Examples of org.apache.commons.el.ExpressionEvaluatorImpl

org.apache.commons.el.ExpressionEvaluatorImpl

This is the main class for evaluating expression Strings. An expression String is a String that may contain expressions of the form ${...}. Multiple expressions may appear in the same expression String. In such a case, the expression String's value is computed by concatenating the String values of those evaluated expressions and any intervening non-expression text, then converting the resulting String to the expected type using the PropertyEditor mechanism.
In the special case where the expression String is a single expression, the value of the expression String is determined by evaluating the expression, without any intervening conversion to a String.
The evaluator maintains a cache mapping expression Strings to their parsed results. For expression Strings containing no expression elements, it maintains a cache mapping ExpectedType/ExpressionString to parsed value, so that static expression Strings won't have to go through a conversion step every time they are used. All instances of the evaluator share the same cache. The cache may be bypassed by setting a flag on the evaluator's constructor.
The evaluator must be passed a VariableResolver in its constructor. The VariableResolver is used to resolve variable names encountered in expressions, and can also be used to implement "implicit objects" that are always present in the namespace. Different applications will have different policies for variable lookups and implicit objects - these differences can be encapsulated in the VariableResolver passed to the evaluator's constructor.
Most VariableResolvers will need to perform their resolution against some context. For example, a JSP environment needs a PageContext to resolve variables. The evaluate() method takes a generic Object context which is eventually passed to the VariableResolver - the VariableResolver is responsible for casting the context to the proper type.
Once an evaluator instance has been constructed, it may be used multiple times, and may be used by multiple simultaneous Threads. In other words, an evaluator instance is well-suited for use as a singleton. @author Nathan Abramson - Art Technology Group @author Shawn Bayern @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $


    /**
     * Constructor.
     */
    public ELEvaluator() {
        ee = new ExpressionEvaluatorImpl();
    }

View Full Code Here

     *
     * @param fnMapper The function mapper for this Evaluator.
     * @see javax.servlet.jsp.el.FunctionMapper
     */
    public ELEvaluator(final FunctionMapper fnMapper) {
        ee = new ExpressionEvaluatorImpl();
        this.fnMapper = fnMapper;
    }

View Full Code Here

     *
     * @return Log The log being used.
     */
    private ExpressionEvaluator getEvaluator() {
        if (ee == null) {
            ee = new ExpressionEvaluatorImpl();
        }
        return ee;
    }

View Full Code Here

   * @throws ELException 
   */
  public Object evaluateExpression(String expression, Class expectedClass,
      Map options) throws ELException {
    expression = JSFELParserHelper.toJspElExpression(expression);
    ExpressionEvaluatorImpl evaluator = new ExpressionEvaluatorImpl();
    FunctionMapper mapper = new EmptyFunctionMapper();


    return evaluator.evaluate(expression, expectedClass, resolver, mapper);
  }

View Full Code Here

        this.session = new MockHttpSession();
        this.pageScopeAttributes = new HashMap();
        this.applicationScopeAttributes = new HashMap();
        this.servletContext = new MockServletContext();
        this.servletConfig = new MockServletConfig(servletContext);
        this.expressionEvaluator = new ExpressionEvaluatorImpl();
    }

View Full Code Here

        return ee.evaluate(expression, expectedType, getVariableResolver(actionForm, request, servletContext), null);
    }


    private static final ExpressionEvaluator getExpressionEvaluator()
    {
        return new ExpressionEvaluatorImpl();
    }

View Full Code Here


    /**
     * Constructor.
     */
    public ELEvaluator() {
        ee = new ExpressionEvaluatorImpl();
    }

View Full Code Here

     *
     * @param fnMapper The function mapper for this Evaluator.
     * @see javax.servlet.jsp.el.FunctionMapper
     */
    public ELEvaluator(final FunctionMapper fnMapper) {
        ee = new ExpressionEvaluatorImpl();
        this.fnMapper = fnMapper;
    }

View Full Code Here

   *
   * @param data DOCUMENT ME!
   * @param handler DOCUMENT ME!
   */
  public void handle(String data, ContentHandler handler) {
    ExpressionEvaluator evaluator = new ExpressionEvaluatorImpl();
    Object value;


    try {
      value = evaluator.evaluate(data, Object.class, resolver, mapper);


      if (value != null) {
        char[] result = value.toString().toCharArray();
        handler.characters(result, 0, result.length);
      } else {

View Full Code Here

        return ee.evaluate(expression, expectedType, getVariableResolver(actionForm, request, servletContext), null);
    }


    private static final ExpressionEvaluator getExpressionEvaluator()
    {
        return new ExpressionEvaluatorImpl();
    }

View Full Code Here

0 1

TOP

Related Classes of org.apache.commons.el.ExpressionEvaluatorImpl

com.agilejava.docbkx.maven.ExpressionHandler

net.sf.jpluck.apps.jpluckx.ui.DocumentDialog

net.sf.jpluck.util.el.TestingTool$Evaluate

net.sf.jsptest.compiler.jsp20.mock.MockPageContext

org.apache.beehive.netui.pageflow.internal.InternalExpressionUtils

org.apache.commons.el.parser.ELParser

org.apache.commons.el.parser.Token

org.apache.commons.scxml.env.jsp.ELEvaluator

org.apache.taglibs.rdc.dm.DMUtils

org.eclipse.jst.pagedesigner.preview.PageExpressionContext

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.