com.devonfw.cobigen.tempeng.freemarker.NioFileSystemTemplateLoader Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of tempeng-freemarker Show documentation

CobiGen - FreeMarker Template Engine

The newest version!

package com.devonfw.cobigen.tempeng.freemarker;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.devonfw.cobigen.api.exception.CobiGenRuntimeException;
import com.devonfw.cobigen.tempeng.freemarker.constant.FreemarkerMetadata;

import freemarker.cache.TemplateLoader;

/**
 * Generic {@link TemplateLoader} for {@link FileSystem}
 */
public class NioFileSystemTemplateLoader implements TemplateLoader {

  /**
   * SLF4J Logger instance.
   */
  private static final Logger LOG = LoggerFactory.getLogger(NioFileSystemTemplateLoader.class);

  /**
   * Root path to resolve templates from
   */
  private Path templatesRoot;

  @Override
  public Object findTemplateSource(String name) throws IOException {

    if (this.templatesRoot == null) {
      throw new CobiGenRuntimeException(
          "No template root has been defined. This is a bug. (FreeMarker v" + FreemarkerMetadata.VERSION + ")");
    }
    return this.templatesRoot.resolve(name);
  }

  @Override
  public long getLastModified(Object templateSource) {

    BasicFileAttributes attrs;
    Path templatePath = (Path) templateSource;
    try {
      attrs = Files.readAttributes(templatePath, BasicFileAttributes.class);
      return attrs.lastModifiedTime().toMillis();
    } catch (IOException e) {
      LOG.warn("An error occured while resolving the last modified file attribute of path '{}'. (FreeMarker v{})",
          templatePath.toAbsolutePath().toString(), FreemarkerMetadata.VERSION, e);
    }
    return 0;
  }

  @Override
  public Reader getReader(Object templateSource, String encoding) throws IOException {

    // need to keep this reader open as of method contract
    return new InputStreamReader(Files.newInputStream((Path) templateSource), encoding);
  }

  @Override
  public void closeTemplateSource(Object templateSource) throws IOException {

    // do nothing (referring to FreeMarkers FileTemlpateLoader.class implementation)
  }

  /**
   * Sets the field 'templateRoot'.
   *
   * @param templateRoot new value of templateRoot
   */
  public void setTemplateRoot(Path templateRoot) {

    this.templatesRoot = templateRoot;
  }

}