/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package org.apache.jmeter.functions;

import java.util.Collection;

import org.apache.jmeter.samplers.SampleResult;
import org.apache.jmeter.samplers.Sampler;
import org.apache.jmeter.threads.JMeterContext;
import org.apache.jmeter.threads.JMeterContextService;
import org.apache.jmeter.threads.JMeterVariables;

/**
 * Provides common methods for all functions
 */
public abstract class AbstractFunction implements Function {

	/**
	 * @see Function#execute(SampleResult, Sampler)
	 */
	abstract public String execute(SampleResult previousResult, Sampler currentSampler) throws InvalidVariableException;

	public String execute() throws InvalidVariableException {
		JMeterContext context = JMeterContextService.getContext();
		SampleResult previousResult = context.getPreviousResult();
		Sampler currentSampler = context.getCurrentSampler();
		return execute(previousResult, currentSampler);
	}

	/**
	 * @see Function#setParameters(Collection)
     * Note: This may not be called (e.g. if no parameters are provided)
     * 
	 */
	abstract public void setParameters(Collection parameters) throws InvalidVariableException;

	/**
	 * @see Function#getReferenceKey()
	 */
	abstract public String getReferenceKey();

	protected JMeterVariables getVariables() {
		return JMeterContextService.getContext().getVariables();
	}
    
    /*
     * Utility method to check parameter counts 
     */
    protected void checkParameterCount(Collection parameters, int min, int max) 
        throws InvalidVariableException
    {
        int num = parameters.size();
        if ((num > max) || (num < min)) {
            throw new InvalidVariableException(
                    "Wrong number of parameters. Actual: "+num+
                    ". Expected: >= "+min
                    +" and <= "+max
                    );
        }
    }
}

@@ -1744,16 +1744,26 @@
 ection)%0A
+%09 * %3Cbr/%3E%0A
      * N
@@ -1776,26 +1776,25 @@
 his 
-may not be
+is always
  called 
 (e.g
@@ -1793,13 +1793,12 @@
 led 
-(e.g.
+even
  if 
@@ -1823,16 +1823,56 @@
 provided
+ %0A     * (versions of JMeter after 2.3.1
 )%0A     *
@@ -2178,16 +2178,17 @@
  %0A    /*
+*
 %0A     * 
@@ -2227,17 +2227,274 @@
 r counts
- 
+.%0A     * %0A     * @param parameters collection of parameters%0A     * @param min minimum number of parameters allowed%0A     * @param max maximum number of parameters allowed%0A     * %0A     * @throws InvalidVariableException if the number of parameters is incorrect
 %0A     */
@@ -2764,18 +2764,65 @@
     
-        %22W
+%09%09getReferenceKey() +%0A                    %22 called with w
 rong
@@ -2879,16 +2879,72 @@
         
+(%0A                    %09min==max ? %0A                    %09
 %22. Expec
@@ -2951,17 +2951,19 @@
 ted:
- %3E=
  %22+min
++%22.%22 
 %0A   
@@ -2983,23 +2983,69 @@
     
-+%22 and %3C= %22+max
+%09: %22. Expected: %3E= %22+min+%22 and %3C= %22+max%0A                    )
 %0A   

Improve parameter checking message