/*
 * 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.tomcat.util.digester;

import org.apache.tomcat.util.IntrospectionUtils;
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

org.apache.commons.beanutils.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 org.apache.commons.beanutils.MethodUtils#invokeExactMethod
(the old default) is required.
This method is much stricter in its 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 passed as null values).
/**
 * <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
 * <a href="https://commons.apache.org/beanutils/apidocs/org/apache/commons/beanutils/MethodUtils.html">
 * org.apache.commons.beanutils.MethodUtils#invokeMethod
 * </a> 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 org.apache.commons.beanutils.MethodUtils#invokeExactMethod
 * (the old default) is required.
 * This method is much stricter in its 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 passed as null values).</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:
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, 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:
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
paramTypes – The Java classes that represent the
 parameter types of the method arguments
 (if you wish to use a primitive type, specify the corresponding
 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 this 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 corresponding
     *  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];
            System.arraycopy(paramTypes, 0, this.paramTypes, 0, this.paramTypes.length);
        }
    }


    // ----------------------------------------------------- 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 final int targetOffset;


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


    
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 final int paramCount;


    
The parameter types of the parameters to be collected.
/**
     * The parameter types of the parameters to be collected.
     */
    protected Class<?> paramTypes[] = 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.
Returns:
true if invokeExactMethod is used/**
     * Should <code>MethodUtils.invokeExactMethod</code>
     * be used for the reflection.
     * @return <code>true</code> if invokeExactMethod is used
     */
    public boolean getUseExactMatch() {
        return useExactMatch;
    }


    
Set whether MethodUtils.invokeExactMethod
should be used for the reflection.
Params:
useExactMatch – The flag value/**
     * Set whether <code>MethodUtils.invokeExactMethod</code>
     * should be used for the reflection.
     * @param useExactMatch The flag value
     */
    public void setUseExactMatch(boolean useExactMatch) {
        this.useExactMatch = useExactMatch;
    }


    
Process the start of this element.
Params:
namespace – the namespace URI of the matching element, or an
  empty string if the parser is not namespace aware or the element has
  no namespace
name – the local name if the parser is namespace aware, or just
  the element name otherwise
attributes – The attribute list for this element/**
     * Process the start of this element.
     *
     * @param namespace the namespace URI of the matching element, or an
     *   empty string if the parser is not namespace aware or the element has
     *   no namespace
     * @param name the local name if the parser is namespace aware, or just
     *   the element name otherwise
     * @param attributes The attribute list for this element
     */
    @Override
    public void begin(String namespace, String name, 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:
namespace – the namespace URI of the matching element, or an
  empty string if the parser is not namespace aware or the element has
  no namespace
name – the local name if the parser is namespace aware, or just
  the element name otherwise
bodyText – The body text of this element/**
     * Process the body text of this element.
     *
     * @param namespace the namespace URI of the matching element, or an
     *   empty string if the parser is not namespace aware or the element has
     *   no namespace
     * @param name the local name if the parser is namespace aware, or just
     *   the element name otherwise
     * @param bodyText The body text of this element
     */
    @Override
    public void body(String namespace, String name, String bodyText)
            throws Exception {

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

    }


    
Process the end of this element.
Params:
namespace – the namespace URI of the matching element, or an
  empty string if the parser is not namespace aware or the element has
  no namespace
name – the local name if the parser is namespace aware, or just
  the element name otherwise/**
     * Process the end of this element.
     *
     * @param namespace the namespace URI of the matching element, or an
     *   empty string if the parser is not namespace aware or the element has
     *   no namespace
     * @param name the local name if the parser is namespace aware, or just
     *   the element name otherwise
     */
    @SuppressWarnings("null") // parameters can't trigger NPE
    @Override
    public void end(String namespace, String name) 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 parameter for the method
            // is taken from an attribute, and that attribute
            // isn't actually defined in the source XML file,
            // skip the method call
            if (paramCount == 1 && parameters[0] == null) {
                return;
            }

        } else if (paramTypes != null && paramTypes.length != 0) {

            // In the case where the parameter for the method
            // is taken from the body text, but there is no
            // body text included in the source XML file,
            // skip the method call
            if (bodyText == null) {
                return;
            }

            parameters = new Object[1];
            parameters[0] = bodyText;
        }

        // 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
            Object param = parameters[i];
            // Tolerate null non-primitive values
            if(null == param && !paramTypes[i].isPrimitive())
                paramValues[i] = null;
            else if(param instanceof String &&
                    !String.class.isAssignableFrom(paramTypes[i])) {

                paramValues[i] =
                        IntrospectionUtils.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) {
            StringBuilder sb = new StringBuilder();
            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()) {
            StringBuilder sb = new StringBuilder("[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 = IntrospectionUtils.callMethodN(target, methodName,
                paramValues, paramTypes);
        processMethodCallResult(result);

        StringBuilder code = digester.getGeneratedCode();
        if (code != null) {
            code.append(digester.toVariableName(target)).append('.').append(methodName);
            code.append('(');
            for (int i = 0; i < paramValues.length; i++) {
                if (i > 0) {
                    code.append(", ");
                }
                if (bodyText != null) {
                    StringBuilder bodyTextParam = new StringBuilder();
                    for (String bodyPart : bodyText.split("\n")) {
                        bodyTextParam.append(bodyPart.trim()).append(' ');
                    }
                    code.append("\"").append(bodyTextParam.toString().trim().replace("\"", "\\\"")).append("\"");
                } else if (paramValues[i] instanceof String) {
                    code.append("\"").append(paramValues[i].toString()).append("\"");
                } else {
                    code.append(digester.toVariableName(paramValues[i]));
                }
            }
            code.append(");");
            code.append(System.lineSeparator());
        }
    }


    
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() {
        StringBuilder sb = new StringBuilder("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();
    }
}