org.opencms.configuration.CmsSetNextRule Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* For further information about Alkacon Software GmbH & Co. KG, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* This file is based upon:
* org.apache.commons.digester3.CallMethodRule.
*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed 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.opencms.configuration;
import org.opencms.file.CmsObject;
import org.opencms.main.CmsLog;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.MethodUtils;
import org.apache.commons.digester3.Digester;
import org.apache.commons.digester3.Rule;
import org.apache.commons.logging.Log;
import org.xml.sax.Attributes;
/**
* Rule implementation that invokes a method on the (top-1) (parent) object,
* passing as implicit first argument of type {@link org.opencms.file.CmsObject}
* and as a further argument the top stack instance.
*
* If no subsequent CallParamRule are matched for CmsObject
* which is the case in the OpenCms usage the first argument CmsObject
* will be null at method invocation time.
* This is an alternative for {@link org.apache.commons.digester3.SetNextRule}
* if a parent to child-property configuration has been done but the setter for that
* property requires additional arguments that are only available at real runtime
* of the application.
*
* The top stack element (child) that has to be set is matched against the constructor
* given {@link java.lang.Class}[]: It is used as argument on the position
* where the Class[] has an instance of the same type as it's own Class.
*
* @see org.apache.commons.digester3.CallMethodRule
* @see org.apache.commons.digester3.SetNextRule
*
* @since 6.0.0
*/
public class CmsSetNextRule extends Rule {
/** The log object of this class. */
private static final Log LOG = CmsLog.getLog(CmsSetNextRule.class);
/**
* The body text collected from this element.
*/
protected String m_bodyText;
/**
* The method name to call on the parent object.
*/
protected String m_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.
*/
protected int m_paramCount;
/**
* The parameter types of the parameters to be collected.
*/
protected Class[] m_paramTypes;
/**
* Should MethodUtils.invokeExactMethod be used for reflection.
*/
protected boolean m_useExactMatch;
/**
* 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 m_targetOffset;
/**
* Construct a "call method" rule with the specified method name.
*
*
* The 1st argument of the method will be of type {@link CmsObject}.
* It's value will remain null (except subsequent
* {@link org.apache.commons.digester3.CallParamRule} would put a value
* which currently is impossible at initialization time within OpenCms).
*
* The 2nd argument will be the top-stack element at digestion time.
* That instance has to be of the same type as the clazz argument to succeed.
*
*
* @param methodName Method name of the parent method to call
* @param clazz The class of the top-stack element (child) that will be present at digestion-time
*/
public CmsSetNextRule(String methodName, Class clazz) {
this(methodName, new Class[] {clazz});
}
/**
* Construct a "call method" rule with the specified method name
* and additional parameters.
*
*
* The 1st argument of the method will be of type {@link CmsObject}.
* It's value will remain null (except subsequent
* {@link org.apache.commons.digester3.CallParamRule} would put a value
* which currently is impossible at initialization time within OpenCms).
*
* The further arguments will be filled by the subsequent {@link org.apache.commons.digester3.CallParamRule}
* matches. If the first Class in the given array matches the top stack element
* (child) that value will be used. If at digestion time no parameters are found for the given
* types their values for invocation of the method remain null.
*
*
* @param methodName Method name of the parent method to call
* @param clazzes an array with all parameter types for the method to invoke at digestion time
*/
public CmsSetNextRule(String methodName, Class[] clazzes) {
m_targetOffset = 0;
m_methodName = methodName;
m_paramCount = clazzes.length + 1;
m_paramTypes = new Class[m_paramCount];
m_paramTypes[0] = CmsObject.class;
System.arraycopy(clazzes, 0, m_paramTypes, 1, clazzes.length);
}
/**
* Process the start of this element.
*
* @param attributes The attribute list for 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
* @throws Exception if something goes wrong
*/
@Override
public void begin(String namespace, String name, Attributes attributes) throws Exception {
// not now: 6.0.0
// digester.setLogger(CmsLog.getLog(digester.getClass()));
// Push an array to capture the parameter values if necessary
if (m_paramCount > 0) {
Object[] parameters = new Object[m_paramCount];
for (int i = 0; i < parameters.length; i++) {
parameters[i] = null;
}
getDigester().pushParams(parameters);
}
}
/**
* Process the body text of this element.
*
* @param bodyText 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
* @throws Exception if something goes wrong
*/
@Override
public void body(String namespace, String name, String bodyText) throws Exception {
if (m_paramCount == 0) {
m_bodyText = bodyText.trim();
}
}
/**
* 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
* @throws Exception if something goes wrong
*/
@Override
public void end(String namespace, String name) throws Exception {
// Determine the target object for the method call: the parent object
Object parent = getDigester().peek(1);
Object child = getDigester().peek(0);
// Retrieve or construct the parameter values array
Object[] parameters = null;
if (m_paramCount > 0) {
parameters = getDigester().popParams();
if (LOG.isTraceEnabled()) {
for (int i = 0, size = parameters.length; i < size; i++) {
LOG.trace("[SetNextRuleWithParams](" + 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 ((m_paramCount == 1) && (parameters[0] == null)) {
return;
}
} else if (m_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 (m_bodyText == null) {
return;
}
parameters = new Object[1];
parameters[0] = m_bodyText;
if (m_paramTypes.length == 0) {
m_paramTypes = new Class[1];
m_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.
parameters = new Object[0];
}
// 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[m_paramTypes.length];
Class propertyClass = child.getClass();
for (int i = 0; i < m_paramTypes.length; i++) {
if (m_paramTypes[i] == propertyClass) {
// implant the original child to set if Class matches:
paramValues[i] = child;
} else if ((parameters[i] == null)
|| ((parameters[i] instanceof String) && !String.class.isAssignableFrom(m_paramTypes[i]))) {
// convert nulls and convert stringy parameters
// for non-stringy param types
if (parameters[i] == null) {
paramValues[i] = null;
} else {
paramValues[i] = ConvertUtils.convert((String)parameters[i], m_paramTypes[i]);
}
} else {
paramValues[i] = parameters[i];
}
}
if (parent == null) {
StringBuffer sb = new StringBuffer();
sb.append("[SetNextRuleWithParams]{");
sb.append(getDigester().getMatch());
sb.append("} Call target is null (");
sb.append("targetOffset=");
sb.append(m_targetOffset);
sb.append(",stackdepth=");
sb.append(getDigester().getCount());
sb.append(")");
throw new org.xml.sax.SAXException(sb.toString());
}
// Invoke the required method on the top object
if (LOG.isDebugEnabled()) {
StringBuffer sb = new StringBuffer("[SetNextRuleWithParams]{");
sb.append(getDigester().getMatch());
sb.append("} Call ");
sb.append(parent.getClass().getName());
sb.append(".");
sb.append(m_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 (m_paramTypes[i] == null) {
sb.append("null");
} else {
sb.append(m_paramTypes[i].getName());
}
}
sb.append(")");
LOG.debug(sb.toString());
}
Object result = null;
if (m_useExactMatch) {
// invoke using exact match
result = MethodUtils.invokeExactMethod(parent, m_methodName, paramValues, m_paramTypes);
} else {
// invoke using fuzzier match
result = MethodUtils.invokeMethod(parent, m_methodName, paramValues, m_paramTypes);
}
processMethodCallResult(result);
}
/**
* Clean up after parsing is complete.
*
* @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
* @throws Exception if something goes wrong
*/
public void finish(String namespace, String name) throws Exception {
String dummy = name;
dummy = namespace;
dummy = null;
m_bodyText = dummy;
}
/**
* Returns true if MethodUtils.invokeExactMethod
* shall be used for the reflection.
*
* @return true if MethodUtils.invokeExactMethod
* shall be used for the reflection.
*/
public boolean getUseExactMatch() {
return m_useExactMatch;
}
/**
* Set the associated digester.
*
* The digester gets assigned to use the OpenCms conform logging
*
* If needed, this class loads the parameter classes from their names.
*
* @param aDigester the associated digester to set
*/
@Override
public void setDigester(Digester aDigester) {
aDigester.setLogger(CmsLog.getLog(aDigester.getClass()));
// call superclass
super.setDigester(aDigester);
}
/**
* Set the value to use for MethodUtils.invokeExactMethod
* to use.
*
* @param useExactMatch the value to use for MethodUtils.invokeExactMethod
* to use
*/
public void setUseExactMatch(boolean useExactMatch) {
m_useExactMatch = useExactMatch;
}
/**
* Returns a printable version of this Rule.
*
* @return a printable version of this Rule
*/
@Override
public String toString() {
StringBuffer sb = new StringBuffer("CallMethodRule[");
sb.append("methodName=");
sb.append(m_methodName);
sb.append(", paramCount=");
sb.append(m_paramCount);
sb.append(", paramTypes={");
if (m_paramTypes != null) {
for (int i = 0; i < m_paramTypes.length; i++) {
if (i > 0) {
sb.append(", ");
}
sb.append(m_paramTypes[i].getName());
}
}
sb.append("}");
sb.append("]");
return (sb.toString());
}
/**
* 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 but to fool checkstyle
if (result != null) {
// nop
}
}
}