) (((instant + 1) / getUnitMillis()) % iRange);
        }
    }

    /**
     * Add to the component of the specified time instant, wrapping around
     * within that component if necessary.
     * 
     * @param instant  the milliseconds from 1970-01-01T00:00:00Z to add to
     * @param amount  the amount of units to add (can be negative).
     * @return the updated time instant.
     */
    public long addWrapField(long instant, int amount) {
        int thisValue = get(instant);
        int wrappedValue = FieldUtils.getWrappedValue
            (thisValue, amount, getMinimumValue(), getMaximumValue());
        // copy code from set() to avoid repeat call to get()
        return instant + (wrappedValue - thisValue) * getUnitMillis();
    }

    /**
     * Set the specified amount of units to the specified time instant.
     * 
     * @param instant  the milliseconds from 1970-01-01T00:00:00Z to set in
     * @param value  value of units to set.
     * @return the updated time instant.
     * @throws IllegalArgumentException if value is too large or too small.
     */
    public long set(long instant, int value) {
        FieldUtils.verifyValueBounds(this, value, getMinimumValue(), getMaximumValue());
        return instant + (value - get(instant)) * iUnitMillis;
    }

    /**
     * Returns the range duration of this field. For example, if this field
     * represents "minute of hour", then the range duration field is an hours.
     *
     * @return the range duration of this field, or null if field has no range
     */
    public DurationField getRangeDurationField() {
        return iRangeField;
    }

    /**
     * Get the maximum value for the field.
     * 
     * @return the maximum value
     */
    public int getMaximumValue() {
        return iRange - 1;
    }
    
    /**
     * Returns the range of the field in the field's units.
     * <p>
     * For example, 60 for seconds per minute. The field is allowed values
     * from 0 to range - 1.
     * 
     * @return unit range
     */
    public int getRange() {
        return iRange;
    }

}

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