CASC-64

capture and send redirect

cas-client-core/src/main/java/org/jasig/cas/client/util/ErrorRedirectFilter.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2007 The JA-SIG Collaborative. All rights reserved. See license
+ * distributed with this file and available online at
+ * http://www.ja-sig.org/products/cas/overview/license/index.html
+ */
+package org.jasig.cas.client.util;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Filters that redirects to the supplied url based on an exception.  Exceptions and the urls are configured via
+ * init filter name/param values.
+ * <p>
+ * If there is an exact match the filter uses that value.  If there's a non-exact match (i.e. inheritance), then the filter
+ * uses the last value that matched.
+ *  
+ * @author Scott Battaglia
+ * @version $Revision$ $Date$
+ * @since 3.1.4
+ *
+ */
+public final class ErrorRedirectFilter implements Filter {
+
+	private final Log log = LogFactory.getLog(getClass());
+	
+	private final List errors = new ArrayList();
+	
+	public void destroy() {
+		// nothing to do here
+	}
+
+	public void doFilter(final ServletRequest request, final ServletResponse response,
+			final FilterChain filterChain) throws IOException, ServletException {
+		try {
+			filterChain.doFilter(request, response);
+		} catch (final ServletException e) {
+			final Throwable t = e.getCause();
+			ErrorHolder currentMatch = null;
+			for (final Iterator iter = this.errors.iterator(); iter.hasNext();) {
+				final ErrorHolder errorHolder = (ErrorHolder) iter.next();
+				if (errorHolder.exactMatch(t)) {
+					currentMatch = errorHolder;
+					break;
+				} else if (errorHolder.inheritanceMatch(t)) {
+					currentMatch = errorHolder;
+				}
+			}
+			
+			if (currentMatch != null) {
+				final HttpServletResponse httpResponse = (HttpServletResponse) response;
+				httpResponse.sendRedirect(currentMatch.getUrl());
+				return;	
+			}
+			throw e;
+		}
+	}
+
+	public void init(final FilterConfig filterConfig) throws ServletException {
+		final Enumeration enumeration = filterConfig.getInitParameterNames();
+		
+		while (enumeration.hasMoreElements()) {
+			final String className = (String) enumeration.nextElement();
+			try {
+				this.errors.add(new ErrorHolder(className, filterConfig.getInitParameter(className)));
+			} catch (final ClassNotFoundException e) {
+				log.warn("Class [" + className + "] cannot be found in ClassLoader.  Ignoring.");
+			}
+		}
+	}
+	
+	protected final class ErrorHolder {
+		
+		private Class className;
+		
+		private String url;
+		
+		protected ErrorHolder(final String className, final String url) throws ClassNotFoundException {
+			this.className = Class.forName(className);
+			this.url = url;
+		}
+		
+		public boolean exactMatch(final Throwable e) {
+			return this.className.equals(e.getClass());
+		}
+		
+		public boolean inheritanceMatch(final Throwable e) {
+			return className.isAssignableFrom(e.getClass());
+		}
+		
+		public String getUrl() {
+			return this.url;
+		}
+	}
+}