/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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 groovy.text;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.net.URL;

import org.codehaus.groovy.control.CompilationFailedException;
import org.codehaus.groovy.runtime.DefaultGroovyMethodsSupport;

/**
 * Represents an API to any template engine which is basically a factory of Template instances from a given text input.
 * 
 * @author sam
 */
public abstract class TemplateEngine {
    public abstract Template createTemplate(Reader reader) throws CompilationFailedException, ClassNotFoundException, IOException;
    
    public Template createTemplate(String templateText) throws CompilationFailedException, ClassNotFoundException, IOException {
        return createTemplate(new StringReader(templateText));
    }
    
    public Template createTemplate(File file) throws CompilationFailedException, ClassNotFoundException, IOException {
        Reader reader = new FileReader(file);
        try {
            return createTemplate(reader);
        } finally {
            DefaultGroovyMethodsSupport.closeWithWarning(reader);
        }
    }

    public Template createTemplate(URL url) throws CompilationFailedException, ClassNotFoundException, IOException {
        Reader reader = new InputStreamReader(url.openStream());
        try {
            return createTemplate(reader);
        } finally {
            DefaultGroovyMethodsSupport.closeWithWarning(reader);
        }
    }
}