ovidiu 02/03/17 13:43:37
Added: src/scratchpad/schecoon/src/org/apache/cocoon/components/flow
AbstractInterpreter.java
Log:
Super class for flow language interpreters. Deals mainly with
observing modifications to script files used, and reloads them in the
interpreter if they modify.
Revision Changes Path
1.1
xml-cocoon2/src/scratchpad/schecoon/src/org/apache/cocoon/components/flow/AbstractInterpreter.java
Index: AbstractInterpreter.java
===================================================================
package org.apache.cocoon.components.flow;
import java.lang.System;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.component.Component;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.Composable;
import org.apache.avalon.framework.context.ContextException;
import org.apache.avalon.framework.context.Contextualizable;
import org.apache.avalon.framework.logger.AbstractLoggable;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.Constants;
import org.apache.cocoon.components.source.SourceFactory;
import org.apache.cocoon.environment.Context;
import org.apache.cocoon.environment.Environment;
import org.apache.cocoon.environment.ModifiableSource;
import org.apache.cocoon.environment.Source;
import org.apache.cocoon.environment.SourceResolver;
/**
* Abstract superclass for various scripting languages used by Cocoon
* for flow control. Defines some useful behavior like the ability to
* reload script files if they get modified (useful when doing
* development).
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Ovidiu Predescu</a>
* @since March 15, 2002
*/
public abstract class AbstractInterpreter extends AbstractLoggable
implements Component, Composable, Contextualizable, Interpreter, ThreadSafe
{
/**
* Hash table of source locations -> DelayedRefreshSourceWrapper
* instances
*/
protected HashMap scripts = new HashMap();
/**
* List of source locations that need to be resolved.
*/
protected ArrayList needResolve = new ArrayList();
/**
* When was the last time we checked for script modifications. Used
* only if {@link reloadScripts} is true.
*/
protected long lastTimeCheck = 0;
protected org.apache.cocoon.environment.Context context;
protected ComponentManager manager;
/**
* Whether reloading of scripts should be done. Specified through
* the "reload-scripts" attribute in <code>flow.xmap</code>.
*/
protected boolean reloadScripts;
/**
* Interval between two checks for modified script files. Specified
* through the "check-time" XML attribute in <code>flow.xmap</code>.
*/
protected long checkTime;
public void compose(ComponentManager manager)
{
this.manager = manager;
}
public void contextualize(org.apache.avalon.framework.context.Context context)
throws ContextException
{
this.context = (Context)context.get(Constants.CONTEXT_ENVIRONMENT_CONTEXT);
}
public void setReloadScripts(boolean yn)
{
reloadScripts = yn;
}
public void setCheckTime(long time)
{
checkTime = time;
}
/**
* Registers a source file with the interpreter. Using this method
* an implementation keeps track of all the script files which are
* compiled. This allows them to reload the script files which get
* modified on the file system.
*
* <p>The parsing/compilation of a script file by an interpreter
* happens in two phases. In the first phase the file's location is
* registered in the <code>needResolve</code> array.
*
* <p>The second is possible only when a Cocoon
* <code>Environment</code> is passed to the Interpreter. This
* allows the file location to be resolved using Cocoon's
* <code>SourceFactory</code> class.
*
* <p>Once a file's location can be resolved, it is removed from the
* <code>needResolve</code> array and placed in the
* <code>scripts</code> hash table. The key in this hash table is
* the file location string, and the value is a
* DelayedRefreshSourceWrapper instance which keeps track of when
* the file needs to re-read.
*
* @param source the location of the script
*
* @see org.apache.cocoon.components.source.SourceFactory
* @see org.apache.cocoon.environment.Environment
* @see org.apache.cocoon.components.source.DelayedRefreshSourceWrapper
*/
public void register(String source)
{
synchronized(this) {
needResolve.add(source);
}
}
/**
* Unregister the source file. Called from <code>ScriptNode</code>
* when a tree corresponding to a sitemap is decommissioned.
*
* @param source a <code>String</code> value
*/
public void unregister(String source)
{
synchronized(this) {
scripts.remove(source);
int index = needResolve.indexOf(source);
if (index != -1)
needResolve.remove(index);
}
}
/**
* Reloads any modified script files.
*
* <p>It checks to see if any of the files already read in (those
* present in the <code>scripts</code> hash map) have been
* modified.
*
* <p>It also checks to see if any script files have been registered
* with the interpreter since the last call to
* <code>checkForModifiedScripts</code>. These files are stored in
* the temporary array <code>needResolve</code>. If any such files
* are found, they are read in.
*
* @param environment an <code>Environment</code> value
*/
public void checkForModifiedScripts(Environment environment)
throws Exception
{
if (reloadScripts
&& System.currentTimeMillis() >= lastTimeCheck + checkTime) {
// FIXME: should we worry about synchronization?
Iterator iter = scripts.values().iterator();
while (iter.hasNext()) {
ScriptSource src = (ScriptSource)iter.next();
if (src.getLastModified() > lastTimeCheck)
src.refresh(environment);
}
}
int size = needResolve.size();
if (size > 0) {
synchronized (this) {
size = needResolve.size();
for (int i = size - 1; i >= 0; i--) {
String source = (String)needResolve.get(i);
ScriptSource src = new ScriptSource(this, source);
scripts.put(source, src);
needResolve.remove(i);
src.refresh(environment);
}
}
}
// Update the time of the last check. If an exception occurs, this
// is not executed, so the next request will force a reparse of
// the script files because of an old time stamp.
lastTimeCheck = System.currentTimeMillis();
}
}
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