/*
* 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.input;
import org.apache.avalon.framework.CascadingRuntimeException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.ComponentSelector;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.ServiceSelector;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* @author <a href="mailto:haul@apache.org">Christian Haul</a>
* @version $Id$
*/
public class InputModuleHelper {
// TODO consolidate code with AbstractMetaModule to use this class as delegate
protected final static String INPUT_MODULE_SELECTOR = InputModule.ROLE+"Selector";
/* Operation codes */
private final static int OP_GET = 0;
private final static int OP_VALUES = 1;
private final static int OP_NAMES = 2;
private Map inputModules;
private ComponentManager componentManager;
private ComponentSelector componentInputSelector;
private ServiceManager serviceManager;
private ServiceSelector serviceInputSelector;
/**
* Get the input module
*/
private InputModule getInputModule(String name)
throws CascadingRuntimeException {
if ( this.inputModules == null ) {
throw new RuntimeException("ModuleHelper is not setup correctly.");
}
InputModule module = (InputModule) this.inputModules.get(name);
if ( module == null ) {
try {
if ( this.componentManager != null ) {
if (this.componentInputSelector.hasComponent(name)) {
module = (InputModule) this.componentInputSelector.select(name);
}
} else {
if (this.serviceInputSelector.isSelectable(name)) {
module = (InputModule) this.serviceInputSelector.select(name);
}
}
} catch (Exception e) {
throw new CascadingRuntimeException("Unable to lookup input module " + name, e);
}
if ( module == null ) {
throw new RuntimeException("No such InputModule: "+name);
}
this.inputModules.put(name, module);
}
return module;
}
/**
* Capsules use of an InputModule. Does all the lookups and so
* on. Returns either an Object, an Object[], or an Iterator,
* depending on the method called i.e. the op specified. The
* second module is preferred and has an non null name. If an
* exception is encountered, a warn message is printed and null is
* returned.
* @param op an <code>int</code> value encoding the desired operation
* @param name a <code>String</code> value holding the name of the
* InputModule
* @param attr a <code>String</code> value holding the name of the
* attribute to return. Is disregarded when attribute names is
* requested.
* @param objectModel a <code>Map</code> value holding the current
* ObjectModel
* @return an <code>Object</code> value
* @exception CascadingRuntimeException if an error occurs. The real
* exception can be obtained with <code>getCause</code>.
*/
private Object get(int op, String name, String attr, Map objectModel, Configuration conf) throws CascadingRuntimeException {
Object value = null;
final InputModule input = this.getInputModule(name);
try {
switch (op) {
case OP_GET:
value = input.getAttribute(attr, conf, objectModel);
break;
case OP_VALUES:
value = input.getAttributeValues(attr, conf, objectModel);
break;
case OP_NAMES:
value = input.getAttributeNames(conf, objectModel);
break;
}
} catch (Exception e) {
throw new CascadingRuntimeException("Error accessing attribute '"+attr+"' from input module '"+name+"'. "+e.getMessage(), e);
}
return value;
}
private Object get(int op, String name, String attr, Map objectModel) throws RuntimeException {
return get(op, name, attr, objectModel, null);
}
/**
* Initializes the instance for first use. Stores references to
* component manager and component selector in instance
*
* @param manager a <code>ComponentManager</code> value
* @exception RuntimeException if an error occurs
* @deprecated Use the {@link #setup(ServiceManager)} method instead
*/
public void setup(ComponentManager manager) throws RuntimeException {
this.inputModules = new HashMap();
this.componentManager = manager;
try {
this.componentInputSelector = (ComponentSelector) this.componentManager.lookup(INPUT_MODULE_SELECTOR);
} catch (Exception e) {
throw new CascadingRuntimeException("Could not obtain selector for InputModule.",e);
}
}
/**
* Initializes the instance for first use. Stores references to
* service manager and service selector in instance
*
* @param manager a <code>ServiceManager</code> value
* @exception RuntimeException if an error occurs
*/
public void setup(ServiceManager manager) throws RuntimeException {
this.inputModules = new HashMap();
this.serviceManager = manager;
try {
this.serviceInputSelector = (ServiceSelector) this.serviceManager.lookup(INPUT_MODULE_SELECTOR);
} catch (Exception e) {
throw new CascadingRuntimeException("Could not obtain selector for InputModule.",e);
}
}
/**
* Get a single attribute value from a module. Uses cached
* reference if existing.
*
* @param objectModel a <code>Map</code> value
* @param conf a <code>Configuration</code> containing the module dynamic configuration (aka modeConf)
* @param module a <code>String</code> value holding the module name
* @param name a <code>String</code> value holding the attribute name
* @param deflt an <code>Object</code> value holding a default value
* @return an <code>Object</code> value
* @exception RuntimeException if an error occurs
*/
public Object getAttribute(Map objectModel, Configuration conf, String module, String name, Object deflt) throws RuntimeException {
Object result = this.get(OP_GET, module, name, objectModel, conf);
if (result == null) result = deflt;
return result;
}
/**
* Get a single attribute value from a module. Same as {@link
* #getAttribute(Map, Configuration, String, String, Object)} with a
* <code>null</code> configuration.
*/
public Object getAttribute(Map objectModel, String module, String name, Object deflt) throws RuntimeException {
return getAttribute(objectModel, null, module, name, deflt);
}
/**
* Get an array of values from a module. Uses cached reference if
* existing.
*
* @param objectModel a <code>Map</code> value
* @param conf a <code>Configuration</code> containing the module dynamic configuration (aka modeConf)
* @param module a <code>String</code> value holding the module name
* @param name a <code>String</code> value holding the attribute name
* @param deflt an <code>Object[]</code> value holding a default value
* @return an <code>Object[]</code> value
* @exception RuntimeException if an error occurs
*/
public Object[] getAttributeValues(Map objectModel, Configuration conf, String module, String name, Object[] deflt) throws RuntimeException {
Object[] result = (Object[]) this.get(OP_VALUES, module, name, objectModel, conf);
if (result == null) result = deflt;
return result;
}
/**
* Get an array of values from a module. Same as
* {@link #getAttributeValues(Map, Configuration, String, String, Object[])}
* with a <code>null</code> configuration.
*/
public Object[] getAttributeValues(Map objectModel, String module, String name, Object[] deflt) throws RuntimeException {
return getAttributeValues(objectModel, null, module, name, deflt);
}
/**
* Get an iterator to a collection of attribute names from a
* module.
*
* @param objectModel a <code>Map</code> value
* @param module the module's name
* @return an <code>Iterator</code> value
* @exception RuntimeException if an error occurs
*/
public Iterator getAttributeNames(Map objectModel, Configuration conf, String module) throws RuntimeException {
return (Iterator) this.get(OP_NAMES, module, null, objectModel);
}
/** Get an iterator to a collection of attribute names from a module. Same
* as {@link #getAttributeNames(Map, Configuration, String)} with a
* <code>null</code> configuration.
*/
public Iterator getAttributeNames(Map objectModel, String module) throws RuntimeException {
return getAttributeNames(objectModel, (Configuration)null, module);
}
/**
* Releases all obtained module references.
*
* @exception RuntimeException if an error occurs
*/
public void releaseAll() throws RuntimeException {
if ( this.inputModules != null ) {
// test for component manager
if ( this.componentManager != null ) {
try {
Iterator iter = this.inputModules.keySet().iterator();
while (iter.hasNext()) {
this.componentInputSelector.release((InputModule) this.inputModules.get(iter.next()));
}
this.inputModules = null;
this.componentManager.release(this.componentInputSelector);
this.componentManager = null;
this.inputModules = null;
} catch (Exception e) {
throw new CascadingRuntimeException("Could not release InputModules.",e);
}
}
if ( this.serviceManager != null ) {
try {
Iterator iter = this.inputModules.keySet().iterator();
while (iter.hasNext()) {
this.serviceInputSelector.release(this.inputModules.get(iter.next()));
}
this.inputModules = null;
this.serviceManager.release(this.serviceInputSelector);
this.serviceManager = null;
this.inputModules = null;
} catch (Exception e) {
throw new CascadingRuntimeException("Could not release InputModules.",e);
}
}
}
}
}