com.google.gwt.dev.codeserver.HtmlWriter Maven / Gradle / Ivy
/*
* Copyright 2012 Google Inc.
*
* 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 com.google.gwt.dev.codeserver;
import java.io.IOException;
import java.io.Writer;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
/**
* Writes HTML to a stream.
*/
class HtmlWriter {
private static final Set ALLOWED_TAGS =
Collections.unmodifiableSet(new HashSet(Arrays.asList(
"html", "head", "title", "style",
"body", "h1", "h2", "h3", "h4", "h5", "h6", "p", "a", "pre", "span",
"table", "tr", "td")));
private static final Set ALLOWED_ATTS =
Collections.unmodifiableSet(new HashSet(Arrays.asList(
"class=", "href=")));
private final Writer out;
HtmlWriter(Writer out) {
this.out = out;
}
HtmlWriter startTag(String tag) throws IOException {
checkTag(tag);
out.write('<');
out.write(tag);
out.write('>');
return this;
}
HtmlWriter startTag(String tag, String att, String value) throws IOException {
checkTag(tag);
out.write('<');
out.write(tag);
writeAtt(att, value);
out.write('>');
return this;
}
HtmlWriter endTag(String tag) throws IOException {
checkTag(tag);
out.write("');
return this;
}
/**
* Writes plain text (escaped).
*/
HtmlWriter text(String plainText) throws IOException {
for (char c : plainText.toCharArray()) {
text(c);
}
return this;
}
/**
* Writes plain text (escaped).
*/
void text(char c) throws IOException {
switch(c) {
case '<':
out.write("<");
break;
case '>':
out.write(">");
break;
case '&':
out.write("&");
break;
case '"':
out.write(""");
break;
default:
out.write(c);
}
}
/**
* Writes a newline.
*/
void nl() throws IOException {
out.append('\n');
}
private void writeAtt(String att, String value) throws IOException {
checkAtt(att);
out.write(' ');
out.write(att);
out.write('"');
text(value);
out.write('"');
}
private void checkTag(String tag) {
if (!ALLOWED_TAGS.contains(tag)) {
throw new IllegalArgumentException("unknown tag: " + tag);
}
}
private void checkAtt(String att) {
if (!ALLOWED_ATTS.contains(att)) {
throw new IllegalArgumentException("unknown att: " + att);
}
}
}