platform/lang-api/src/com/intellij/facet/frameworks/SettingsConnectionService.java

/*
 * Copyright 2000-2011 JetBrains s.r.o.
 *
 * 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.intellij.facet.frameworks;

import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.util.JDOMUtil;
import com.intellij.openapi.util.io.FileUtil;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.util.containers.ContainerUtil;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;

public abstract class SettingsConnectionService {
  private static final Logger LOG = Logger.getInstance("com.intellij.facet.frameworks.SettingsConnectionService");

  protected static final String SERVICE_URL_ATTR_NAME = "url";

  private static final String myAgentID = "IntelliJ IDEA";

  private Map<String, String> myAttributesMap;

  @NotNull
  protected String[] getAttributeNames() {
       return new String[] {SERVICE_URL_ATTR_NAME};
  }

  private final String mySettingsUrl;
  @Nullable private final String myDefaultServiceUrl;

  protected SettingsConnectionService(@NotNull String settingsUrl, @Nullable String defaultServiceUrl) {
    mySettingsUrl = settingsUrl;
    myDefaultServiceUrl = defaultServiceUrl;
  }

  public String getSettingsUrl() {
    return mySettingsUrl;
  }

  @Nullable
  public String getDefaultServiceUrl() {
    return myDefaultServiceUrl;
  }

  @Nullable
  private Map<String, String> readSettings(String... attributes) {
    Map<String, String> settings = ContainerUtil.newLinkedHashMap();
    try {
      URL url = new URL(getSettingsUrl());
      String text = FileUtil.loadTextAndClose(getStream(url));
      try {
        Document document = JDOMUtil.loadDocument(text);
        Element root = document.getRootElement();
        for (String s : attributes) {
          String attributeValue = root.getAttributeValue(s);
          if (StringUtil.isNotEmpty(attributeValue)) {
            settings.put(s, attributeValue);
          }
        }
      }
      catch (JDOMException e) {
        LOG.error("", e, text);
      }
    }
    catch (MalformedURLException e) {
      LOG.error(e);
    }
    catch (IOException e) {
      // no route to host, unknown host, etc.
    }
    catch (Exception e) {
      LOG.error(e);
    }

    return settings;
  }

  private static InputStream getStream(URL url) throws IOException {
    final URLConnection connection = url.openConnection();
    if (connection instanceof HttpURLConnection) {
      connection.setRequestProperty("User-agent", myAgentID);
    }
    return connection.getInputStream();
  }

  @Nullable
  public String getServiceUrl() {
    final String serviceUrl = getSettingValue(SERVICE_URL_ATTR_NAME);

    return serviceUrl == null ? getDefaultServiceUrl() : serviceUrl;
  }

  @Nullable
  protected String getSettingValue(@NotNull String attributeValue) {
    if (myAttributesMap == null) {
      myAttributesMap = readSettings(getAttributeNames());
    }
    return myAttributesMap != null ? myAttributesMap.get(attributeValue) : null;
  }
}