Struts example source code file (TextOptimizer.java)

This example Struts source code file (TextOptimizer.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

jasperexception, jasperexception, options, options, pageinfo, string, string, stringbuffer, textcatvisitor, textcatvisitor, textoptimizer

The Struts TextOptimizer.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;
import org.apache.struts2.jasper.Options;

/**
 */
public class TextOptimizer {

    /**
     * A visitor to concatenate contiguous template texts.
     */
    static class TextCatVisitor extends Node.Visitor {

        private Options options;
        private PageInfo pageInfo;
        private int textNodeCount = 0;
        private Node.TemplateText firstTextNode = null;
        private StringBuffer textBuffer;
        private final String emptyText = new String("");

        public TextCatVisitor(Compiler compiler) {
            options = compiler.getCompilationContext().getOptions();
            pageInfo = compiler.getPageInfo();
        }

        public void doVisit(Node n) throws JasperException {
            collectText();
        }

	/*
         * The following directis are ignored in text concatenation
         */

        public void visit(Node.PageDirective n) throws JasperException {
        }

        public void visit(Node.TagDirective n) throws JasperException {
        }

        public void visit(Node.TaglibDirective n) throws JasperException {
        }

        public void visit(Node.AttributeDirective n) throws JasperException {
        }

        public void visit(Node.VariableDirective n) throws JasperException {
        }

        /*
         * Don't concatenate text across body boundaries
         */
        public void visitBody(Node n) throws JasperException {
            super.visitBody(n);
            collectText();
        }

        public void visit(Node.TemplateText n) throws JasperException {
            if ((options.getTrimSpaces() || pageInfo.isTrimDirectiveWhitespaces()) 
                    && n.isAllSpace()) {
                n.setText(emptyText);
                return;
            }

            if (textNodeCount++ == 0) {
                firstTextNode = n;
                textBuffer = new StringBuffer(n.getText());
            } else {
                // Append text to text buffer
                textBuffer.append(n.getText());
                n.setText(emptyText);
            }
        }

        /**
         * This method breaks concatenation mode.  As a side effect it copies
         * the concatenated string to the first text node 
         */
        private void collectText() {

            if (textNodeCount > 1) {
                // Copy the text in buffer into the first template text node.
                firstTextNode.setText(textBuffer.toString());
            }
            textNodeCount = 0;
        }

    }

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

        TextCatVisitor v = new TextCatVisitor(compiler);
        page.visit(v);

	// Cleanup, in case the page ends with a template text
        v.collectText();
    }
}