/* Copyright (c) 2008 Google Inc.
*
* 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 com.google.gdata.data.geo;
import com.google.gdata.data.ExtensionDescription;
import com.google.gdata.data.ValueConstruct;
import java.text.NumberFormat;
/**
* Extension for a W3C geo:long element. It contains the getter/setter for
* specifying the longitude of a geo-coordinate. The coordinate is contained
* within the long element as: {@literal <geo:long>coordinate</geo:long>}.
* Note that the longitude element does not need to be a child of the geo:Point
* element. Please see the W3C document
* <a href="http://www.w3.org/2003/01/geo">http://www.w3.org/2003/01/geo</a> for
* more information.
*
* @see com.google.gdata.data.geo.impl.W3CPoint
*
*/
@ExtensionDescription.Default(
nsAlias=Namespaces.W3C_GEO_ALIAS,
nsUri=Namespaces.W3C_GEO,
localName="long")
public class GeoLong extends ValueConstruct {
/**
* The maximmum acceptable value of a longitude coordinate in degrees.
*/
public static final double MAX_LONG = 180.0d;
/**
* The minimum acceptable value of a longitude coordinate in degrees.
*/
public static final double MIN_LONG = -180.0d;
/**
* This denotes the number of significant digits after the decimal point
* for a coordinate when represented by a string.
*/
public static final int COORDINATE_PRECISION = 6;
private static final NumberFormat NUM_FORMAT = NumberFormat.getInstance();
static {
NUM_FORMAT.setMaximumFractionDigits(COORDINATE_PRECISION);
NUM_FORMAT.setMinimumFractionDigits(COORDINATE_PRECISION);
}
private Double lon = null;
/**
* Creates an instance of the GeoLong extension without a
* longitude value set.
*/
public GeoLong() {
this(null);
}
/**
* Creates an immutable instance of GeoLong extension with the coordinate
* set to the value passed in.
*
* @param lon The longitude coordinate reprensented by this element.
* @throws IllegalArgumentException if the longitude is not between
* -180 and 180 degrees.
*/
public GeoLong(Double lon) throws IllegalArgumentException {
super(Namespaces.W3C_GEO_NAMESPACE, "long", null, null);
setRequired(true);
if (lon != null) {
setLongitude(lon);
setImmutable(true);
}
}
/**
* Returns the actual double coordinate for longitude. Note this value
* is not rounded unlike the value returned by getValue().
*
* @return the longitude represented by this element.
*/
public Double getLongitude() {
return lon;
}
/**
* Sets the longitude represented by this element.
*
* @param longitude the longitude of this element.
*/
public void setLongitude(Double longitude) {
// Note longitude might be null.
lon = longitude;
String value = null;
if (longitude != null) {
if (longitude.compareTo(MIN_LONG) < 0 ||
longitude.compareTo(MAX_LONG) > 0) {
throw new IllegalArgumentException("Longitude must be between " +
"-180 and 180 degrees.");
}
// Format the string so that it has a consistent number of digits
// after the decimal place.
value = NUM_FORMAT.format(longitude);
}
super.setValue(value);
}
/**
* Overrides base implementation by validating that the string represents
* a longitude coordinate between -180 and 180 degrees. Also formats the
* the string so that it has a consistent number of significant digits
* after the decimal point.
*/
@Override
public void setValue(String value) {
Double d = null;
if (value != null) {
// First ensure that the string is actually a double.
try {
d = Double.parseDouble(value);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("'value' must be a double.");
}
}
setLongitude(d);
}
}