DefaultXmlRoundTripFileManager.java

package org.springframework.roo.addon.web.mvc.jsp.roundtrip;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.Validate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.Service;
import org.springframework.roo.process.manager.FileManager;
import org.springframework.roo.support.util.DomUtils;
import org.springframework.roo.support.util.XmlRoundTripUtils;
import org.springframework.roo.support.util.XmlUtils;
import org.w3c.dom.Document;

/**
 * Default implementation of {@link XmlRoundTripFileManager}.
 * 
 * @author James Tyrrell
 * @since 1.2.0
 */
@Component
@Service
public class DefaultXmlRoundTripFileManager implements XmlRoundTripFileManager {

  @Reference
  private FileManager fileManager;
  private final Map<String, String> fileContentsMap = new HashMap<String, String>();

  public void writeToDiskIfNecessary(final String filename, final Document proposed) {
    Validate.notNull(filename, "The file name is required");
    Validate.notNull(proposed, "The proposed document is required");
    if (fileManager.exists(filename)) {
      final String proposedContents = XmlUtils.nodeToString(proposed);
      try {
        final String contents = FileUtils.readFileToString(new File(filename)) + proposedContents;
        final String contentsSha = DigestUtils.shaHex(contents);
        final String lastContents = fileContentsMap.get(filename);
        if (lastContents != null && contentsSha.equals(lastContents)) {
          return;
        }
        fileContentsMap.put(filename, contentsSha);
      } catch (final IOException ignored) {
      }
      try {
        final Document original = XmlUtils.readXml(fileManager.getInputStream(filename));
        if (XmlRoundTripUtils.compareDocuments(original, proposed)) {
          DomUtils.removeTextNodes(original);
          final String updateContents = XmlUtils.nodeToString(original);
          fileManager.createOrUpdateTextFileIfRequired(filename, updateContents, false);
        }
      } catch (final Exception e) {
        throw new IllegalStateException("Failed to write " + filename + " : " + e.getMessage());
      }
    } else {
      final String contents = XmlUtils.nodeToString(proposed);
      final String contentsSha = DigestUtils.shaHex(contents + contents);
      fileContentsMap.put(filename, contentsSha);
      fileManager.createOrUpdateTextFileIfRequired(filename, contents, false);
    }
  }
}