Struts example source code file (ScriptingVariabler.java)

This example Struts source code file (ScriptingVariabler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

customtagcounter, errordispatcher, hashtable, integer, integer, jasperexception, jasperexception, jsp, max_scope, max_scope, scriptingvariabler, scriptingvariablevisitor, scriptingvariablevisitor, servlet, string, util, vector

The Struts ScriptingVariabler.java source code

/*
 * 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.struts2.jasper.compiler;

import java.util.*;
import javax.servlet.jsp.tagext.*;
import org.apache.struts2.jasper.JasperException;

/**
 * Class responsible for determining the scripting variables that every
 * custom action needs to declare.
 *
 * @author Jan Luehe
 */
class ScriptingVariabler {

    private static final Integer MAX_SCOPE = new Integer(Integer.MAX_VALUE);

    /*
     * Assigns an identifier (of type integer) to every custom tag, in order
     * to help identify, for every custom tag, the scripting variables that it
     * needs to declare.
     */
    static class CustomTagCounter extends Node.Visitor {

	private int count;
	private Node.CustomTag parent;

	public void visit(Node.CustomTag n) throws JasperException {
	    n.setCustomTagParent(parent);
	    Node.CustomTag tmpParent = parent;
	    parent = n;
	    visitBody(n);
	    parent = tmpParent;
	    n.setNumCount(new Integer(count++));
	}
    }

    /*
     * For every custom tag, determines the scripting variables it needs to
     * declare. 
     */
    static class ScriptingVariableVisitor extends Node.Visitor {

	private ErrorDispatcher err;
	private Hashtable scriptVars;
	
	public ScriptingVariableVisitor(ErrorDispatcher err) {
	    this.err = err;
	    scriptVars = new Hashtable();
	}

	public void visit(Node.CustomTag n) throws JasperException {
	    setScriptingVars(n, VariableInfo.AT_BEGIN);
	    setScriptingVars(n, VariableInfo.NESTED);
	    visitBody(n);
	    setScriptingVars(n, VariableInfo.AT_END);
	}

	private void setScriptingVars(Node.CustomTag n, int scope)
	        throws JasperException {

	    TagVariableInfo[] tagVarInfos = n.getTagVariableInfos();
	    VariableInfo[] varInfos = n.getVariableInfos();
	    if (tagVarInfos.length == 0 && varInfos.length == 0) {
		return;
	    }

	    Vector vec = new Vector();

	    Integer ownRange = null;
	    if (scope == VariableInfo.AT_BEGIN
		    || scope == VariableInfo.AT_END) {
		Node.CustomTag parent = n.getCustomTagParent();
		if (parent == null)
		    ownRange = MAX_SCOPE;
		else
		    ownRange = parent.getNumCount();
	    } else {
		// NESTED
		ownRange = n.getNumCount();
	    }

	    if (varInfos.length > 0) {
		for (int i=0; i<varInfos.length; i++) {
		    if (varInfos[i].getScope() != scope
			    || !varInfos[i].getDeclare()) {
			continue;
		    }
		    String varName = varInfos[i].getVarName();
		    
		    Integer currentRange = (Integer) scriptVars.get(varName);
		    if (currentRange == null
			    || ownRange.compareTo(currentRange) > 0) {
			scriptVars.put(varName, ownRange);
			vec.add(varInfos[i]);
		    }
		}
	    } else {
		for (int i=0; i<tagVarInfos.length; i++) {
		    if (tagVarInfos[i].getScope() != scope
			    || !tagVarInfos[i].getDeclare()) {
			continue;
		    }
		    String varName = tagVarInfos[i].getNameGiven();
		    if (varName == null) {
			varName = n.getTagData().getAttributeString(
		                        tagVarInfos[i].getNameFromAttribute());
			if (varName == null) {
			    err.jspError(n, "jsp.error.scripting.variable.missing_name",
					 tagVarInfos[i].getNameFromAttribute());
			}
		    }

		    Integer currentRange = (Integer) scriptVars.get(varName);
		    if (currentRange == null
			    || ownRange.compareTo(currentRange) > 0) {
			scriptVars.put(varName, ownRange);
			vec.add(tagVarInfos[i]);
		    }
		}
	    }

	    n.setScriptingVars(vec, scope);
	}
    }

    public static void set(Node.Nodes page, ErrorDispatcher err)
	    throws JasperException {
	page.visit(new CustomTagCounter());
	page.visit(new ScriptingVariableVisitor(err));
    }
}