/*
* 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.cocoon.components.modules.output;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.environment.Request;
import java.util.Iterator;
import java.util.Map;
/**
* Abstraction layer to encapsulate different output
* destinations. Configuration option <key-prefix> defaults to
* <code>"org.apache.cocoon.components.modules.output.OutputModule" + ":"</code>
*
* <p>Can be used with different isolation-level: default is "0" being
* no isolation at all, values are immediately visible but are removed
* on a rollback; "1" keeps the values at a safe place until either
* rollback or commit is called. Then values are either discarded or
* copied to the final destination.</p>
*
* @author <a href="mailto:haul@apache.org">Christian Haul</a>
* @version CVS $Id$
*/
public class RequestAttributeOutputModule extends AbstractOutputModule {
public static final String PREFIX = OutputModule.ROLE;
public static final String TRANS_PREFIX = PREFIX + ".RequestAttributeOutputModule.transient";
public static final String ROLLBACK_LIST = PREFIX + ".RequestAttributeOutputModule.rollback";
/**
* communicate an attribute value to further processing logic.
* @param modeConf column's mode configuration from resource
* description. This argument is optional.
* @param objectModel The objectModel
* @param name The attribute's label, consisting of "table.column"
* or "table.column[index]" in case of multiple attributes
* of the same spec.
* @param value The attriute's value.
*/
public void setAttribute(Configuration modeConf, Map objectModel, String name, Object value) {
if (this.settings.get("isolation-level", "0").equals("1")) {
// Read committed isolation level
if (getLogger().isDebugEnabled()) {
getLogger().debug("Setting transient ['" + name + "'] to ['" + value + "']");
}
transientSetAttribute(objectModel, TRANS_PREFIX, name, value);
} else {
// Read uncommitted isolation level
final Request request = ObjectModelHelper.getRequest(objectModel);
name = getName(name);
if (!attributeExists(objectModel, ROLLBACK_LIST, name)) {
Object tmp = request.getAttribute(name);
transientSetAttribute(objectModel, ROLLBACK_LIST, name, tmp);
}
if (getLogger().isDebugEnabled()) {
getLogger().debug("Setting ['" + name + "'] to ['" + value + "']");
}
request.setAttribute(name, value);
}
}
/**
* If a database transaction needs to rollback, this is called to
* inform the further processing logic about this fact. All
* already set attribute values are invalidated.
*
* <em>This is difficult
* because only the request object can be used to synchronize this
* and build some kind of transaction object. Beware that sending
* your data straight to some beans or other entities could result
* in data corruption!</em>
*/
public void rollback(Configuration modeConf, Map objectModel, Exception e) {
getLogger().debug("Rollback");
final Request request = ObjectModelHelper.getRequest(objectModel);
if (this.settings.get("isolation-level", "0").equals("1")) {
rollback(objectModel, TRANS_PREFIX);
} else {
Map rollbackList = prepareCommit(objectModel, ROLLBACK_LIST);
if (rollbackList != null) {
for (Iterator i = rollbackList.entrySet().iterator(); i.hasNext();) {
final Map.Entry me = (Map.Entry) i.next();
String key = (String) me.getKey();
Object val = me.getValue();
if (val != null) {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Rolling back ['" + key + "'] to ['" + val + "']");
}
request.setAttribute(key, val);
} else {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Rolling back ['" + key + "']");
}
request.removeAttribute(key);
}
}
}
}
String prefix = (String) this.settings.get("key-prefix", PREFIX);
if (prefix.length() == 0) {
request.setAttribute("errorMessage", e.getMessage());
} else {
request.setAttribute(prefix + ':' + "errorMessage", e.getMessage());
}
}
/**
* Signal that the database transaction completed
* successfully. See notes on @link{rollback}.
*/
public void commit(Configuration modeConf, Map objectModel) {
getLogger().debug("Commit");
if (this.settings.get("isolation-level", "0").equals("1")) {
Map data = prepareCommit(objectModel, TRANS_PREFIX);
if (data == null || data.isEmpty()) {
return;
}
String prefix = (String) this.settings.get("key-prefix", PREFIX);
if (prefix.length() == 0) {
prefix = null;
}
Request request = ObjectModelHelper.getRequest(objectModel);
for (Iterator i = data.entrySet().iterator(); i.hasNext();) {
final Map.Entry me = (Map.Entry) i.next();
String key = (String) me.getKey();
Object value = me.getValue();
if (prefix != null) {
key = prefix + ':' + key;
}
if (getLogger().isDebugEnabled()) {
getLogger().debug("Committing ['" + key + "'] to ['" + value + "']");
}
request.setAttribute(key, value);
}
} else {
prepareCommit(objectModel, ROLLBACK_LIST);
}
}
protected String getName(String name) {
String prefix = (String) this.settings.get("key-prefix", PREFIX);
return prefix.length() == 0 ? name : prefix + ':' + name;
}
}