Package org.pentaho.reporting.engine.classic.core.filter

Source Code of org.pentaho.reporting.engine.classic.core.filter.MessageFormatSupport$MessageCompiler

/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2009 Object Refinery Ltd, Pentaho Corporation and Contributors..  All rights reserved.
*/

package org.pentaho.reporting.engine.classic.core.filter;

import java.io.Serializable;
import java.io.Reader;
import java.io.StringWriter;
import java.io.IOException;
import java.sql.Clob;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.Locale;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.DataRow;
import org.pentaho.reporting.engine.classic.core.filter.types.ElementTypeUtils;
import org.pentaho.reporting.engine.classic.core.util.PropertyLookupParser;
import org.pentaho.reporting.libraries.base.util.CSVTokenizer;
import org.pentaho.reporting.libraries.base.util.ObjectUtilities;
import org.pentaho.reporting.libraries.base.util.IOUtils;
import org.pentaho.reporting.libraries.formatting.FastMessageFormat;

/**
* The message format support class helps to translate named references to fields in a message format string into
* numeric index positions. With the help of this mapping, we can use a standard Java MessageFormat object to reference
* fields by their name instead of an arbitrary index position.
* <p/>
* A field is referenced by the pattern "$(fieldname)". For additional formatting, all MessageFormat format options are
* available using the format "$(fieldname, &lt;message option&gt;)". To format a date field with the default short date
* format, one would use the pattern $(datefield,date,short).
*
* @author Thomas Morgner
*/
public class MessageFormatSupport implements Serializable, Cloneable
{
  private static final Log logger = LogFactory.getLog(MessageFormatSupport.class);
  private static final String[] EMPTY_FIELDS = new String[0];

  /**
   * The message compiler maps all named references into numeric references.
   */
  protected static class MessageCompiler extends PropertyLookupParser
  {
    /**
     * The list of fields that have been encountered during the compile process.
     */
    private ArrayList fields;

    /**
     * Default Constructor.
     */
    protected MessageCompiler()
    {
      this.fields = new ArrayList();
      setMarkerChar('$');
      setOpeningBraceChar('(');
      setClosingBraceChar(')');
    }

    /**
     * Looks up the property with the given name. This replaces the name with the current index position.
     *
     * @param name the name of the property to look up.
     * @return the translated value.
     */
    protected String lookupVariable(final String name)
    {
      final CSVTokenizer tokenizer = new CSVTokenizer(name, false);
      if (tokenizer.hasMoreTokens() == false)
      {
        return null;
      }
      final String varName = tokenizer.nextToken();

      final StringBuffer b = new StringBuffer(name.length());
      b.append('{');
      b.append(String.valueOf(fields.size()));
      while (tokenizer.hasMoreTokens())
      {
        b.append(',');
        b.append(tokenizer.nextToken());
      }
      b.append('}');
      final String formatString = b.toString();
      fields.add(varName);
      return formatString;
    }

    /**
     * Returns the collected fields as string-array. The order of the array contents matches the order of the
     * index-position references in the translated message format.
     *
     * @return the fields as array.
     */
    public String[] getFields()
    {
      return (String[]) fields.toArray(new String[fields.size()]);
    }
  }

  /**
   * The fields that have been collected during the compile process. The array also acts as mapping of index positions
   * to field names.
   */
  private String[] fields;
  /**
   * The message-format object that is used to format the text.
   */
  private FastMessageFormat format;
  /**
   * The original format string.
   */
  private String formatString;
  /**
   * The translated message format string. All named references have been resolved to numeric index positions.
   */
  private String compiledFormat;
  /**
   * The replacement text that is used if one of the referenced message parameters is null.
   */
  private String nullString;

  /**
   * The current locale of the message format.
   */
  private transient Locale locale;
  /**
   * An internal list of all parameters.
   */
  private transient Object[] parameters;
  /**
   * An internal list of all parameters. This list is used to compare the current parameters with the cached ones.
   */
  private transient Object[] oldParameters;
  /**
   * The cached formatted string value.
   */
  private String cachedValue;

  /**
   * Default Constructor.
   */
  public MessageFormatSupport()
  {
  }

  /**
   * Returns the original format string that is used to format the fields. This format string contains named
   * references.
   *
   * @return the format string.
   */
  public String getFormatString()
  {
    return formatString;
  }

  /**
   * Updates the named format string and compiles a new field list and message-format string.
   *
   * @param formatString the format string.
   */
  public void setFormatString(final String formatString)
  {
    if (formatString == null)
    {
      throw new NullPointerException("Format must not be null");
    }

    if (ObjectUtilities.equal(formatString, this.formatString))
    {
      return;
    }

    final MessageCompiler compiler = new MessageCompiler();
    this.compiledFormat = compiler.translateAndLookup(formatString);
    this.fields = compiler.getFields();

    if (fields.length > 0)
    {
      this.format = new FastMessageFormat(this.compiledFormat);
      if (nullString != null)
      {
        this.format.setNullString(nullString);
      }
    }
    else
    {
      this.format = null;
    }
    this.formatString = formatString;
    this.parameters = null;
    this.oldParameters = null;
    this.cachedValue = null;
  }

  /**
   * Formats the message using the fields from the given data-row as values for the parameters.
   *
   * @param dataRow the data row.
   * @return the formated message.
   */
  public String performFormat(final DataRow dataRow)
  {
    if (fields == null)
    {
      return null;
    }
    if (fields.length == 0)
    {
      return formatString;
    }

    if (parameters == null)
    {
      parameters = new Object[fields.length];
    }
    final int parameterCount = parameters.length;
    if (oldParameters == null)
    {
      oldParameters = new Object[fields.length];
    }
    else
    {
      System.arraycopy(parameters, 0, oldParameters, 0, parameterCount);
    }

    for (int i = 0; i < fields.length; i++)
    {
      final String field = fields[i];
      final Object o = dataRow.get(field);
      if (o instanceof Number)
      {
        parameters[i] = o;
      }
      else if (o instanceof Date)
      {
        parameters[i] = o;
      }
      else
      {
        parameters[i] = ElementTypeUtils.toString(o);
      }
    }

    if (cachedValue != null && Arrays.equals(parameters, oldParameters))
    {
      return cachedValue;
    }

    cachedValue = format.format(parameters);
    return cachedValue;
  }

  /**
   * Returns the compiled message format string.
   *
   * @return the compiled message format string.
   */
  public String getCompiledFormat()
  {
    return compiledFormat;
  }

  /**
   * Returns the locale that is used to format the messages.
   *
   * @return the locale in the message format.
   */
  public Locale getLocale()
  {
    return format.getLocale();
  }

  /**
   * Updates the locale that is used to format the messages.
   *
   * @param locale the locale in the message format.
   */
  public void setLocale(final Locale locale)
  {
    if (ObjectUtilities.equal(locale, this.locale))
    {
      return;
    }
    this.locale = locale;
    if (format != null)
    {
      this.format.setLocale(locale);
    }

    this.parameters = null;

    this.oldParameters = null;
    this.cachedValue = null;
  }

  /**
   * Returns the replacement text that is used if one of the referenced message parameters is null.
   *
   * @return the replacement text for null-values.
   */
  public String getNullString()
  {
    return nullString;
  }

  /**
   * Defines the replacement text that is used if one of the referenced message parameters is null.
   *
   * @param nullString the replacement text for null-values.
   */
  public void setNullString(final String nullString)
  {
    if (ObjectUtilities.equal(nullString, this.nullString) == false)
    {
      this.nullString = nullString;
      if (format != null)
      {
        this.format.setNullString(nullString);
      }

      this.oldParameters = null;
      this.cachedValue = null;
    }
  }

  public String[] getFields()
  {
    if (fields == null)
    {
      return EMPTY_FIELDS;
    }
    return (String[]) fields.clone();
  }

  /**
   * Creates a copy of this message format support object.
   *
   * @return the copy.
   * @throws CloneNotSupportedException if an error occured.
   */
  public Object clone()
      throws CloneNotSupportedException
  {
    final MessageFormatSupport support = (MessageFormatSupport) super.clone();
    if (format != null)
    {
      support.format = (FastMessageFormat) format.clone();
    }
    if (parameters != null)
    {
      support.parameters = (Object[]) parameters.clone();
    }

    this.oldParameters = null;
    this.cachedValue = null;
    return support;
  }
}
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