geopt.java

google gdata API 很好用的API

/* Copyright (c) 2006 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.extensions;

import com.google.gdata.util.common.xml.XmlWriter;
import com.google.gdata.data.DateTime;
import com.google.gdata.data.Extension;
import com.google.gdata.data.ExtensionDescription;
import com.google.gdata.data.ExtensionPoint;
import com.google.gdata.data.ExtensionProfile;
import com.google.gdata.util.Namespaces;
import com.google.gdata.util.ParseException;
import com.google.gdata.util.XmlParser;

import org.xml.sax.Attributes;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;


/**
 * GData schema extension describing a geographic location.
 *
 * 
 */
public class GeoPt extends ExtensionPoint implements Extension {


  /** Label. */
  protected String label;
  public String getLabel() { return label; }
  public void setLabel(String v) { label = v; }


  /** Latitude. */
  protected Float lat;
  public Float getLat() { return lat; }
  public void setLat(Float v) { lat = v; }


  /** Longitude. */
  protected Float lon;
  public Float getLon() { return lon; }
  public void setLon(Float v) { lon = v; }


  /** Elevation. */
  protected Float elev;
  public Float getElev() { return elev; }
  public void setElev(Float v) { elev = v; }


  /** Time. */
  protected DateTime time;
  public DateTime getTime() { return time; }
  public void setTime(DateTime v) { time = v; }


  /**
   * Returns the suggested extension description with configurable
   * repeatability.
   */
  public static ExtensionDescription getDefaultDescription(boolean repeatable) {
    ExtensionDescription desc = new ExtensionDescription();
    desc.setExtensionClass(GeoPt.class);
    desc.setNamespace(Namespaces.gNs);
    desc.setLocalName("geoPt");
    desc.setRepeatable(repeatable);
    return desc;
  }

  /** Returns the suggested extension description and is repeatable. */
  public static ExtensionDescription getDefaultDescription() {
    return getDefaultDescription(true);
  }

  public void generate(XmlWriter w, ExtensionProfile extProfile)
      throws IOException {

    ArrayList<XmlWriter.Attribute> attrs = new ArrayList<XmlWriter.Attribute>();

    if (label != null) {
      attrs.add(new XmlWriter.Attribute("label", label));
    }

    if (lat != null) {
      attrs.add(new XmlWriter.Attribute("lat", lat.toString()));
    }

    if (lon != null) {
      attrs.add(new XmlWriter.Attribute("lon", lon.toString()));
    }

    if (elev != null) {
      attrs.add(new XmlWriter.Attribute("elev", elev.toString()));
    }

    if (time != null) {
      attrs.add(new XmlWriter.Attribute("time", time.toString()));
    }

    generateStartElement(w, Namespaces.gNs, "geoPt", attrs, null);

    // Invoke ExtensionPoint.
    generateExtensions(w, extProfile);

    w.endElement(Namespaces.gNs, "geoPt");
  }


  public XmlParser.ElementHandler getHandler(ExtensionProfile extProfile,
                                             String namespace,
                                             String localName,
                                             Attributes attrs)
      throws ParseException, IOException {

    return new Handler(extProfile);
  }


  /** <g:geoPt> parser. */
  private class Handler extends ExtensionPoint.ExtensionHandler {


    public Handler(ExtensionProfile extProfile)
        throws ParseException, IOException {

      super(extProfile, GeoPt.class);
    }


    public void processAttribute(String namespace,
                                 String localName,
                                 String value)
        throws ParseException {

      if (namespace.equals("")) {

        if (localName.equals("label")) {

          label = value;

        } else if (localName.equals("lat")) {

          try {
            lat = Float.valueOf(value);
          } catch (NumberFormatException e) {
            throw new ParseException("Invalid geoPt/@lat.", e);
          }

        } else if (localName.equals("lon")) {

          try {
            lon = Float.valueOf(value);
          } catch (NumberFormatException e) {
            throw new ParseException("Invalid geoPt/@lon.", e);
          }

        } else if (localName.equals("elev")) {

          try {
            elev = Float.valueOf(value);
          } catch (NumberFormatException e) {
            throw new ParseException("Invalid geoPt/@elev.", e);
          }

        } else if (localName.equals("time")) {

          try {
            time = DateTime.parseDateTime(value);
          } catch (NumberFormatException e) {
            throw new ParseException("Date/time value expected.");
          }
        }
      }
    }


    public void processEndElement() throws ParseException {

      if (lat == null) {
        throw new ParseException("g:geoPt/@lat is required.");
      }

      if (lon == null) {
        throw new ParseException("g:geoPt/@lon is required.");
      }

      super.processEndElement();
    }
  }
}