org.opennaas.extensions.router.junos.commandsets.velocity.VelocityEngine.java Source code

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Here is the source code for org.opennaas.extensions.router.junos.commandsets.velocity.VelocityEngine.java

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package org.opennaas.extensions.router.junos.commandsets.velocity;

/*
 * #%L
 * OpenNaaS :: Router :: Junos ActionSet
 * %%
 * Copyright (C) 2007 - 2014 Fundaci Privada i2CAT, Internet i Innovaci a Catalunya
 * %%
 * 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.
 * #L%
 */

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;

public class VelocityEngine {

    private final Map<String, Object> extraParams = new HashMap<String, Object>();

    public static final String PARAM_CONSTANT = "param";

    Log log = LogFactory.getLog(VelocityEngine.class);

    private static String VELOCITY_PROPS = "/velocity.properties";

    private String template;

    private Object param;

    private void init() throws Exception {
        InputStream velocityPropFile = getClass().getResourceAsStream(VELOCITY_PROPS);

        if (velocityPropFile == null)
            throw new ResourceNotFoundException("Cannot load: " + VELOCITY_PROPS);

        Properties prop = new Properties();
        prop.load(velocityPropFile);

        Velocity.init(prop);

    }

    public String mergeTemplate() throws ResourceNotFoundException, ParseErrorException, Exception {
        init();
        String currentPath = (new File(".")).getCanonicalPath();
        log.info("Current directory to get template: " + currentPath);

        Template tpl = Velocity.getTemplate(template);

        VelocityContext ctx = new VelocityContext();

        // //TODO FIX PROBLEMS TO PARAMS IN NULL
        ctx.put(PARAM_CONSTANT, param);

        for (String key : extraParams.keySet())
            ctx.put(key, extraParams.get(key));

        Writer writer = new StringWriter();

        tpl.merge(ctx, writer);

        return writer.toString();
    }

    public void addExtraParam(String name, Object newParam) {
        this.extraParams.put(name, newParam);
    }

    public void setParam(Object param) {
        this.param = param;
    }

    public String getTemplate() {
        return template;
    }

    public void setTemplate(String template) {
        this.template = template;
    }

    /*
     * It must exist other method to implements this method to get resources It was used to get the velocity template from a jar. In old versions, it
     * gave troubles to use
     */
    @Deprecated
    private void addJarProperties(Properties prop) {
        Properties oldProps = (Properties) prop.clone();
        prop.setProperty("resource.loader", "jar");
        prop.setProperty("jar.resource.loader.class",
                "org.apache.velocity.runtime.resource.loader.JarResourceLoader");
        prop.setProperty("jar.resource.loader.cache", "true");
        String absolutPath = "";
        try {
            absolutPath = "jar:file:" + (new File(".")).getCanonicalPath();
        } catch (IOException e) {
            log.error("It was impossible to get the canonical path");
            // Restore propeties file
            prop = oldProps;
            return;
        }
        log.info("absoluthPath=" + absolutPath);
        prop.setProperty("jar.resource.loader.path",
                absolutPath + "/bundles/net.i2cat.mantychore.commandsets.junos_1.0.0.SNAPSHOT.jar");
        // where there are templates
        prop.setProperty("template.root", "VM_files");

    }

}