Author: jukka
Date: Mon Jun 1 22:09:54 2009
New Revision: 780852
URL: http://svn.apache.org/viewvc?rev=780852&view=rev
Log:
TIKA-237: Better distinction between SAXException and TikaException
Add TaggedContentHandler wrapper class based on the design of the similar
TaggedInputStream feature.
Added:
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedContentHandler.java
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedSAXException.java
Modified:
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/ContentHandlerDecorator.java
Modified:
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/ContentHandlerDecorator.java
URL:
http://svn.apache.org/viewvc/lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/ContentHandlerDecorator.java?rev=780852&r1=780851&r2=780852&view=diff
==============================================================================
---
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/ContentHandlerDecorator.java
(original)
+++
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/ContentHandlerDecorator.java
Mon Jun 1 22:09:54 2009
@@ -44,58 +44,124 @@
this.handler = handler;
}
+ @Override
public void startPrefixMapping(String prefix, String uri)
throws SAXException {
- handler.startPrefixMapping(prefix, uri);
+ try {
+ handler.startPrefixMapping(prefix, uri);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void endPrefixMapping(String prefix) throws SAXException {
- handler.endPrefixMapping(prefix);
+ try {
+ handler.endPrefixMapping(prefix);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void processingInstruction(String target, String data)
throws SAXException {
- handler.processingInstruction(target, data);
+ try {
+ handler.processingInstruction(target, data);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void setDocumentLocator(Locator locator) {
handler.setDocumentLocator(locator);
}
+ @Override
public void startDocument() throws SAXException {
- handler.startDocument();
+ try {
+ handler.startDocument();
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void endDocument() throws SAXException {
- handler.endDocument();
+ try {
+ handler.endDocument();
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
- public void startElement(String uri, String localName, String name,
- Attributes atts) throws SAXException {
- handler.startElement(uri, localName, name, atts);
+ @Override
+ public void startElement(
+ String uri, String localName, String name, Attributes atts)
+ throws SAXException {
+ try {
+ handler.startElement(uri, localName, name, atts);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void endElement(String uri, String localName, String name)
throws SAXException {
- handler.endElement(uri, localName, name);
+ try {
+ handler.endElement(uri, localName, name);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void characters(char[] ch, int start, int length)
throws SAXException {
- handler.characters(ch, start, length);
+ try {
+ handler.characters(ch, start, length);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void ignorableWhitespace(char[] ch, int start, int length)
throws SAXException {
- handler.ignorableWhitespace(ch, start, length);
+ try {
+ handler.ignorableWhitespace(ch, start, length);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public void skippedEntity(String name) throws SAXException {
- handler.skippedEntity(name);
+ try {
+ handler.skippedEntity(name);
+ } catch (SAXException e) {
+ handleException(e);
+ }
}
+ @Override
public String toString() {
return handler.toString();
}
+ /**
+ * Handle any exceptions thrown by methods in this class. This method
+ * provides a single place to implement custom exception handling. The
+ * default behaviour is simply to re-throw the given exception, but
+ * subclasses can also provide alternative ways of handling the situation.
+ *
+ * @param exception the exception that was thrown
+ * @throws SAXException the exception (if any) thrown to the client
+ */
+ protected void handleException(SAXException exception) throws SAXException
{
+ throw exception;
+ }
+
}
Added:
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedContentHandler.java
URL:
http://svn.apache.org/viewvc/lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedContentHandler.java?rev=780852&view=auto
==============================================================================
---
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedContentHandler.java
(added)
+++
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedContentHandler.java
Mon Jun 1 22:09:54 2009
@@ -0,0 +1,116 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.tika.sax;
+
+import org.xml.sax.ContentHandler;
+import org.xml.sax.SAXException;
+
+/**
+ * A content handler decorator that tags potential exceptions so that the
+ * handler that caused the exception can easily be identified. This is
+ * done by using the {...@link TaggedSAXException} class to wrap all thrown
+ * {...@link SAXException}s. See below for an example of using this class.
+ * <pre>
+ * TaggedContentHandler handler = new TaggedContentHandler(...);
+ * try {
+ * // Processing that may throw an SAXException either from this handler
+ * // or from some other XML parsing activity
+ * processXML(handler);
+ * } catch (SAXException e) {
+ * if (handler.isCauseOf(e)) {
+ * // The exception was caused by this handler.
+ * // Use e.getCause() to get the original exception.
+ * } else {
+ * // The exception was caused by something else.
+ * }
+ * }
+ * </pre>
+ * <p>
+ * Alternatively, the {...@link #throwIfCauseOf(Exception)} method can be
+ * used to let higher levels of code handle the exception caused by this
+ * stream while other processing errors are being taken care of at this
+ * lower level.
+ * <pre>
+ * TaggedContentHandler handler = new TaggedContentHandler(...);
+ * try {
+ * processXML(handler);
+ * } catch (SAXException e) {
+ * stream.throwIfCauseOf(e);
+ * // ... or process the exception that was caused by something else
+ * }
+ * </pre>
+ *
+ * @see TaggedSAXException
+ */
+public class TaggedContentHandler extends ContentHandlerDecorator {
+
+ /**
+ * Creates a tagging decorator for the given content handler.
+ *
+ * @param proxy content handler to be decorated
+ */
+ public TaggedContentHandler(ContentHandler proxy) {
+ super(proxy);
+ }
+
+ /**
+ * Tests if the given exception was caused by this handler.
+ *
+ * @param exception an exception
+ * @return <code>true</code> if the exception was thrown by this handler,
+ * <code>false</code> otherwise
+ */
+ public boolean isCauseOf(SAXException exception) {
+ if (exception instanceof TaggedSAXException) {
+ TaggedSAXException tagged = (TaggedSAXException) exception;
+ return this == tagged.getTag();
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * Re-throws the original exception thrown by this handler. This method
+ * first checks whether the given exception is a {...@link
TaggedSAXException}
+ * wrapper created by this decorator, and then unwraps and throws the
+ * original wrapped exception. Returns normally if the exception was
+ * not thrown by this handler.
+ *
+ * @param exception an exception
+ * @throws SAXException original exception, if any, thrown by this handler
+ */
+ public void throwIfCauseOf(Exception exception) throws SAXException {
+ if (exception instanceof TaggedSAXException) {
+ TaggedSAXException tagged = (TaggedSAXException) exception;
+ if (this == tagged.getTag()) {
+ throw tagged.getCause();
+ }
+ }
+ }
+
+ /**
+ * Tags any {...@link SAXException}s thrown, wrapping and re-throwing.
+ *
+ * @param e The SAXException thrown
+ * @throws SAXException if an XML error occurs
+ */
+ @Override
+ protected void handleException(SAXException e) throws SAXException {
+ throw new TaggedSAXException(e, this);
+ }
+
+}
Added:
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedSAXException.java
URL:
http://svn.apache.org/viewvc/lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedSAXException.java?rev=780852&view=auto
==============================================================================
---
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedSAXException.java
(added)
+++
lucene/tika/trunk/tika-core/src/main/java/org/apache/tika/sax/TaggedSAXException.java
Mon Jun 1 22:09:54 2009
@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.tika.sax;
+
+import org.xml.sax.SAXException;
+
+/**
+ * A {...@link SAXException} wrapper that tags the wrapped exception with
+ * a given object reference. Both the tag and the wrapped original exception
+ * can be used to determine further processing when this exception is caught.
+ */
+public class TaggedSAXException extends SAXException {
+
+ /**
+ * The object reference used to tag the exception.
+ */
+ private final Object tag;
+
+ /**
+ * Creates a tagged wrapper for the given exception.
+ *
+ * @param original the exception to be tagged
+ * @param tag tag object
+ */
+ public TaggedSAXException(SAXException original, Object tag) {
+ super(original.getMessage(), original);
+ this.tag = tag;
+ }
+
+ /**
+ * Returns the object reference used as the tag this exception.
+ *
+ * @return tag object
+ */
+ public Object getTag() {
+ return tag;
+ }
+
+ /**
+ * Returns the wrapped exception. The only difference to the overridden
+ * {...@link Throwable#getCause()} method is the narrower return type.
+ *
+ * @return wrapped exception
+ */
+ @Override
+ public SAXException getCause() {
+ return (SAXException) super.getCause();
+ }
+
+}
