package org.apache.velocity.util.introspection;
/*
* Copyright 2002-2006 The Apache Software Foundation.
*
* 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.
*/
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import org.apache.velocity.runtime.RuntimeLogger;
import org.apache.velocity.runtime.log.Log;
import org.apache.velocity.runtime.log.RuntimeLoggerLog;
import org.apache.velocity.runtime.parser.node.AbstractExecutor;
import org.apache.velocity.runtime.parser.node.BooleanPropertyExecutor;
import org.apache.velocity.runtime.parser.node.GetExecutor;
import org.apache.velocity.runtime.parser.node.PropertyExecutor;
import org.apache.velocity.runtime.parser.node.PutExecutor;
import org.apache.velocity.runtime.parser.node.SetExecutor;
import org.apache.velocity.runtime.parser.node.SetPropertyExecutor;
import org.apache.velocity.util.ArrayIterator;
import org.apache.velocity.util.EnumerationIterator;
/**
* Implementation of Uberspect to provide the default introspective
* functionality of Velocity
*
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
* @version $Id: UberspectImpl.java 440737 2006-09-06 15:37:44Z henning $
*/
public class UberspectImpl implements Uberspect, UberspectLoggable
{
/**
* Our runtime logger.
*/
private Log log;
/**
* the default Velocity introspector
*/
protected Introspector introspector;
/**
* init - generates the Introspector. As the setup code
* makes sure that the log gets set before this is called,
* we can initialize the Introspector using the log object.
*/
public void init()
{
introspector = new Introspector(log);
}
/**
* Sets the runtime logger - this must be called before anything
* else.
*
* @param log The logger instance to use.
*/
public void setLog(Log log)
{
this.log = log;
}
/**
* @deprecated Use setLog(Log log) instead.
*/
public void setRuntimeLogger(RuntimeLogger runtimeLogger)
{
// in the off chance anyone still uses this method
// directly, use this hack to keep it working
setLog(new RuntimeLoggerLog(runtimeLogger));
}
/**
* To support iterative objects used in a <code>#foreach()</code>
* loop.
*
* @param obj The iterative object.
* @param i Info about the object's location.
*/
public Iterator getIterator(Object obj, Info i)
throws Exception
{
if (obj.getClass().isArray())
{
return new ArrayIterator(obj);
}
else if (obj instanceof Collection)
{
return ((Collection) obj).iterator();
}
else if (obj instanceof Map)
{
return ((Map) obj).values().iterator();
}
else if (obj instanceof Iterator)
{
if (log.isDebugEnabled())
{
log.debug("The iterative object in the #foreach() loop at " +
i + " is of type java.util.Iterator. Because " +
"it is not resettable, if used in more than once it " +
"may lead to unexpected results.");
}
return ((Iterator) obj);
}
else if (obj instanceof Enumeration)
{
if (log.isDebugEnabled())
{
log.debug("The iterative object in the #foreach() loop at " +
i + " is of type java.util.Enumeration. Because " +
"it is not resettable, if used in more than once it " +
"may lead to unexpected results.");
}
return new EnumerationIterator((Enumeration) obj);
}
/* we have no clue what this is */
log.info("Could not determine type of iterator in #foreach loop at " + i);
return null;
}
/**
* Method
*/
public VelMethod getMethod(Object obj, String methodName, Object[] args, Info i)
throws Exception
{
if (obj == null)
{
return null;
}
Method m = introspector.getMethod(obj.getClass(), methodName, args);
return (m != null) ? new VelMethodImpl(m) : null;
}
/**
* Property getter
*/
public VelPropertyGet getPropertyGet(Object obj, String identifier, Info i)
throws Exception
{
if (obj == null)
{
return null;
}
Class claz = obj.getClass();
/*
* first try for a getFoo() type of property
* (also getfoo() )
*/
AbstractExecutor executor = new PropertyExecutor(log, introspector, claz, identifier);
/*
* if that didn't work, look for get("foo")
*/
if (!executor.isAlive())
{
executor = new GetExecutor(log, introspector, claz, identifier);
}
/*
* finally, look for boolean isFoo()
*/
if (!executor.isAlive())
{
executor = new BooleanPropertyExecutor(log, introspector, claz,
identifier);
}
return (executor.isAlive()) ? new VelGetterImpl(executor) : null;
}
/**
* Property setter
*/
public VelPropertySet getPropertySet(Object obj, String identifier,
Object arg, Info i)
throws Exception
{
if (obj == null)
{
return null;
}
Class claz = obj.getClass();
/*
* first try for a setFoo() type of property
* (also setfoo() )
*/
SetExecutor executor = new SetPropertyExecutor(log, introspector, claz, identifier, arg);
/*
* if that didn't work, look for put("foo", arg)
*/
if (!executor.isAlive())
{
executor = new PutExecutor(log, introspector, claz, arg, identifier);
}
return (executor.isAlive()) ? new VelSetterImpl(executor) : null;
}
/**
* Implementation of VelMethod
*/
public static class VelMethodImpl implements VelMethod
{
final Method method;
public VelMethodImpl(Method m)
{
method = m;
}
private VelMethodImpl()
{
method = null;
}
public Object invoke(Object o, Object[] params)
throws Exception
{
return method.invoke(o, params);
}
public boolean isCacheable()
{
return true;
}
public String getMethodName()
{
return method.getName();
}
public Class getReturnType()
{
return method.getReturnType();
}
}
public static class VelGetterImpl implements VelPropertyGet
{
final AbstractExecutor getExecutor;
public VelGetterImpl(AbstractExecutor exec)
{
getExecutor = exec;
}
private VelGetterImpl()
{
getExecutor = null;
}
public Object invoke(Object o)
throws Exception
{
return getExecutor.execute(o);
}
public boolean isCacheable()
{
return true;
}
public String getMethodName()
{
return getExecutor.isAlive() ? getExecutor.getMethod().getName() : null;
}
}
public static class VelSetterImpl implements VelPropertySet
{
private final SetExecutor setExecutor;
public VelSetterImpl(final SetExecutor setExecutor)
{
this.setExecutor = setExecutor;
}
private VelSetterImpl()
{
setExecutor = null;
}
/**
* Invoke the found Set Executor.
*
* @param o is the Object to invoke it on.
* @param value in the Value to set.
*/
public Object invoke(final Object o, final Object value)
throws Exception
{
return setExecutor.execute(o, value);
}
public boolean isCacheable()
{
return true;
}
public String getMethodName()
{
return setExecutor.isAlive() ? setExecutor.getMethod().getName() : null;
}
}
}