VelocityTemplate.java

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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.jboss.seam.mail.templating.velocity;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;
import java.util.Map;

import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.runtime.RuntimeConstants;
import org.jboss.seam.mail.core.TemplatingException;
import org.jboss.seam.mail.templating.TemplateProvider;

/**
 * @author Cody Lerum
 */
public class VelocityTemplate implements TemplateProvider {
    private VelocityEngine velocityEngine;
    private VelocityContext velocityContext;
    private CDIVelocityContext cdiContext;
    private InputStream inputStream;

    public VelocityTemplate(InputStream inputStream) {
        velocityEngine = new VelocityEngine();
        velocityEngine
                .setProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS, "org.apache.velocity.runtime.log.NullLogChute");
        this.inputStream = inputStream;
    }

    public VelocityTemplate(InputStream inputStream, CDIVelocityContext cdiContext) {
        this(inputStream);
        this.cdiContext = cdiContext;
    }

    public VelocityTemplate(String string) {
        this(new ByteArrayInputStream(string.getBytes()));
    }

    public VelocityTemplate(String string, CDIVelocityContext cdiContext) {
        this(new ByteArrayInputStream(string.getBytes()), cdiContext);
    }

    public VelocityTemplate(File file) throws FileNotFoundException {
        this(new FileInputStream(file));
    }

    public VelocityTemplate(File file, CDIVelocityContext cdiContext) throws FileNotFoundException {
        this(new FileInputStream(file), cdiContext);
    }

    public String merge(Map<String, Object> context) {
        StringWriter writer = new StringWriter();

        if (cdiContext != null) {
            velocityContext = new VelocityContext(context, cdiContext);
        } else {
            velocityContext = new VelocityContext(context);
        }

        try {
            velocityEngine.evaluate(velocityContext, writer, "mailGenerated", new InputStreamReader(inputStream));
        } catch (ResourceNotFoundException e) {
            throw new TemplatingException("Unable to find template", e);
        } catch (ParseErrorException e) {
            throw new TemplatingException("Unable to find template", e);
        } catch (MethodInvocationException e) {
            throw new TemplatingException("Error processing method referenced in context", e);
        }

        return writer.toString();
    }
}