Package org.apache.tomcat.util.digester

Class CallMethodRule

  • public class CallMethodRule
extends Rule

    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).

    • Field Detail

      • bodyText

        protected String bodyText
        The body text collected from this element.

      • targetOffset

        protected int targetOffset
        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.

      • methodName

        protected String methodName
        The method name to call on the parent object.

      • paramCount

        protected int paramCount
        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.

      • paramTypes

        protected Class<?>[] paramTypes
        The parameter types of the parameters to be collected.

      • paramClassNames

        protected String[] paramClassNames
        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.

      • useExactMatch

        protected boolean useExactMatch
        Should MethodUtils.invokeExactMethod be used for reflection.

    • Constructor Detail

      • CallMethodRule

        public CallMethodRule​(Digester digester,
                      String methodName,
                      int paramCount,
                      Class[] paramTypes)
        Deprecated.
        The digester instance is now set in the Digester.addRule(java.lang.String, org.apache.tomcat.util.digester.Rule) method. Use CallMethodRule(String methodName,int paramCount, Class [] paramTypes) instead.
        Construct a "call method" rule with the specified method name.
        Parameters:
        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)

      • CallMethodRule

        public CallMethodRule​(String methodName,
                      int paramCount)
        Construct a "call method" rule with the specified method name. The parameter types (if any) default to java.lang.String.
        Parameters:
        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.

      • CallMethodRule

        public CallMethodRule​(int targetOffset,
                      String methodName,
                      int paramCount)
        Construct a "call method" rule with the specified method name. The parameter types (if any) default to java.lang.String.
        Parameters:
        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.

      • CallMethodRule

        public CallMethodRule​(String methodName)
        Construct a "call method" rule with the specified method name. The method should accept no parameters.
        Parameters:
        methodName - Method name of the parent method to call

      • CallMethodRule

        public CallMethodRule​(int targetOffset,
                      String methodName)
        Construct a "call method" rule with the specified method name. The method should accept no parameters.
        Parameters:
        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

      • CallMethodRule

        public CallMethodRule​(String methodName,
                      int paramCount,
                      String[] 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.
        Parameters:
        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)

      • CallMethodRule

        public CallMethodRule​(int targetOffset,
                      String methodName,
                      int paramCount,
                      String[] 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.
        Parameters:
        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)

      • CallMethodRule

        public CallMethodRule​(String methodName,
                      int paramCount,
                      Class<?>[] 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.
        Parameters:
        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)

      • CallMethodRule

        public CallMethodRule​(int targetOffset,
                      String methodName,
                      int paramCount,
                      Class<?>[] 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.
        Parameters:
        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)

    • Method Detail

      • getUseExactMatch

        public boolean getUseExactMatch()
        Should MethodUtils.invokeExactMethod be used for the reflection.

      • setUseExactMatch

        public void setUseExactMatch​(boolean useExactMatch)
        Set whether MethodUtils.invokeExactMethod should be used for the reflection.

      • setDigester

        public void setDigester​(Digester digester)
        Set the associated digester. If needed, this class loads the parameter classes from their names.
        Overrides:
        setDigester in class Rule

      • begin

        public void begin​(Attributes attributes)
           throws Exception
        Process the start of this element.
        Overrides:
        begin in class Rule
        Parameters:
        attributes - The attribute list for this element
        Throws:
        Exception

      • body

        public void body​(String bodyText)
          throws Exception
        Process the body text of this element.
        Overrides:
        body in class Rule
        Parameters:
        bodyText - The body text of this element
        Throws:
        Exception

      • processMethodCallResult

        protected void processMethodCallResult​(Object result)
        Subclasses may override this method to perform additional processing of the invoked method's result.
        Parameters:
        result - the Object returned by the method invoked, possibly null

      • toString

        public String toString()
        Render a printable version of this Rule.
        Overrides:
        toString in class Object