callmethodrule.java

JAVA 文章管理系统源码

                            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] = "abc".getClass();
            }
        } 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.
     */
    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.
     */
    private int targetOffset = 0;

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


    /**
     * 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.
     */
    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.
     */
    private String paramClassNames[] = null;
    
    /**
     * Should <code>MethodUtils.invokeExactMethod</code> be used for reflection.
     */
    protected boolean useExactMatch = false;
    
    // --------------------------------------------------------- Public Methods
    
    /**
     * Should <code>MethodUtils.invokeExactMethod</code>
     * be used for the reflection.
     */
    public boolean getUseExactMatch() {
        return useExactMatch;
    }
    
    /**
     * 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.
     */
    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.
     *
     * @param attributes The attribute list for this element
     */
    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.
     *
     * @param bodyText The body text of this element
     */
    public void body(String bodyText) throws Exception {

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

    }


    /**
     * Process the end of this element.
     */
    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 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;
            if (paramTypes.length == 0) {
                paramTypes = new Class[1];
                paramTypes[0] = "abc".getClass();
            }

        }

        // 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.
     */
    public void finish() throws Exception {

        bodyText = 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.
     */
    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());

    }


}