/* $Id: CallMethodRule.java 992060 2010-09-02 19:09:47Z simonetripodi $
 *
 * 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.commons.digester;


import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.MethodUtils;
import org.xml.sax.Attributes;


Rule implementation that calls a method on an object on the stack
(normally the top/parent object), passing arguments collected from 
subsequent CallParamRule rules or from the body of this
element. 
By using CallMethodRule(String methodName) a method call can be made to a method which accepts no arguments.
Incompatible method parameter types are converted 
using org.apache.commons.beanutils.ConvertUtils.

This rule now uses MethodUtils.invokeMethod by default. This increases the kinds of methods successfully and allows primitives to be matched by passing in wrapper classes. There are rare cases when MethodUtils.invokeExactMethod (the old default) is required. This method is much stricter in it's reflection. Setting the UseExactMatch to true reverts to the use of this 
method.
Note that the target method is invoked when the  end of
the tag the CallMethodRule fired on is encountered, not when the
last parameter becomes available. This implies that rules which fire on
tags nested within the one associated with the CallMethodRule will 
fire before the CallMethodRule invokes the target method. This behaviour is
not configurable. 
Note also that if a CallMethodRule is expecting exactly one parameter
and that parameter is not available (eg CallParamRule is used with an
attribute name but the attribute does not exist) then the method will
not be invoked. If a CallMethodRule is expecting more than one parameter,
then it is always invoked, regardless of whether the parameters were
available or not; missing parameters are converted to the appropriate target
type by calling ConvertUtils.convert. Note that the default ConvertUtils
converters for the String type returns a null when passed a null, meaning
that CallMethodRule will passed null for all String parameters for which
there is no parameter info available from the XML. However parameters of
type Float and Integer will be passed a real object containing a zero value
as that is the output of the default ConvertUtils converters for those
types when passed a null. You can register custom converters to change
this behaviour; see the beautils library documentation for more info.
Note that when a constructor is used with paramCount=0, indicating that
the body of the element is to be passed to the target method, an empty 
element will cause an empty string to be passed to the target method,
not null. And if automatic type conversion is being applied (ie if the 
target function takes something other than a string as a parameter) then 
the conversion will fail if the converter class does not accept an empty 
string as valid input.
CallMethodRule has a design flaw which can cause it to fail under
certain rule configurations. All CallMethodRule instances share a single
parameter stack, and all CallParamRule instances simply store their data
into the parameter-info structure that is on the top of the stack. This
means that two CallMethodRule instances cannot be associated with the
same pattern without getting scrambled parameter data. This same issue
also applies when a CallMethodRule matches some element X, a different 
CallMethodRule matches a child element Y and some of the CallParamRules 
associated with the first CallMethodRule match element Y or one of its 
child elements. This issue has been present since the very first release
of Digester. Note, however, that this configuration of CallMethodRule
instances is not commonly required.
/**
 * <p>Rule implementation that calls a method on an object on the stack
 * (normally the top/parent object), passing arguments collected from 
 * subsequent <code>CallParamRule</code> rules or from the body of this
 * element. </p>
 *
 * <p>By using {@link #CallMethodRule(String methodName)} 
 * a method call can be made to a method which accepts no
 * arguments.</p>
 *
 * <p>Incompatible method parameter types are converted 
 * using <code>org.apache.commons.beanutils.ConvertUtils</code>.
 * </p>
 *
 * <p>This rule now uses {@link MethodUtils#invokeMethod} by default.
 * This increases the kinds of methods successfully and allows primitives
 * to be matched by passing in wrapper classes.
 * There are rare cases when {@link MethodUtils#invokeExactMethod} 
 * (the old default) is required.
 * This method is much stricter in it's reflection.
 * Setting the <code>UseExactMatch</code> to true reverts to the use of this 
 * method.</p>
 *
 * <p>Note that the target method is invoked when the  <i>end</i> of
 * the tag the CallMethodRule fired on is encountered, <i>not</i> when the
 * last parameter becomes available. This implies that rules which fire on
 * tags nested within the one associated with the CallMethodRule will 
 * fire before the CallMethodRule invokes the target method. This behaviour is
 * not configurable. </p>
 *
 * <p>Note also that if a CallMethodRule is expecting exactly one parameter
 * and that parameter is not available (eg CallParamRule is used with an
 * attribute name but the attribute does not exist) then the method will
 * not be invoked. If a CallMethodRule is expecting more than one parameter,
 * then it is always invoked, regardless of whether the parameters were
 * available or not; missing parameters are converted to the appropriate target
 * type by calling ConvertUtils.convert. Note that the default ConvertUtils
 * converters for the String type returns a null when passed a null, meaning
 * that CallMethodRule will passed null for all String parameters for which
 * there is no parameter info available from the XML. However parameters of
 * type Float and Integer will be passed a real object containing a zero value
 * as that is the output of the default ConvertUtils converters for those
 * types when passed a null. You can register custom converters to change
 * this behaviour; see the beautils library documentation for more info.</p>
 *
 * <p>Note that when a constructor is used with paramCount=0, indicating that
 * the body of the element is to be passed to the target method, an empty 
 * element will cause an <i>empty string</i> to be passed to the target method,
 * not null. And if automatic type conversion is being applied (ie if the 
 * target function takes something other than a string as a parameter) then 
 * the conversion will fail if the converter class does not accept an empty 
 * string as valid input.</p>
 * 
 * <p>CallMethodRule has a design flaw which can cause it to fail under
 * certain rule configurations. All CallMethodRule instances share a single
 * parameter stack, and all CallParamRule instances simply store their data
 * into the parameter-info structure that is on the top of the stack. This
 * means that two CallMethodRule instances cannot be associated with the
 * same pattern without getting scrambled parameter data. This same issue
 * also applies when a CallMethodRule matches some element X, a different 
 * CallMethodRule matches a child element Y and some of the CallParamRules 
 * associated with the first CallMethodRule match element Y or one of its 
 * child elements. This issue has been present since the very first release
 * of Digester. Note, however, that this configuration of CallMethodRule
 * instances is not commonly required.</p>
 */

public class CallMethodRule extends Rule {

    // ----------------------------------------------------------- Constructors

    
Construct a "call method" rule with the specified method name.  The
parameter types (if any) default to java.lang.String.
Params:
digester – The associated Digester
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of this element.
Deprecated:
The digester instance is now set in the Digester.addRule method. Use CallMethodRule(String methodName, int paramCount) instead./**
     * Construct a "call method" rule with the specified method name.  The
     * parameter types (if any) default to java.lang.String.
     *
     * @param digester The associated Digester
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of this element.
     *
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #CallMethodRule(String methodName,int paramCount)} instead.
     */
    @Deprecated
    public CallMethodRule(Digester digester, String methodName,
                          int paramCount) {

        this(methodName, paramCount);

    }


    
Construct a "call method" rule with the specified method name.
Params:
digester – The associated Digester
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java class names of the arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean
 for a boolean parameter)
Deprecated:
The digester instance is now set in the Digester.addRule method. Use CallMethodRule(String methodName, int paramCount, String[] paramTypes) instead./**
     * Construct a "call method" rule with the specified method name.
     *
     * @param digester The associated Digester
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java class names of the arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean</code>
     *  for a <code>boolean</code> parameter)
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #CallMethodRule(String methodName,int paramCount, String [] paramTypes)} instead.
     */
    @Deprecated
    public CallMethodRule(Digester digester, String methodName,
                          int paramCount, String paramTypes[]) {

        this(methodName, paramCount, paramTypes);

    }


    
Construct a "call method" rule with the specified method name.
Params:
digester – The associated Digester
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java classes that represent the
 parameter types of the method arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean.TYPE
 for a boolean parameter)
Deprecated:
The digester instance is now set in the Digester.addRule method. Use CallMethodRule(String methodName, int paramCount, Class<?>[] paramTypes) instead./**
     * Construct a "call method" rule with the specified method name.
     *
     * @param digester The associated Digester
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java classes that represent the
     *  parameter types of the method arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean.TYPE</code>
     *  for a <code>boolean</code> parameter)
     *
     * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 
     * Use {@link #CallMethodRule(String methodName,int paramCount, Class [] paramTypes)} instead.
     */
    @Deprecated
    public CallMethodRule(Digester digester, String methodName,
                          int paramCount, Class<?> paramTypes[]) {

        this(methodName, paramCount, paramTypes);
    }


    
Construct a "call method" rule with the specified method name.  The
parameter types (if any) default to java.lang.String.
Params:
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of this element./**
     * Construct a "call method" rule with the specified method name.  The
     * parameter types (if any) default to java.lang.String.
     *
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of this element.
     */
    public CallMethodRule(String methodName,
                          int paramCount) {
        this(0, methodName, paramCount);
    }

    
Construct a "call method" rule with the specified method name.  The
parameter types (if any) default to java.lang.String.
Params:
targetOffset – location of the target object. Positive numbers are
relative to the top of the digester object stack. Negative numbers 
are relative to the bottom of the stack. Zero implies the top
object on the stack.
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of this element./**
     * Construct a "call method" rule with the specified method name.  The
     * parameter types (if any) default to java.lang.String.
     *
     * @param targetOffset location of the target object. Positive numbers are
     * relative to the top of the digester object stack. Negative numbers 
     * are relative to the bottom of the stack. Zero implies the top
     * object on the stack.
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of this element.
     */
    public CallMethodRule(int targetOffset,
                          String methodName,
                          int paramCount) {

        this.targetOffset = targetOffset;
        this.methodName = methodName;
        this.paramCount = paramCount;        
        if (paramCount == 0) {
            this.paramTypes = new Class[] { String.class };
        } else {
            this.paramTypes = new Class[paramCount];
            for (int i = 0; i < this.paramTypes.length; i++) {
                this.paramTypes[i] = String.class;
            }
        }

    }

    
Construct a "call method" rule with the specified method name.  
The method should accept no parameters.
Params:
methodName – Method name of the parent method to call/**
     * Construct a "call method" rule with the specified method name.  
     * The method should accept no parameters.
     *
     * @param methodName Method name of the parent method to call
     */
    public CallMethodRule(String methodName) {
    
        this(0, methodName, 0, (Class[]) null);
    
    }
    

    
Construct a "call method" rule with the specified method name.  
The method should accept no parameters.
Params:
targetOffset – location of the target object. Positive numbers are
relative to the top of the digester object stack. Negative numbers 
are relative to the bottom of the stack. Zero implies the top
object on the stack.
methodName – Method name of the parent method to call/**
     * Construct a "call method" rule with the specified method name.  
     * The method should accept no parameters.
     *
     * @param targetOffset location of the target object. Positive numbers are
     * relative to the top of the digester object stack. Negative numbers 
     * are relative to the bottom of the stack. Zero implies the top
     * object on the stack.
     * @param methodName Method name of the parent method to call
     */
    public CallMethodRule(int targetOffset, String methodName) {
    
        this(targetOffset, methodName, 0, (Class[]) null);
    
    }
    

    
Construct a "call method" rule with the specified method name and
parameter types. If paramCount is set to zero the rule
will use the body of this element as the single argument of the
method, unless paramTypes is null or empty, in this
case the rule will call the specified method with no arguments.
Params:
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java class names of the arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean
 for a boolean parameter)/**
     * Construct a "call method" rule with the specified method name and
     * parameter types. If <code>paramCount</code> is set to zero the rule
     * will use the body of this element as the single argument of the
     * method, unless <code>paramTypes</code> is null or empty, in this
     * case the rule will call the specified method with no arguments.
     *
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java class names of the arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean</code>
     *  for a <code>boolean</code> parameter)
     */
    public CallMethodRule(
                            String methodName,
                            int paramCount, 
                            String paramTypes[]) {
        this(0, methodName, paramCount, paramTypes);
    }

    
Construct a "call method" rule with the specified method name and
parameter types. If paramCount is set to zero the rule
will use the body of this element as the single argument of the
method, unless paramTypes is null or empty, in this
case the rule will call the specified method with no arguments.
Params:
targetOffset – location of the target object. Positive numbers are
relative to the top of the digester object stack. Negative numbers 
are relative to the bottom of the stack. Zero implies the top
object on the stack.
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java class names of the arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean
 for a boolean parameter)/**
     * Construct a "call method" rule with the specified method name and
     * parameter types. If <code>paramCount</code> is set to zero the rule
     * will use the body of this element as the single argument of the
     * method, unless <code>paramTypes</code> is null or empty, in this
     * case the rule will call the specified method with no arguments.
     *
     * @param targetOffset location of the target object. Positive numbers are
     * relative to the top of the digester object stack. Negative numbers 
     * are relative to the bottom of the stack. Zero implies the top
     * object on the stack.
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java class names of the arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean</code>
     *  for a <code>boolean</code> parameter)
     */
    public CallMethodRule(  int targetOffset,
                            String methodName,
                            int paramCount, 
                            String paramTypes[]) {

        this.targetOffset = targetOffset;
        this.methodName = methodName;
        this.paramCount = paramCount;
        if (paramTypes == null) {
            this.paramTypes = new Class[paramCount];
            for (int i = 0; i < this.paramTypes.length; i++) {
                this.paramTypes[i] = String.class;
            }
        } else {
            // copy the parameter class names into an array
            // the classes will be loaded when the digester is set 
            this.paramClassNames = new String[paramTypes.length];
            for (int i = 0; i < this.paramClassNames.length; i++) {
                this.paramClassNames[i] = paramTypes[i];
            }
        }

    }


    
Construct a "call method" rule with the specified method name and
parameter types. If paramCount is set to zero the rule
will use the body of this element as the single argument of the
method, unless paramTypes is null or empty, in this
case the rule will call the specified method with no arguments.
Params:
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java classes that represent the
 parameter types of the method arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean.TYPE
 for a boolean parameter)/**
     * Construct a "call method" rule with the specified method name and
     * parameter types. If <code>paramCount</code> is set to zero the rule
     * will use the body of this element as the single argument of the
     * method, unless <code>paramTypes</code> is null or empty, in this
     * case the rule will call the specified method with no arguments.
     *
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java classes that represent the
     *  parameter types of the method arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean.TYPE</code>
     *  for a <code>boolean</code> parameter)
     */
    public CallMethodRule(
                            String methodName,
                            int paramCount, 
                            Class<?> paramTypes[]) {
        this(0, methodName, paramCount, paramTypes);
    }

    
Construct a "call method" rule with the specified method name and
parameter types. If paramCount is set to zero the rule
will use the body of this element as the single argument of the
method, unless paramTypes is null or empty, in this
case the rule will call the specified method with no arguments.
Params:
targetOffset – location of the target object. Positive numbers are
relative to the top of the digester object stack. Negative numbers 
are relative to the bottom of the stack. Zero implies the top
object on the stack.
methodName – Method name of the parent method to call
paramCount – The number of parameters to collect, or
 zero for a single argument from the body of ths element
paramTypes – The Java classes that represent the
 parameter types of the method arguments
 (if you wish to use a primitive type, specify the corresonding
 Java wrapper class instead, such as java.lang.Boolean.TYPE
 for a boolean parameter)/**
     * Construct a "call method" rule with the specified method name and
     * parameter types. If <code>paramCount</code> is set to zero the rule
     * will use the body of this element as the single argument of the
     * method, unless <code>paramTypes</code> is null or empty, in this
     * case the rule will call the specified method with no arguments.
     *
     * @param targetOffset location of the target object. Positive numbers are
     * relative to the top of the digester object stack. Negative numbers 
     * are relative to the bottom of the stack. Zero implies the top
     * object on the stack.
     * @param methodName Method name of the parent method to call
     * @param paramCount The number of parameters to collect, or
     *  zero for a single argument from the body of ths element
     * @param paramTypes The Java classes that represent the
     *  parameter types of the method arguments
     *  (if you wish to use a primitive type, specify the corresonding
     *  Java wrapper class instead, such as <code>java.lang.Boolean.TYPE</code>
     *  for a <code>boolean</code> parameter)
     */
    public CallMethodRule(  int targetOffset,
                            String methodName,
                            int paramCount, 
                            Class<?> paramTypes[]) {

        this.targetOffset = targetOffset;
        this.methodName = methodName;
        this.paramCount = paramCount;
        if (paramTypes == null) {
            this.paramTypes = new Class[paramCount];
            for (int i = 0; i < this.paramTypes.length; i++) {
                this.paramTypes[i] = String.class;
            }
        } else {
            this.paramTypes = new Class[paramTypes.length];
            for (int i = 0; i < this.paramTypes.length; i++) {
                this.paramTypes[i] = paramTypes[i];
            }
        }

    }


    // ----------------------------------------------------- Instance Variables


    
The body text collected from this element.
/**
     * The body text collected from this element.
     */
    protected String bodyText = null;


    
location of the target object for the call, relative to the
top of the digester object stack. The default value of zero
means the target object is the one on top of the stack.
/** 
     * location of the target object for the call, relative to the
     * top of the digester object stack. The default value of zero
     * means the target object is the one on top of the stack.
     */
    protected int targetOffset = 0;

    
The method name to call on the parent object.
/**
     * The method name to call on the parent object.
     */
    protected String methodName = null;


    
The number of parameters to collect from MethodParam rules.
If this value is zero, a single parameter will be collected from the
body of this element.
/**
     * The number of parameters to collect from <code>MethodParam</code> rules.
     * If this value is zero, a single parameter will be collected from the
     * body of this element.
     */
    protected int paramCount = 0;


    
The parameter types of the parameters to be collected.
/**
     * The parameter types of the parameters to be collected.
     */
    protected Class<?> paramTypes[] = null;

    
The names of the classes of the parameters to be collected.
This attribute allows creation of the classes to be postponed until the digester is set.
/**
     * The names of the classes of the parameters to be collected.
     * This attribute allows creation of the classes to be postponed until the digester is set.
     */
    private String paramClassNames[] = null;
    
    
Should MethodUtils.invokeExactMethod be used for reflection.
/**
     * Should <code>MethodUtils.invokeExactMethod</code> be used for reflection.
     */
    protected boolean useExactMatch = false;
    
    // --------------------------------------------------------- Public Methods
    
    
Should MethodUtils.invokeExactMethod
be used for the reflection.
/**
     * Should <code>MethodUtils.invokeExactMethod</code>
     * be used for the reflection.
     */
    public boolean getUseExactMatch() {
        return useExactMatch;
    }
    
    
Set whether MethodUtils.invokeExactMethod
should be used for the reflection.
/**
     * Set whether <code>MethodUtils.invokeExactMethod</code>
     * should be used for the reflection.
     */    
    public void setUseExactMatch(boolean useExactMatch)
    { 
        this.useExactMatch = useExactMatch;
    }

    
Set the associated digester.
If needed, this class loads the parameter classes from their names.
/**
     * Set the associated digester.
     * If needed, this class loads the parameter classes from their names.
     */
    @Override
    public void setDigester(Digester digester)
    {
        // call superclass
        super.setDigester(digester);
        // if necessary, load parameter classes
        if (this.paramClassNames != null) {
            this.paramTypes = new Class[paramClassNames.length];
            for (int i = 0; i < this.paramClassNames.length; i++) {
                try {
                    this.paramTypes[i] =
                            digester.getClassLoader().loadClass(this.paramClassNames[i]);
                } catch (ClassNotFoundException e) {
                    // use the digester log
                    digester.getLogger().error("(CallMethodRule) Cannot load class " + this.paramClassNames[i], e);
                    this.paramTypes[i] = null; // Will cause NPE later
                }
            }
        }
    }

    
Process the start of this element.
Params:
attributes – The attribute list for this element/**
     * Process the start of this element.
     *
     * @param attributes The attribute list for this element
     */
    @Override
    public void begin(Attributes attributes) throws Exception {

        // Push an array to capture the parameter values if necessary
        if (paramCount > 0) {
            Object parameters[] = new Object[paramCount];
            for (int i = 0; i < parameters.length; i++) {
                parameters[i] = null;
            }
            digester.pushParams(parameters);
        }

    }


    
Process the body text of this element.
Params:
bodyText – The body text of this element/**
     * Process the body text of this element.
     *
     * @param bodyText The body text of this element
     */
    @Override
    public void body(String bodyText) throws Exception {

        if (paramCount == 0) {
            this.bodyText = bodyText.trim();
        }

    }


    
Process the end of this element.
/**
     * Process the end of this element.
     */
    @Override
    public void end() throws Exception {

        // Retrieve or construct the parameter values array
        Object parameters[] = null;
        if (paramCount > 0) {

            parameters = (Object[]) digester.popParams();
            
            if (digester.log.isTraceEnabled()) {
                for (int i=0,size=parameters.length;i<size;i++) {
                    digester.log.trace("[CallMethodRule](" + i + ")" + parameters[i]) ;
                }
            }
            
            // In the case where the target method takes a single parameter
            // and that parameter does not exist (the CallParamRule never
            // executed or the CallParamRule was intended to set the parameter
            // from an attribute but the attribute wasn't present etc) then
            // skip the method call.
            //
            // This is useful when a class has a "default" value that should
            // only be overridden if data is present in the XML. I don't
            // know why this should only apply to methods taking *one*
            // parameter, but it always has been so we can't change it now.
            if (paramCount == 1 && parameters[0] == null) {
                return;
            }

        } else if (paramTypes != null && paramTypes.length != 0) {
            // Having paramCount == 0 and paramTypes.length == 1 indicates
            // that we have the special case where the target method has one
            // parameter being the body text of the current element.

            // There is no body text included in the source XML file,
            // so skip the method call
            if (bodyText == null) {
                return;
            }

            parameters = new Object[1];
            parameters[0] = bodyText;
            if (paramTypes.length == 0) {
                paramTypes = new Class[1];
                paramTypes[0] = String.class;
            }

        } else {
            // When paramCount is zero and paramTypes.length is zero it
            // means that we truly are calling a method with no parameters.
            // Nothing special needs to be done here.
        }

        // Construct the parameter values array we will need
        // We only do the conversion if the param value is a String and
        // the specified paramType is not String. 
        Object paramValues[] = new Object[paramTypes.length];
        for (int i = 0; i < paramTypes.length; i++) {
            // convert nulls and convert stringy parameters 
            // for non-stringy param types
            if(
                parameters[i] == null ||
                 (parameters[i] instanceof String && 
                   !String.class.isAssignableFrom(paramTypes[i]))) {
                
                paramValues[i] =
                        ConvertUtils.convert((String) parameters[i], paramTypes[i]);
            } else {
                paramValues[i] = parameters[i];
            }
        }

        // Determine the target object for the method call
        Object target;
        if (targetOffset >= 0) {
            target = digester.peek(targetOffset);
        } else {
            target = digester.peek( digester.getCount() + targetOffset );
        }
        
        if (target == null) {
            StringBuffer sb = new StringBuffer();
            sb.append("[CallMethodRule]{");
            sb.append(digester.match);
            sb.append("} Call target is null (");
            sb.append("targetOffset=");
            sb.append(targetOffset);
            sb.append(",stackdepth=");
            sb.append(digester.getCount());
            sb.append(")");
            throw new org.xml.sax.SAXException(sb.toString());
        }
        
        // Invoke the required method on the top object
        if (digester.log.isDebugEnabled()) {
            StringBuffer sb = new StringBuffer("[CallMethodRule]{");
            sb.append(digester.match);
            sb.append("} Call ");
            sb.append(target.getClass().getName());
            sb.append(".");
            sb.append(methodName);
            sb.append("(");
            for (int i = 0; i < paramValues.length; i++) {
                if (i > 0) {
                    sb.append(",");
                }
                if (paramValues[i] == null) {
                    sb.append("null");
                } else {
                    sb.append(paramValues[i].toString());
                }
                sb.append("/");
                if (paramTypes[i] == null) {
                    sb.append("null");
                } else {
                    sb.append(paramTypes[i].getName());
                }
            }
            sb.append(")");
            digester.log.debug(sb.toString());
        }
        
        Object result = null;
        if (useExactMatch) {
            // invoke using exact match
            result = MethodUtils.invokeExactMethod(target, methodName,
                paramValues, paramTypes);
                
        } else {
            // invoke using fuzzier match
            result = MethodUtils.invokeMethod(target, methodName,
                paramValues, paramTypes);            
        }
        
        processMethodCallResult(result);
    }


    
Clean up after parsing is complete.
/**
     * Clean up after parsing is complete.
     */
    @Override
    public void finish() throws Exception {

        bodyText = null;

    }

    
Subclasses may override this method to perform additional processing of the 
invoked method's result.
Params:
result – the Object returned by the method invoked, possibly null/**
     * Subclasses may override this method to perform additional processing of the 
     * invoked method's result.
     *
     * @param result the Object returned by the method invoked, possibly null
     */
    protected void processMethodCallResult(Object result) {
        // do nothing
    }

    
Render a printable version of this Rule.
/**
     * Render a printable version of this Rule.
     */
    @Override
    public String toString() {

        StringBuffer sb = new StringBuffer("CallMethodRule[");
        sb.append("methodName=");
        sb.append(methodName);
        sb.append(", paramCount=");
        sb.append(paramCount);
        sb.append(", paramTypes={");
        if (paramTypes != null) {
            for (int i = 0; i < paramTypes.length; i++) {
                if (i > 0) {
                    sb.append(", ");
                }
                sb.append(paramTypes[i].getName());
            }
        }
        sb.append("}");
        sb.append("]");
        return (sb.toString());

    }


}