/*
* Copyright 1999-2004 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.
*/
package org.apache.cocoon.components.language.programming;
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.context.ContextException;
import org.apache.avalon.framework.context.Contextualizable;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.parameters.ParameterException;
import org.apache.cocoon.Constants;
import org.apache.cocoon.components.language.LanguageException;
import org.apache.cocoon.components.language.programming.java.JavaProgram;
import org.apache.cocoon.util.ClassUtils;
import org.apache.cocoon.util.IOUtils;
import java.io.File;
/**
* A compiled programming language. This class extends <code>AbstractProgrammingLanguage</code> adding support for compilation
* and object program files
* @author <a href="mailto:ricardo@apache.org">Ricardo Rocha</a>
* @version CVS $Id: CompiledProgrammingLanguage.java 30932 2004-07-29 17:35:38Z vgritsenko $
*/
public abstract class CompiledProgrammingLanguage extends AbstractProgrammingLanguage implements Contextualizable {
/** The compiler */
protected Class compilerClass;
/** The local classpath */
protected String classpath;
/** The source deletion option */
protected boolean deleteSources = false;
/**
* Set the configuration parameters. This method instantiates the sitemap-specified language compiler
* @param params The configuration parameters
* @exception ParameterException If the language compiler cannot be loaded
*/
public void parameterize(Parameters params) throws ParameterException {
super.parameterize(params);
String compilerClass = params.getParameter("compiler");
try {
this.compilerClass = ClassUtils.loadClass(compilerClass);
} catch (ClassNotFoundException e) {
throw new ParameterException("Unable to load compiler: " + compilerClass, e);
}
this.deleteSources = params.getParameterAsBoolean("delete-sources", false);
}
/**
* Set the context
* @param context The context
*/
public void contextualize(Context context) throws ContextException {
this.classpath = (String) context.get(Constants.CONTEXT_CLASSPATH);
}
/**
* Return the language's canonical object file extension.
* @return The object file extension
*/
public abstract String getObjectExtension();
/**
* Unload a previously loaded program
* @param program A previously loaded object program
* @exception LanguageException If an error occurs during unloading
*/
public abstract void doUnload(Object program) throws LanguageException;
/**
* Unload a previously loaded program given its original filesystem location
* @param program The previously loaded object program
* @param filename The base filename of the object program
* @param baseDirectory The directory contaning the object program file
* @exception LanguageException If an error occurs
*/
protected final void doUnload(Object program, String filename, File baseDirectory) throws LanguageException {
int index = filename.lastIndexOf(File.separator);
String dir = filename.substring(0, index);
String file = filename.substring(index + 1);
File baseDir = new File(baseDirectory, dir);
File[] files = baseDir.listFiles();
for (int i = 0;(files != null) && (i < files.length); i++) {
if (files[i].getName().startsWith(file)) {
files[i].delete();
}
}
this.doUnload(program);
}
/**
* Actually load an object program from a file.
* @param filename The object program base file name
* @param baseDirectory The directory containing the object program file
* @return The loaded object program
* @exception LanguageException If an error occurs during loading
*/
protected abstract Class loadProgram(String filename, File baseDirectory) throws LanguageException;
/**
* Compile a source file yielding a loadable object file.
* @param filename The object program base file name
* @param baseDirectory The directory containing the object program file
* @param encoding The encoding expected in the source file or <code>null</code> if it is the platform's default encoding
* @exception LanguageException If an error occurs during compilation
*/
protected abstract void compile(String filename, File baseDirectory, String encoding) throws LanguageException;
/**
* Preload an object program from a file.
* This method does not compiles the corresponding source file.
*
* @param filename The object program base file name
* @param baseDirectory The directory containing the object program file
* @param encoding The encoding expected in the source file or <code>null</code> if it is the platform's default encoding
* @return The loaded object program
* @exception LanguageException If an error occurs during compilation
*/
public Program preload(String filename, File baseDirectory, String encoding) throws LanguageException {
// Don't need to test for existence of the object code as it might be bundled into the WAR.
try {
Class program = this.loadProgram(filename, baseDirectory);
// Create and discard test instance.
program.newInstance();
return new JavaProgram(program);
} catch (Throwable t) {
throw new LanguageException("Unable to preload program " + filename, t);
}
}
/**
* Load an object program from a file.
* This method compiles the corresponding source file if necessary.
*
* @param filename The object program base file name
* @param baseDirectory The directory containing the object program file
* @param encoding The encoding expected in the source file or <code>null</code> if it is the platform's default encoding
* @return The loaded object program
* @exception LanguageException If an error occurs during compilation
*/
public Program load(String filename, File baseDirectory, String encoding) throws LanguageException {
// Does source file exist?
File sourceFile = new File(baseDirectory, filename + "." + this.getSourceExtension());
if (!sourceFile.exists()) {
throw new LanguageException("Can't load program - File doesn't exist: " + IOUtils.getFullFilename(sourceFile));
}
if (!sourceFile.isFile()) {
throw new LanguageException("Can't load program - File is not a normal file: " + IOUtils.getFullFilename(sourceFile));
}
if (!sourceFile.canRead()) {
throw new LanguageException("Can't load program - File cannot be read: " + IOUtils.getFullFilename(sourceFile));
}
this.compile(filename, baseDirectory, encoding);
if (this.deleteSources) {
sourceFile.delete();
}
Class program = this.loadProgram(filename, baseDirectory);
// Try to instantiate once to ensure there are no exceptions thrown in the constructor
try {
// Create and discard test instance
program.newInstance();
} catch(IllegalAccessException iae) {
getLogger().debug("No public constructor for class " + program.getName());
} catch(Exception e) {
// Unload class and delete the object file, or it won't be recompiled
// (leave the source file to allow examination).
this.doUnload(program);
new File(baseDirectory, filename + "." + this.getObjectExtension()).delete();
String message = "Error while instantiating " + filename;
getLogger().debug(message, e);
throw new LanguageException(message, e);
}
if (program == null) {
throw new LanguageException("Can't load program : " + baseDirectory.toString() + File.separator + filename);
}
return new JavaProgram(program);
}
}