Merge branch 'develop' into features/JAL-1705_ensembl

[jalview.git] / src / jalview / util / HttpUtils.java

diff --git a/src/jalview/util/HttpUtils.java b/src/jalview/util/HttpUtils.java
new file mode 100644 (file)
index 0000000..991a20a
--- /dev/null
+++ b/src/jalview/util/HttpUtils.java
@@ -0,0 +1,67 @@
+/*******************************************************************************
+ * Jalview - A Sequence Alignment Editor and Viewer ($$Version-Rel$$)
+ * Copyright (C) $$Year-Rel$$ The Jalview Authors
+ * 
+ * This file is part of Jalview.
+ * 
+ * Jalview is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License 
+ * as published by the Free Software Foundation, either version 3
+ * of the License, or (at your option) any later version.
+ *  
+ * Jalview is distributed in the hope that it will be useful, but 
+ * WITHOUT ANY WARRANTY; without even the implied warranty 
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
+ * PURPOSE.  See the GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
+ * The Jalview Authors are detailed in the 'AUTHORS' file.
+ ******************************************************************************/
+package jalview.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+
+public class HttpUtils
+{
+
+  /**
+   * Returns true if it is possible to open an input stream at the given URL,
+   * else false. The input stream is closed.
+   * 
+   * @param url
+   * @return
+   */
+  public static boolean isValidUrl(String url)
+  {
+    InputStream is = null;
+    try
+    {
+      is = new URL(url).openStream();
+      if (is != null)
+      {
+        return true;
+      }
+    } catch (IOException x)
+    {
+      // MalformedURLException, FileNotFoundException
+      return false;
+    } finally
+    {
+      if (is != null)
+      {
+        try
+        {
+          is.close();
+        } catch (IOException e)
+        {
+          // ignore
+        }
+      }
+    }
+    return false;
+  }
+
+}