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Struts example source code file (Collector.java)

This example Struts source code file (Collector.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

collector, collector, collectvisitor, collectvisitor, jasperexception, jasperexception, node, node

The Struts Collector.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 org.apache.struts2.jasper.JasperException;

/**
 * Collect info about the page and nodes, and make them availabe through
 * the PageInfo object.
 *
 * @author Kin-man Chung
 * @author Mark Roth
 */

class Collector {

    /**
     * A visitor for collecting information on the page and the body of
     * the custom tags.
     */
    static class CollectVisitor extends Node.Visitor {

        private boolean scriptingElementSeen = false;
        private boolean usebeanSeen = false;
        private boolean includeActionSeen = false;
        private boolean paramActionSeen = false;
        private boolean setPropertySeen = false;
        private boolean hasScriptingVars = false;

        public void visit(Node.ParamAction n) throws JasperException {
            if (n.getValue().isExpression()) {
                scriptingElementSeen = true;
            }
            paramActionSeen = true;
        }

        public void visit(Node.IncludeAction n) throws JasperException {
            if (n.getPage().isExpression()) {
                scriptingElementSeen = true;
            }
            includeActionSeen = true;
            visitBody(n);
        }

        public void visit(Node.ForwardAction n) throws JasperException {
            if (n.getPage().isExpression()) {
                scriptingElementSeen = true;
            }
            visitBody(n);
        }

        public void visit(Node.SetProperty n) throws JasperException {
            if (n.getValue() != null && n.getValue().isExpression()) {
                scriptingElementSeen = true;
            }
            setPropertySeen = true;
        }

        public void visit(Node.UseBean n) throws JasperException {
            if (n.getBeanName() != null && n.getBeanName().isExpression()) {
                scriptingElementSeen = true;
            }
            usebeanSeen = true;
                visitBody(n);
        }

        public void visit(Node.PlugIn n) throws JasperException {
            if (n.getHeight() != null && n.getHeight().isExpression()) {
                scriptingElementSeen = true;
            }
            if (n.getWidth() != null && n.getWidth().isExpression()) {
                scriptingElementSeen = true;
            }
            visitBody(n);
        }

        public void visit(Node.CustomTag n) throws JasperException {
            // Check to see what kinds of element we see as child elements
            checkSeen( n.getChildInfo(), n );
        }

        /**
         * Check all child nodes for various elements and update the given
         * ChildInfo object accordingly.  Visits body in the process.
         */
        private void checkSeen( Node.ChildInfo ci, Node n )
            throws JasperException
        {
            // save values collected so far
            boolean scriptingElementSeenSave = scriptingElementSeen;
            scriptingElementSeen = false;
            boolean usebeanSeenSave = usebeanSeen;
            usebeanSeen = false;
            boolean includeActionSeenSave = includeActionSeen;
            includeActionSeen = false;
            boolean paramActionSeenSave = paramActionSeen;
            paramActionSeen = false;
            boolean setPropertySeenSave = setPropertySeen;
            setPropertySeen = false;
            boolean hasScriptingVarsSave = hasScriptingVars;
            hasScriptingVars = false;

            // Scan attribute list for expressions
            if( n instanceof Node.CustomTag ) {
                Node.CustomTag ct = (Node.CustomTag)n;
                Node.JspAttribute[] attrs = ct.getJspAttributes();
                for (int i = 0; attrs != null && i < attrs.length; i++) {
                    if (attrs[i].isExpression()) {
                        scriptingElementSeen = true;
                        break;
                    }
                }
            }

            visitBody(n);

            if( (n instanceof Node.CustomTag) && !hasScriptingVars) {
                Node.CustomTag ct = (Node.CustomTag)n;
                hasScriptingVars = ct.getVariableInfos().length > 0 ||
                    ct.getTagVariableInfos().length > 0;
            }

            // Record if the tag element and its body contains any scriptlet.
            ci.setScriptless(! scriptingElementSeen);
            ci.setHasUseBean(usebeanSeen);
            ci.setHasIncludeAction(includeActionSeen);
            ci.setHasParamAction(paramActionSeen);
            ci.setHasSetProperty(setPropertySeen);
            ci.setHasScriptingVars(hasScriptingVars);

            // Propagate value of scriptingElementSeen up.
            scriptingElementSeen = scriptingElementSeen || scriptingElementSeenSave;
            usebeanSeen = usebeanSeen || usebeanSeenSave;
            setPropertySeen = setPropertySeen || setPropertySeenSave;
            includeActionSeen = includeActionSeen || includeActionSeenSave;
            paramActionSeen = paramActionSeen || paramActionSeenSave;
            hasScriptingVars = hasScriptingVars || hasScriptingVarsSave;
        }

        public void visit(Node.JspElement n) throws JasperException {
            if (n.getNameAttribute().isExpression())
                scriptingElementSeen = true;

            Node.JspAttribute[] attrs = n.getJspAttributes();
            for (int i = 0; i < attrs.length; i++) {
                if (attrs[i].isExpression()) {
                    scriptingElementSeen = true;
                    break;
                }
            }
            visitBody(n);
        }

        public void visit(Node.JspBody n) throws JasperException {
            checkSeen( n.getChildInfo(), n );
        }

        public void visit(Node.NamedAttribute n) throws JasperException {
            checkSeen( n.getChildInfo(), n );
        }

        public void visit(Node.Declaration n) throws JasperException {
            scriptingElementSeen = true;
        }

        public void visit(Node.Expression n) throws JasperException {
            scriptingElementSeen = true;
        }

        public void visit(Node.Scriptlet n) throws JasperException {
            scriptingElementSeen = true;
        }

        public void updatePageInfo(PageInfo pageInfo) {
            pageInfo.setScriptless(! scriptingElementSeen);
        }
    }


    public static void collect(Compiler compiler, Node.Nodes page)
        throws JasperException {

    CollectVisitor collectVisitor = new CollectVisitor();
        page.visit(collectVisitor);
        collectVisitor.updatePageInfo(compiler.getPageInfo());

    }
}

Other Struts examples (source code examples)

Here is a short list of links related to this Struts Collector.java source code file:

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