org.apache.jasper.compiler.TextOptimizer Maven / Gradle / Ivy
/*
* 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.jasper.compiler;
import org.apache.jasper.JasperException;
import org.apache.jasper.Options;
import org.apache.jasper.TrimSpacesOption;
/**
*/
public class TextOptimizer {
/**
* A visitor to concatenate contiguous template texts.
*/
private static class TextCatVisitor extends Node.Visitor {
private static final String EMPTY_TEXT = "";
private static final String SINGLE_SPACE = " ";
private final Options options;
private final PageInfo pageInfo;
private int textNodeCount = 0;
private Node.TemplateText firstTextNode = null;
private StringBuilder textBuffer;
public TextCatVisitor(Compiler compiler) {
options = compiler.getCompilationContext().getOptions();
pageInfo = compiler.getPageInfo();
}
@Override
public void doVisit(Node n) throws JasperException {
collectText();
}
/*
* The following directives are ignored in text concatenation
*/
@Override
public void visit(Node.PageDirective n) throws JasperException {
}
@Override
public void visit(Node.TagDirective n) throws JasperException {
}
@Override
public void visit(Node.TaglibDirective n) throws JasperException {
}
@Override
public void visit(Node.AttributeDirective n) throws JasperException {
}
@Override
public void visit(Node.VariableDirective n) throws JasperException {
}
/*
* Don't concatenate text across body boundaries
*/
@Override
public void visitBody(Node n) throws JasperException {
super.visitBody(n);
collectText();
}
@Override
public void visit(Node.TemplateText n) throws JasperException {
if (n.isAllSpace()) {
if ((options.getTrimSpaces() == TrimSpacesOption.TRUE ||
pageInfo.isTrimDirectiveWhitespaces())) {
n.setText(EMPTY_TEXT);
return;
} else if (options.getTrimSpaces() == TrimSpacesOption.SINGLE) {
n.setText(SINGLE_SPACE);
return;
}
}
if (textNodeCount++ == 0) {
firstTextNode = n;
textBuffer = new StringBuilder(n.getText());
} else {
// Append text to text buffer
textBuffer.append(n.getText());
n.setText(EMPTY_TEXT);
}
}
/**
* 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();
}
}