Ant example source code file (JspCompilerAdapterFactory.java)

This example Ant source code file (JspCompilerAdapterFactory.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

antclassloader, antclassloader, buildexception, buildexception, jasper41mangler, jasperc, jasperc, jspcompileradapter, jspcompileradapter, jspcompileradapterfactory, jspnamemangler, object, task, throwable

The JspCompilerAdapterFactory.java source code

/*
 *  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.tools.ant.taskdefs.optional.jsp.compilers;

import org.apache.tools.ant.AntClassLoader;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.taskdefs.optional.jsp.JspNameMangler;
import org.apache.tools.ant.taskdefs.optional.jsp.Jasper41Mangler;


/**
 * Creates the necessary compiler adapter, given basic criteria.
 *
 */
public final class JspCompilerAdapterFactory {

    /** This is a singleton -- can't create instances!! */
    private JspCompilerAdapterFactory() {
    }

    /**
     * Based on the parameter passed in, this method creates the necessary
     * factory desired.
     *
     * The current mapping for compiler names are as follows:
     * <ul>
jasper = jasper compiler (the default)
     * <li>a fully quallified classname = the name of a jsp compiler
     * adapter
     * </ul>
     *
     * @param compilerType either the name of the desired compiler, or the
     * full classname of the compiler's adapter.
     * @param task a task to log through.
     * @return the compiler
     * @throws BuildException if the compiler type could not be resolved into
     * a compiler adapter.
     */
    public static JspCompilerAdapter getCompiler(String compilerType, Task task)
        throws BuildException {
        return getCompiler(compilerType, task,
                           task.getProject().createClassLoader(null));
    }

    /**
     * Based on the parameter passed in, this method creates the necessary
     * factory desired.
     *
     * The current mapping for compiler names are as follows:
     * <ul>
jasper = jasper compiler (the default)
     * <li>a fully quallified classname = the name of a jsp compiler
     * adapter
     * </ul>
     *
     * @param compilerType either the name of the desired compiler, or the
     * full classname of the compiler's adapter.
     * @param task a task to log through.
     * @param loader AntClassLoader with which the compiler should be loaded
     * @return the compiler
     * @throws BuildException if the compiler type could not be resolved into
     * a compiler adapter.
     */
    public static JspCompilerAdapter getCompiler(String compilerType, Task task,
                                                 AntClassLoader loader)
        throws BuildException {

        if (compilerType.equalsIgnoreCase("jasper")) {
            //tomcat4.0 gets the old mangler
            return new JasperC(new JspNameMangler());
        }
        if (compilerType.equalsIgnoreCase("jasper41")) {
            //tomcat4.1 gets the new one
            return new JasperC(new Jasper41Mangler());
        }
        return resolveClassName(compilerType, loader);
    }

    /**
     * Tries to resolve the given classname into a compiler adapter.
     * Throws a fit if it can't.
     *
     * @param className The fully qualified classname to be created.
     * @param classloader Classloader with which to load the class
     * @throws BuildException This is the fit that is thrown if className
     * isn't an instance of JspCompilerAdapter.
     */
    private static JspCompilerAdapter resolveClassName(String className,
                                                       AntClassLoader classloader)
        throws BuildException {
        try {
            Class c = classloader.findClass(className);
            Object o = c.newInstance();
            return (JspCompilerAdapter) o;
        } catch (ClassNotFoundException cnfe) {
            throw new BuildException(className + " can\'t be found.", cnfe);
        } catch (ClassCastException cce) {
            throw new BuildException(className + " isn\'t the classname of "
                                     + "a compiler adapter.", cce);
        } catch (Throwable t) {
            // for all other possibilities
            throw new BuildException(className + " caused an interesting "
                                     + "exception.", t);
        }
    }

}