ParseDateTag.java :  » EJB-Server » GlassFish » appserv-jstl » org » apache » taglibs » standard » tag » el » fmt » Java Open Source

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package org.apache.taglibs.standard.tag.el.fmt;

import java.util.Locale;

import javax.servlet.jsp.JspException;

import org.apache.taglibs.standard.lang.support.ExpressionEvaluatorManager;
import org.apache.taglibs.standard.tag.common.fmt.ParseDateSupport;
import org.apache.taglibs.standard.tag.common.fmt.SetLocaleSupport;

/**
 * <p>A handler for &lt;parseDate&gt; that accepts attributes as Strings
 * and evaluates them as expressions at runtime.</p>
 *
 * @author Jan Luehe
 */

public class ParseDateTag extends ParseDateSupport {

    //*********************************************************************
    // 'Private' state (implementation details)

    private String value_;                       // stores EL-based property
    private String type_;                        // stores EL-based property
    private String dateStyle_;             // stores EL-based property
    private String timeStyle_;             // stores EL-based property
    private String pattern_;             // stores EL-based property
    private String timeZone_;             // stores EL-based property
    private String parseLocale_;           // stores EL-based property


    //*********************************************************************
    // Constructor

    /**
     * Constructs a new ParseDateTag.  As with TagSupport, subclasses
     * should not provide other constructors and are expected to call
     * the superclass constructor
     */
    public ParseDateTag() {
        super();
        init();
    }


    //*********************************************************************
    // Tag logic

    // evaluates expression and chains to parent
    public int doStartTag() throws JspException {

        // evaluate any expressions we were passed, once per invocation
        evaluateExpressions();

  // chain to the parent implementation
  return super.doStartTag();
    }

    // Releases any resources we may have (or inherit)
    public void release() {
        super.release();
        init();
    }


    //*********************************************************************
    // Accessor methods

    // for EL-based attribute
    public void setValue(String value_) {
        this.value_ = value_;
  this.valueSpecified = true;
    }

    // for EL-based attribute
    public void setType(String type_) {
        this.type_ = type_;
    }

    // for EL-based attribute
    public void setDateStyle(String dateStyle_) {
        this.dateStyle_ = dateStyle_;
    }

    // for EL-based attribute
    public void setTimeStyle(String timeStyle_) {
        this.timeStyle_ = timeStyle_;
    }

    // for EL-based attribute
    public void setPattern(String pattern_) {
        this.pattern_ = pattern_;
    }

    // for EL-based attribute
    public void setTimeZone(String timeZone_) {
        this.timeZone_ = timeZone_;
    }

    // for EL-based attribute
    public void setParseLocale(String parseLocale_) {
        this.parseLocale_ = parseLocale_;
    }


    //*********************************************************************
    // Private (utility) methods

    // (re)initializes state (during release() or construction)
    private void init() {
        // null implies "no expression"
  value_ = type_ = dateStyle_ = timeStyle_ = pattern_ = timeZone_ = null;
  parseLocale_ = null;
    }

    // Evaluates expressions as necessary
    private void evaluateExpressions() throws JspException {
        /* 
         * Note: we don't check for type mismatches here; we assume
         * the expression evaluator will return the expected type
         * (by virtue of knowledge we give it about what that type is).
         * A ClassCastException here is truly unexpected, so we let it
         * propagate up.
         */

  // 'value' attribute
  if (value_ != null) {
      value = (String) ExpressionEvaluatorManager.evaluate(
          "value", value_, String.class, this, pageContext);
  }

  // 'type' attribute
  if (type_ != null) {
      type = (String) ExpressionEvaluatorManager.evaluate(
          "type", type_, String.class, this, pageContext);
  }

  // 'dateStyle' attribute
  if (dateStyle_ != null) {
      dateStyle = (String) ExpressionEvaluatorManager.evaluate(
          "dateStyle", dateStyle_, String.class, this, pageContext);
  }

  // 'timeStyle' attribute
  if (timeStyle_ != null) {
      timeStyle = (String) ExpressionEvaluatorManager.evaluate(
          "timeStyle", timeStyle_, String.class, this, pageContext);
  }

  // 'pattern' attribute
  if (pattern_ != null) {
      pattern = (String) ExpressionEvaluatorManager.evaluate(
          "pattern", pattern_, String.class, this, pageContext);
  }

  // 'timeZone' attribute
  if (timeZone_ != null) {
      timeZone = ExpressionEvaluatorManager.evaluate(
          "timeZone", timeZone_, Object.class, this, pageContext);
  }

  // 'parseLocale' attribute
  if (parseLocale_ != null) {
      Object obj = ExpressionEvaluatorManager.evaluate(
          "parseLocale", parseLocale_, Object.class, this, pageContext);
      if (obj != null) {
    if (obj instanceof Locale) {
        parseLocale = (Locale) obj;
    } else {
        String localeStr = (String) obj;
        if (!"".equals(localeStr)) {
      parseLocale = SetLocaleSupport.parseLocale(localeStr);
        }
    }
      }
  }
    }
}