com.maddyhome.idea.copyright.pattern.VelocityHelper.java Source code

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Here is the source code for com.maddyhome.idea.copyright.pattern.VelocityHelper.java

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/*
 * Copyright 2000-2009 JetBrains s.r.o.
 *
 * 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 com.maddyhome.idea.copyright.pattern;

import com.intellij.openapi.application.PathManager;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.psi.PsiFile;
import com.maddyhome.idea.copyright.CopyrightManager;
import org.apache.commons.collections.ExtendedProperties;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.log.SimpleLog4JLogSystem;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.io.StringWriter;

public class VelocityHelper {
    private static VelocityEngine instance;

    private VelocityHelper() {
    }

    @NotNull
    public static String evaluate(@Nullable PsiFile file, @Nullable Project project, @Nullable Module module,
            @NotNull String template) throws Exception {
        VelocityEngine engine = getEngine();

        VelocityContext vc = new VelocityContext();
        vc.put("today", new DateInfo());
        if (file != null)
            vc.put("file", new FileInfo(file));
        if (project != null)
            vc.put("project", new ProjectInfo(project));
        if (module != null)
            vc.put("module", new ModuleInfo(module));
        vc.put("username", System.getProperty("user.name"));

        StringWriter sw = new StringWriter();
        boolean stripLineBreak = false;
        if (template.endsWith("$")) {
            template += getVelocitySuffix();
            stripLineBreak = true;
        }
        engine.evaluate(vc, sw, CopyrightManager.class.getName(), template);
        final String result = sw.getBuffer().toString();
        return stripLineBreak ? StringUtil.trimEnd(result, getVelocitySuffix()) : result;
    }

    private static String getVelocitySuffix() {
        return "\n";
    }

    private static synchronized VelocityEngine getEngine() {
        if (instance == null) {
            try {
                VelocityEngine engine = new VelocityEngine();
                ExtendedProperties extendedProperties = new ExtendedProperties();

                extendedProperties.addProperty(RuntimeConstants.RESOURCE_LOADER, "file");
                extendedProperties.addProperty(RuntimeConstants.PARSER_POOL_SIZE, "1");

                extendedProperties.addProperty("file.resource.loader.class",
                        "org.apache.velocity.runtime.resource.loader.FileResourceLoader");
                extendedProperties.addProperty("file.resource.loader.path",
                        PathManager.getPluginsPath() + "/Copyright/resources");

                extendedProperties.addProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS,
                        SimpleLog4JLogSystem.class.getName());
                extendedProperties.addProperty("runtime.log.logsystem.log4j.category",
                        CopyrightManager.class.getName());

                engine.setExtendedProperties(extendedProperties);
                engine.init();

                instance = engine;
            } catch (Exception ignored) {
            }
        }

        return instance;
    }
}