/**
* 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.hadoop.yarn.webapp.hamlet;
import com.google.common.base.Joiner;
import static com.google.common.base.Preconditions.*;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import java.io.PrintWriter;
import java.util.EnumSet;
import static java.util.EnumSet.*;
import java.util.Iterator;
import static org.apache.commons.lang.StringEscapeUtils.*;
import static org.apache.hadoop.yarn.webapp.hamlet.HamletImpl.EOpt.*;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.yarn.webapp.SubView;
import org.apache.hadoop.yarn.webapp.WebAppException;
/**
* A simple unbuffered generic hamlet implementation.
*
* Zero copy but allocation on every element, which could be
* optimized to use a thread-local element pool.
*
* Prints HTML as it builds. So the order is important.
*/
@InterfaceAudience.Private
public class HamletImpl extends HamletSpec {
private static final String INDENT_CHARS = " ";
private static final Splitter SS = Splitter.on('.').
omitEmptyStrings().trimResults();
private static final Joiner SJ = Joiner.on(' ');
private static final Joiner CJ = Joiner.on(", ");
static final int S_ID = 0;
static final int S_CLASS = 1;
int nestLevel;
int indents; // number of indent() called. mostly for testing.
private final PrintWriter out;
private final StringBuilder sb = new StringBuilder(); // not shared
private boolean wasInline = false;
/**
* Element options. (whether it needs end tag, is inline etc.)
*/
public enum EOpt {
/** needs end(close) tag */
ENDTAG,
/** The content is inline */
INLINE,
/** The content is preformatted */
PRE
};
/**
* The base class for elements
* @param <T> type of the parent (containing) element for the element
*/
public class EImp<T extends _> implements _Child {
private final String name;
private final T parent; // short cut for parent element
private final EnumSet<EOpt> opts; // element options
private boolean started = false;
private boolean attrsClosed = false;
EImp(String name, T parent, EnumSet<EOpt> opts) {
this.name = name;
this.parent = parent;
this.opts = opts;
}
@Override
public T _() {
closeAttrs();
--nestLevel;
printEndTag(name, opts);
return parent;
}
protected void _p(boolean quote, Object... args) {
closeAttrs();
for (Object s : args) {
if (!opts.contains(PRE)) {
indent(opts);
}
out.print(quote ? escapeHtml(String.valueOf(s))
: String.valueOf(s));
if (!opts.contains(INLINE) && !opts.contains(PRE)) {
out.println();
}
}
}
protected void _v(Class<? extends SubView> cls) {
closeAttrs();
subView(cls);
}
protected void closeAttrs() {
if (!attrsClosed) {
startIfNeeded();
++nestLevel;
out.print('>');
if (!opts.contains(INLINE) && !opts.contains(PRE)) {
out.println();
}
attrsClosed = true;
}
}
protected void addAttr(String name, String value) {
checkState(!attrsClosed, "attribute added after content");
startIfNeeded();
printAttr(name, value);
}
protected void addAttr(String name, Object value) {
addAttr(name, String.valueOf(value));
}
protected void addMediaAttr(String name, EnumSet<Media> media) {
// 6.13 comma-separated list
addAttr(name, CJ.join(media));
}
protected void addRelAttr(String name, EnumSet<LinkType> types) {
// 6.12 space-separated list
addAttr(name, SJ.join(types));
}
private void startIfNeeded() {
if (!started) {
printStartTag(name, opts);
started = true;
}
}
protected void _inline(boolean choice) {
if (choice) {
opts.add(INLINE);
} else {
opts.remove(INLINE);
}
}
protected void _endTag(boolean choice) {
if (choice) {
opts.add(ENDTAG);
} else {
opts.remove(ENDTAG);
}
}
protected void _pre(boolean choice) {
if (choice) {
opts.add(PRE);
} else {
opts.remove(PRE);
}
}
}
public class Generic<T extends _> extends EImp<T> implements PCData {
Generic(String name, T parent, EnumSet<EOpt> opts) {
super(name, parent, opts);
}
public Generic<T> _inline() {
super._inline(true);
return this;
}
public Generic<T> _noEndTag() {
super._endTag(false);
return this;
}
public Generic<T> _pre() {
super._pre(true);
return this;
}
public Generic<T> _attr(String name, String value) {
addAttr(name, value);
return this;
}
public Generic<Generic<T>> _elem(String name, EnumSet<EOpt> opts) {
closeAttrs();
return new Generic<Generic<T>>(name, this, opts);
}
public Generic<Generic<T>> elem(String name) {
return _elem(name, of(ENDTAG));
}
@Override
public Generic<T> _(Object... lines) {
_p(true, lines);
return this;
}
@Override
public Generic<T> _r(Object... lines) {
_p(false, lines);
return this;
}
}
public HamletImpl(PrintWriter out, int nestLevel, boolean wasInline) {
this.out = out;
this.nestLevel = nestLevel;
this.wasInline = wasInline;
}
public int nestLevel() {
return nestLevel;
}
public boolean wasInline() {
return wasInline;
}
public void setWasInline(boolean state) {
wasInline = state;
}
public PrintWriter getWriter() {
return out;
}
/**
* Create a root-level generic element.
* Mostly for testing purpose.
* @param <T> type of the parent element
* @param name of the element
* @param opts {@link EOpt element options}
* @return the element
*/
public <T extends _>
Generic<T> root(String name, EnumSet<EOpt> opts) {
return new Generic<T>(name, null, opts);
}
public <T extends _> Generic<T> root(String name) {
return root(name, of(ENDTAG));
}
protected void printStartTag(String name, EnumSet<EOpt> opts) {
indent(opts);
sb.setLength(0);
out.print(sb.append('<').append(name).toString()); // for easier mock test
}
protected void indent(EnumSet<EOpt> opts) {
if (opts.contains(INLINE) && wasInline) {
return;
}
if (wasInline) {
out.println();
}
wasInline = opts.contains(INLINE) || opts.contains(PRE);
for (int i = 0; i < nestLevel; ++i) {
out.print(INDENT_CHARS);
}
++indents;
}
protected void printEndTag(String name, EnumSet<EOpt> opts) {
if (!opts.contains(ENDTAG)) {
return;
}
if (!opts.contains(PRE)) {
indent(opts);
} else {
wasInline = opts.contains(INLINE);
}
sb.setLength(0);
out.print(sb.append("</").append(name).append('>').toString()); // ditto
if (!opts.contains(INLINE)) {
out.println();
}
}
protected void printAttr(String name, String value) {
sb.setLength(0);
sb.append(' ').append(name);
if (value != null) {
sb.append("=\"").append(escapeHtml(value)).append("\"");
}
out.print(sb.toString());
}
/**
* Sub-classes should override this to do something interesting.
* @param cls the sub-view class
*/
protected void subView(Class<? extends SubView> cls) {
indent(of(ENDTAG)); // not an inline view
sb.setLength(0);
out.print(sb.append('[').append(cls.getName()).append(']').toString());
out.println();
}
/**
* Parse selector into id and classes
* @param selector in the form of (#id)?(.class)*
* @return an two element array [id, "space-separated classes"].
* Either element could be null.
* @throws WebAppException when both are null or syntax error.
*/
public static String[] parseSelector(String selector) {
String[] result = new String[]{null, null};
Iterable<String> rs = SS.split(selector);
Iterator<String> it = rs.iterator();
if (it.hasNext()) {
String maybeId = it.next();
if (maybeId.charAt(0) == '#') {
result[S_ID] = maybeId.substring(1);
if (it.hasNext()) {
result[S_CLASS] = SJ.join(Iterables.skip(rs, 1));
}
} else {
result[S_CLASS] = SJ.join(rs);
}
return result;
}
throw new WebAppException("Error parsing selector: "+ selector);
}
/**
* Set id and/or class attributes for an element.
* @param <E> type of the element
* @param e the element
* @param selector Haml form of "(#id)?(.class)*"
* @return the element
*/
public static <E extends CoreAttrs> E setSelector(E e, String selector) {
String[] res = parseSelector(selector);
if (res[S_ID] != null) {
e.$id(res[S_ID]);
}
if (res[S_CLASS] != null) {
e.$class(res[S_CLASS]);
}
return e;
}
public static <E extends LINK> E setLinkHref(E e, String href) {
if (href.endsWith(".css")) {
e.$rel("stylesheet"); // required in html5
}
e.$href(href);
return e;
}
public static <E extends SCRIPT> E setScriptSrc(E e, String src) {
if (src.endsWith(".js")) {
e.$type("text/javascript"); // required in html4
}
e.$src(src);
return e;
}
}