1 files changed, 263 insertions, 0 deletions
diff --git a/utils/src/main/java/at/gv/egiz/slbinding/RedirectEventFilter.java b/utils/src/main/java/at/gv/egiz/slbinding/RedirectEventFilter.java
new file mode 100644
index 00000000..5fe84aae
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+++ b/utils/src/main/java/at/gv/egiz/slbinding/RedirectEventFilter.java
@@ -0,0 +1,263 @@
+/*
+ * Copyright 2008 Federal Chancellery Austria and
+ * Graz University of Technology
+ *
+ * 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.
+ */
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package at.gv.egiz.slbinding;
+
+import java.io.OutputStream;
+import java.util.Set;
+import javax.xml.namespace.NamespaceContext;
+import javax.xml.namespace.QName;
+import javax.xml.stream.EventFilter;
+import javax.xml.stream.XMLEventWriter;
+import javax.xml.stream.XMLOutputFactory;
+import javax.xml.stream.XMLStreamConstants;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.XMLEvent;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/*
+ * TODO: don't set redirect stream from caller (caller does not know whether redirection will be triggered)
+ * rather create on trigger and pass to caller
+ */
+public class RedirectEventFilter implements EventFilter {
+
+  public static final String DEFAULT_ENCODING = "UTF-8";
+  private static Log log = LogFactory.getLog(RedirectEventFilter.class);
+  protected XMLEventWriter redirectWriter = null;
+  protected Set<QName> redirectTriggers = null;
+  private int depth = -1;
+  protected NamespaceContext currentNamespaceContext = null;
+
+  /**
+   * Event redirection is disabled, set a redirect stream to enable.
+   */
+  public RedirectEventFilter() {
+    redirectWriter = null;
+  // redirectTriggers = null;
+  }
+
+  /**
+   *
+   * @param redirectStream
+   *          if null, no events are redirected
+   * @param redirectTriggers
+   *          if null, all events are redirected
+   */
+  public RedirectEventFilter(OutputStream redirectStream, String encoding)
+          throws XMLStreamException { // , List<QName> redirectTriggers
+    if (redirectStream != null) {
+      XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
+      if (encoding == null) {
+        encoding = DEFAULT_ENCODING;
+      }
+      this.redirectWriter = outputFactory.createXMLEventWriter(redirectStream,
+              encoding);
+    }
+  // this.redirectTriggers = redirectTriggers;
+  }
+
+  /**
+   * All startElement events occuring in the redirectTriggers list will trigger
+   * redirection of the entire (sub-)fragment.
+   *
+   * @param event
+   * @return false if an event is redirected
+   */
+  @Override
+  public boolean accept(XMLEvent event) {
+    int eventType = event.getEventType();
+
+    if (eventType == XMLStreamConstants.START_ELEMENT) {
+      //hopefully, this is a copy
+      currentNamespaceContext = event.asStartElement().getNamespaceContext();
+    }
+    if (redirectWriter == null) {
+      return true;
+    }
+    if (eventType == XMLStreamConstants.START_ELEMENT) {
+      if (depth >= 0 || triggersRedirect(event.asStartElement().getName())) {
+        depth++;
+      }
+    } else if (eventType == XMLStreamConstants.END_ELEMENT) {
+      if (depth >= 0 && --depth < 0) {
+        // redirect the end element of the trigger,
+        // but do not redirect the end element of the calling type
+        if (redirectTriggers != null) {
+          redirectEvent(event);
+          return false;
+        }
+      }
+    }
+    if (depth >= 0) { //|| (depth == 0 && redirectTriggers == null)) {
+      redirectEvent(event);
+      return false;
+    }
+    return true; // depth < 0;
+
+//    switch (event.getEventType()) {
+//    case XMLStreamConstants.START_ELEMENT:
+//      StartElement startElt = event.asStartElement();
+//      if (depth >= 0 || triggersRedirect(startElt.getName())) {
+//        depth++;
+//      }
+//      // namespace context changes only on start elements
+//      // (first event might not be startElement, but we don't need CDATA's
+//      // namespace context)
+//      currentNamespaceContext = startElt.getNamespaceContext();
+//      break;
+//    case XMLStreamConstants.END_ELEMENT:
+//      // if depth switches from positive to negative, this is the closing tag of
+//      // the trigger (redirect as well!)
+//      if (depth >= 0 && --depth < 0) {
+//        redirectEvent(event);
+//        return false;
+//      }
+//      break;
+//    }
+//    if (depth >= 0) {
+//      redirectEvent(event);
+//      return false;
+//    }
+//    return true; // depth < 0;
+  }
+
+  /**
+   * @param startElt
+   * @return true if the set of triggers contains startElement
+   * (or no triggers are registered, i.e. everything is redirected)
+   */
+  private boolean triggersRedirect(QName startElement) {
+    if (redirectTriggers != null) {
+      return redirectTriggers.contains(startElement);
+    }
+    return true;
+  }
+
+  private void redirectEvent(XMLEvent event) {
+    try {
+      redirectWriter.add(event);
+    } catch (XMLStreamException ex) {
+      ex.printStackTrace();
+    }
+  }
+
+  /**
+   * Enable/disable redirection of <em>all</em> events from now on.
+   * The redirected events will be UTF-8 encoded and written to the stream.
+   *
+   * @param redirectstream
+   *          if null, redirection is disabled
+   */
+  public void setRedirectStream(OutputStream redirectStream) throws XMLStreamException {
+    setRedirectStream(redirectStream, DEFAULT_ENCODING, null);
+  }
+
+  /**
+   * Enable/disable redirection of <em>all</em> events from now on.
+   *
+   * @param redirectStream if null, redirection is disabled
+   * @param encoding The encoding for the redirect stream
+   * @throws javax.xml.stream.XMLStreamException
+   */
+  public void setRedirectStream(OutputStream redirectStream, String encoding) throws XMLStreamException {
+    setRedirectStream(redirectStream, encoding, null);
+  }
+
+  /**
+   * Enable/disable redirection of all (child) elements contained in redirect triggers.
+   * The redirected events will be UTF-8 encoded and written to the stream.
+   *
+   * @param redirectstream
+   *          if null, redirection is disabled
+   * @param redirectTriggers elements that trigger the redirection
+   */
+  public void setRedirectStream(OutputStream redirectStream, Set<QName> redirectTriggers) throws XMLStreamException {
+    setRedirectStream(redirectStream, DEFAULT_ENCODING, redirectTriggers);
+  }
+
+  /**
+   * Enable/disable redirection of all (child) elements contained in redirect triggers.
+   *
+   * TODO: don't set redirect stream from caller (caller does not know whether redirection will be triggered)
+   * rather create on trigger and pass to caller
+   * @param redirectstream
+   *          if null, redirection is disabled
+   * @param encoding The encoding for the redirect stream
+   * @param redirectTriggers elements that trigger the redirection
+   */
+  public void setRedirectStream(OutputStream redirectStream, String encoding, Set<QName> redirectTriggers) throws XMLStreamException {
+    if (redirectStream != null) {
+      XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
+      if (encoding == null) {
+        encoding = DEFAULT_ENCODING;
+      }
+      redirectWriter = outputFactory.createXMLEventWriter(redirectStream,
+              encoding);
+      if (redirectTriggers == null) {
+        // start redirecting
+        depth = 0;
+      }
+      this.redirectTriggers = redirectTriggers;
+    } else {
+      redirectWriter = null;
+      this.redirectTriggers = null;
+    }
+  }
+
+  /**
+   * Enable/disable redirection of fragments (defined by elements in
+   * redirectTriggers)
+   *
+   * @param redirectStream
+   *          if null, redirection is disabled
+   * @param redirectTriggers
+   *          All startElement events occuring in this list will trigger
+   *          redirection of the entire fragment. If null, all events are
+   *          redirected
+   */
+  // public void setRedirectStream(OutputStream redirectStream, List<QName>
+  // redirectTriggers) throws XMLStreamException {
+  // if (redirectStream != null) {
+  // XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
+  // redirectWriter = outputFactory.createXMLEventWriter(redirectStream);
+  // } else {
+  // redirectWriter = null;
+  // }
+  // this.redirectTriggers = (redirectStream == null) ? null : redirectTriggers;
+  // }
+  /**
+   * flushes the internal EventWriter
+   *
+   * @throws javax.xml.stream.XMLStreamException
+   */
+  public void flushRedirectStream() throws XMLStreamException {
+    redirectWriter.flush();
+  }
+
+  /**
+   * the namespaceContext of the last startelement event read
+   *
+   * @return
+   */
+  public NamespaceContext getCurrentNamespaceContext() {
+    return currentNamespaceContext;
+  }
+}