/*
* 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.goda.time.field;
import java.io.Serializable;
import org.goda.time.DurationField;
import org.goda.time.DurationFieldType;
/**
* BaseDurationField provides the common behaviour for DurationField
* implementations.
* <p>
* This class should generally not be used directly by API users. The
* DurationField class should be used when different kinds of DurationField
* objects are to be referenced.
* <p>
* BaseDurationField is thread-safe and immutable, and its subclasses must
* be as well.
*
* @author Brian S O'Neill
* @see DecoratedDurationField
* @since 1.0
*/
public abstract class BaseDurationField extends DurationField implements Serializable {
/** Serialization lock. */
private static final long serialVersionUID = -2554245107589433218L;
/** A desriptive name for the field. */
private final DurationFieldType iType;
protected BaseDurationField(DurationFieldType type) {
super();
if (type == null) {
throw new IllegalArgumentException("The type must not be null");
}
iType = type;
}
public final DurationFieldType getType() {
return iType;
}
public final String getName() {
return iType.getName();
}
/**
* @return true always
*/
public final boolean isSupported() {
return true;
}
//------------------------------------------------------------------------
/**
* Get the value of this field from the milliseconds, which is approximate
* if this field is imprecise.
*
* @param duration the milliseconds to query, which may be negative
* @return the value of the field, in the units of the field, which may be
* negative
*/
public int getValue(long duration) {
return FieldUtils.safeToInt(getValueAsLong(duration));
}
/**
* Get the value of this field from the milliseconds, which is approximate
* if this field is imprecise.
*
* @param duration the milliseconds to query, which may be negative
* @return the value of the field, in the units of the field, which may be
* negative
*/
public long getValueAsLong(long duration) {
return duration / getUnitMillis();
}
/**
* Get the value of this field from the milliseconds relative to an
* instant.
*
* <p>If the milliseconds is positive, then the instant is treated as a
* "start instant". If negative, the instant is treated as an "end
* instant".
*
* <p>The default implementation returns
* <code>Utils.safeToInt(getAsLong(millisDuration, instant))</code>.
*
* @param duration the milliseconds to query, which may be negative
* @param instant the start instant to calculate relative to
* @return the value of the field, in the units of the field, which may be
* negative
*/
public int getValue(long duration, long instant) {
return FieldUtils.safeToInt(getValueAsLong(duration, instant));
}
/**
* Get the millisecond duration of this field from its value, which is
* approximate if this field is imprecise.
*
* @param value the value of the field, which may be negative
* @return the milliseconds that the field represents, which may be
* negative
*/
public long getMillis(int value) {
return value * getUnitMillis(); // safe
}
/**
* Get the millisecond duration of this field from its value, which is
* approximate if this field is imprecise.
*
* @param value the value of the field, which may be negative
* @return the milliseconds that the field represents, which may be
* negative
*/
public long getMillis(long value) {
return FieldUtils.safeMultiply(value, getUnitMillis());
}
// Calculation API
//------------------------------------------------------------------------
public int getDifference(long minuendInstant, long subtrahendInstant) {
return FieldUtils.safeToInt(getDifferenceAsLong(minuendInstant, subtrahendInstant));
}
//------------------------------------------------------------------------
public int compareTo(Object durationField) {
DurationField otherField = (DurationField) durationField;
long otherMillis = otherField.getUnitMillis();
long thisMillis = getUnitMillis();
// cannot do (thisMillis - otherMillis) as can overflow
if (thisMillis == otherMillis) {
return 0;
}
if (thisMillis < otherMillis) {
return -1;
} else {
return 1;
}
}
/**
* Get a suitable debug string.
*
* @return debug string
*/
public String toString() {
return "DurationField[" + getName() + ']';
}
}