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com.vaadin.server.JsonPaintTarget Maven / Gradle / Ivy
/*
* Copyright (C) 2000-2024 Vaadin Ltd
*
* This program is available under Vaadin Commercial License and Service Terms.
*
* See for the full
* license.
*/
package com.vaadin.server;
import java.io.PrintWriter;
import java.io.Serializable;
import java.io.Writer;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Deque;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.vaadin.ui.Alignment;
import com.vaadin.ui.Component;
import com.vaadin.ui.CustomLayout;
/**
* User Interface Description Language Target.
*
* TODO document better: role of this class, UIDL format, attributes, variables,
* etc.
*
* @author Vaadin Ltd.
* @since 5.0
*/
@SuppressWarnings({ "deprecation", "serial" })
public class JsonPaintTarget implements PaintTarget {
/* Document type declarations */
private static final String UIDL_ARG_NAME = "name";
private final Deque mOpenTags;
private final Deque openJsonTags;
// these match each other element-wise
private final Deque openPaintables;
private final Deque openPaintableTags;
private final PrintWriter uidlBuffer;
private boolean closed = false;
private final LegacyCommunicationManager manager;
private int changes = 0;
private final Set usedResources = new HashSet<>();
private boolean customLayoutArgumentsOpen = false;
private JsonTag tag;
private boolean cacheEnabled = false;
private final Set> usedClientConnectors = new HashSet<>();
/**
* Creates a new JsonPaintTarget.
*
* @param manager
* communication manager
* @param outWriter
* A character-output stream.
* @param cachingRequired
* true if this is not a full repaint, i.e. caches are to be
* used.
* @throws PaintException
* if the paint operation failed.
*/
public JsonPaintTarget(LegacyCommunicationManager manager, Writer outWriter,
boolean cachingRequired) throws PaintException {
this.manager = manager;
// Sets the target for UIDL writing
uidlBuffer = new PrintWriter(outWriter);
// Initialize tag-writing
mOpenTags = new ArrayDeque<>();
openJsonTags = new ArrayDeque<>();
openPaintables = new ArrayDeque<>();
openPaintableTags = new ArrayDeque<>();
cacheEnabled = cachingRequired;
}
@Override
public void startTag(String tagName) throws PaintException {
startTag(tagName, false);
}
/**
* Prints the element start tag.
*
*
* Todo:
* Checking of input values
*
*
*
* @param tagName
* the name of the start tag.
* @param isChildNode
* {@code true} if child node, {@code false} otherwise
* @throws PaintException
* if the paint operation failed.
*
*/
public void startTag(String tagName, boolean isChildNode)
throws PaintException {
// In case of null data output nothing:
if (tagName == null) {
throw new NullPointerException();
}
// Ensures that the target is open
if (closed) {
throw new PaintException(
"Attempted to write to a closed PaintTarget.");
}
if (tag != null) {
openJsonTags.push(tag);
}
// Checks tagName and attributes here
mOpenTags.push(tagName);
tag = new JsonTag(tagName);
customLayoutArgumentsOpen = false;
}
/**
* Prints the element end tag.
*
* If the parent tag is closed before every child tag is closed an
* PaintException is raised.
*
* @param tagName
* the name of the end tag.
* @throws PaintException
* if the paint operation failed.
*/
@Override
public void endTag(String tagName) throws PaintException {
// In case of null data output nothing:
if (tagName == null) {
throw new NullPointerException();
}
// Ensure that the target is open
if (closed) {
throw new PaintException(
"Attempted to write to a closed PaintTarget.");
}
if (!openJsonTags.isEmpty()) {
final JsonTag parent = openJsonTags.pop();
String lastTag = mOpenTags.pop();
if (!tagName.equalsIgnoreCase(lastTag)) {
throw new PaintException("Invalid UIDL: wrong ending tag: '"
+ tagName + "' expected: '" + lastTag + "'.");
}
parent.addData(tag.getJSON());
tag = parent;
} else {
changes++;
uidlBuffer.print(((changes > 1) ? "," : "") + tag.getJSON());
tag = null;
}
}
/**
* Substitutes the XML sensitive characters with predefined XML entities.
*
* @param xml
* the String to be substituted.
* @return A new string instance where all occurrences of XML sensitive
* characters are substituted with entities.
*/
public static String escapeXML(String xml) {
if (xml == null || xml.length() <= 0) {
return "";
}
return escapeXML(new StringBuilder(xml)).toString();
}
/**
* Substitutes the XML sensitive characters with predefined XML entities.
*
* @param xml
* the String to be substituted.
* @return A new StringBuilder instance where all occurrences of XML
* sensitive characters are substituted with entities.
*
*/
static StringBuilder escapeXML(StringBuilder xml) {
if (xml == null || xml.length() <= 0) {
return new StringBuilder();
}
final StringBuilder result = new StringBuilder(xml.length() * 2);
for (int i = 0; i < xml.length(); i++) {
final char c = xml.charAt(i);
final String s = toXmlChar(c);
if (s != null) {
result.append(s);
} else {
result.append(c);
}
}
return result;
}
/**
* Escapes the given string so it can safely be used as a JSON string.
*
* @param s
* The string to escape
* @return Escaped version of the string
*/
public static String escapeJSON(String s) {
// FIXME: Move this method to another class as other classes use it
// also.
if (s == null) {
return "";
}
final StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
final char ch = s.charAt(i);
switch (ch) {
case '"':
sb.append("\\\"");
break;
case '\\':
sb.append("\\\\");
break;
case '\b':
sb.append("\\b");
break;
case '\f':
sb.append("\\f");
break;
case '\n':
sb.append("\\n");
break;
case '\r':
sb.append("\\r");
break;
case '\t':
sb.append("\\t");
break;
case '/':
sb.append("\\/");
break;
default:
if (ch >= '\u0000' && ch <= '\u001F') {
final String ss = Integer.toHexString(ch);
sb.append("\\u");
for (int k = 0; k < 4 - ss.length(); k++) {
sb.append('0');
}
sb.append(ss.toUpperCase(Locale.ROOT));
} else {
sb.append(ch);
}
}
}
return sb.toString();
}
/**
* Substitutes a XML sensitive character with predefined XML entity.
*
* @param c
* the Character to be replaced with an entity.
* @return String of the entity or null if character is not to be replaced
* with an entity.
*/
private static String toXmlChar(char c) {
switch (c) {
case '&':
return "&"; // & => &
case '>':
return ">"; // > => >
case '<':
return "<"; // < => <
case '"':
return """; // " => "
case '\'':
return "'"; // ' => '
default:
return null;
}
}
/**
* Prints XML-escaped text.
*
* @param str
* @throws PaintException
* if the paint operation failed.
*
*/
@Override
public void addText(String str) throws PaintException {
tag.addData("\"" + escapeJSON(str) + "\"");
}
@Override
public void addAttribute(String name, boolean value) throws PaintException {
tag.addAttribute("\"" + name + "\":" + (value ? "true" : "false"));
}
@Override
public void addAttribute(String name, Resource value)
throws PaintException {
if (value == null) {
throw new NullPointerException();
}
ClientConnector ownerConnector = openPaintables.peek();
ownerConnector.getUI().getSession().getGlobalResourceHandler(true)
.register(value, ownerConnector);
ResourceReference reference = ResourceReference.create(value,
ownerConnector, name);
addAttribute(name, reference.getURL());
}
@Override
public void addAttribute(String name, int value) throws PaintException {
tag.addAttribute("\"" + name + "\":" + String.valueOf(value));
}
@Override
public void addAttribute(String name, long value) throws PaintException {
tag.addAttribute("\"" + name + "\":" + String.valueOf(value));
}
@Override
public void addAttribute(String name, float value) throws PaintException {
tag.addAttribute("\"" + name + "\":" + String.valueOf(value));
}
@Override
public void addAttribute(String name, double value) throws PaintException {
tag.addAttribute("\"" + name + "\":" + String.valueOf(value));
}
@Override
public void addAttribute(String name, String value) throws PaintException {
// In case of null data output nothing:
if ((value == null) || (name == null)) {
throw new NullPointerException(
"Parameters must be non-null strings");
}
tag.addAttribute("\"" + name + "\":\"" + escapeJSON(value) + "\"");
if (customLayoutArgumentsOpen && "template".equals(name)) {
getUsedResources().add("layouts/" + value + ".html");
}
}
@Override
public void addAttribute(String name, Component value)
throws PaintException {
final String id = value.getConnectorId();
addAttribute(name, id);
}
@Override
public void addAttribute(String name, Map value)
throws PaintException {
StringBuilder sb = new StringBuilder();
sb.append("\"");
sb.append(name);
sb.append("\":");
sb.append('{');
for (Iterator it = value.keySet().iterator(); it.hasNext();) {
Object key = it.next();
Object mapValue = value.get(key);
sb.append("\"");
if (key instanceof ClientConnector) {
sb.append(((ClientConnector) key).getConnectorId());
} else {
sb.append(escapeJSON(key.toString()));
}
sb.append("\":");
if (mapValue instanceof Float || mapValue instanceof Integer
|| mapValue instanceof Double || mapValue instanceof Boolean
|| mapValue instanceof Alignment) {
sb.append(mapValue);
} else {
sb.append("\"");
sb.append(escapeJSON(mapValue.toString()));
sb.append("\"");
}
if (it.hasNext()) {
sb.append(',');
}
}
sb.append('}');
tag.addAttribute(sb.toString());
}
@Override
public void addAttribute(String name, Object[] values) {
// In case of null data output nothing:
if ((values == null) || (name == null)) {
throw new NullPointerException(
"Parameters must be non-null strings");
}
final StringBuilder buf = new StringBuilder();
buf.append("\"").append(name).append("\":[");
for (int i = 0; i < values.length; i++) {
if (i > 0) {
buf.append(',');
}
buf.append("\"");
buf.append(escapeJSON(values[i].toString()));
buf.append("\"");
}
buf.append(']');
tag.addAttribute(buf.toString());
}
@Override
public void addVariable(VariableOwner owner, String name, String value)
throws PaintException {
tag.addVariable(new StringVariable(owner, name, escapeJSON(value)));
}
@Override
public void addVariable(VariableOwner owner, String name, Component value)
throws PaintException {
tag.addVariable(
new StringVariable(owner, name, value.getConnectorId()));
}
@Override
public void addVariable(VariableOwner owner, String name, int value)
throws PaintException {
tag.addVariable(new IntVariable(owner, name, value));
}
@Override
public void addVariable(VariableOwner owner, String name, long value)
throws PaintException {
tag.addVariable(new LongVariable(owner, name, value));
}
@Override
public void addVariable(VariableOwner owner, String name, float value)
throws PaintException {
tag.addVariable(new FloatVariable(owner, name, value));
}
@Override
public void addVariable(VariableOwner owner, String name, double value)
throws PaintException {
tag.addVariable(new DoubleVariable(owner, name, value));
}
@Override
public void addVariable(VariableOwner owner, String name, boolean value)
throws PaintException {
tag.addVariable(new BooleanVariable(owner, name, value));
}
@Override
public void addVariable(VariableOwner owner, String name, String[] value)
throws PaintException {
tag.addVariable(new ArrayVariable(owner, name, value));
}
/**
* Adds a upload stream type variable.
*
* TODO not converted for JSON
*
* @param owner
* the Listener for variable changes.
* @param name
* the Variable name.
*
* @throws PaintException
* if the paint operation failed.
*/
@Override
public void addUploadStreamVariable(VariableOwner owner, String name)
throws PaintException {
startTag("uploadstream");
addAttribute(UIDL_ARG_NAME, name);
endTag("uploadstream");
}
/**
* Prints the single text section.
*
* Prints full text section. The section data is escaped
*
* @param sectionTagName
* the name of the tag.
* @param sectionData
* the section data to be printed.
* @throws PaintException
* if the paint operation failed.
*/
@Override
public void addSection(String sectionTagName, String sectionData)
throws PaintException {
tag.addData("{\"" + sectionTagName + "\":\"" + escapeJSON(sectionData)
+ "\"}");
}
/**
* Adds XML directly to UIDL.
*
* @param xml
* the Xml to be added.
* @throws PaintException
* if the paint operation failed.
*/
@Override
public void addUIDL(String xml) throws PaintException {
// Ensure that the target is open
if (closed) {
throw new PaintException(
"Attempted to write to a closed PaintTarget.");
}
// Make sure that the open start tag is closed before
// anything is written.
// Escape and write what was given
if (xml != null) {
tag.addData("\"" + escapeJSON(xml) + "\"");
}
}
/**
* Adds XML section with namespace.
*
* @param sectionTagName
* the name of the tag.
* @param sectionData
* the section data.
* @param namespace
* the namespace to be added.
* @throws PaintException
* if the paint operation failed.
*
* @see com.vaadin.server.PaintTarget#addXMLSection(String, String, String)
*/
@Override
public void addXMLSection(String sectionTagName, String sectionData,
String namespace) throws PaintException {
// Ensure that the target is open
if (closed) {
throw new PaintException(
"Attempted to write to a closed PaintTarget.");
}
startTag(sectionTagName);
if (namespace != null) {
addAttribute("xmlns", namespace);
}
if (sectionData != null) {
tag.addData("\"" + escapeJSON(sectionData) + "\"");
}
endTag(sectionTagName);
}
/**
* Gets the UIDL already printed to stream. Paint target must be closed
* before the getUIDL can be called.
*
* @return the UIDL.
*/
public String getUIDL() {
if (closed) {
return uidlBuffer.toString();
}
throw new IllegalStateException(
"Tried to read UIDL from open PaintTarget");
}
/**
* Closes the paint target. Paint target must be closed before the
* getUIDL can be called. Subsequent attempts to write to paint
* target. If the target was already closed, call to this function is
* ignored. will generate an exception.
*
* @throws PaintException
* if the paint operation failed.
*/
public void close() throws PaintException {
if (tag != null) {
uidlBuffer.write(tag.getJSON());
}
flush();
closed = true;
}
/**
* Method flush.
*/
private void flush() {
uidlBuffer.flush();
}
/*
* (non-Javadoc)
*
* @see com.vaadin.terminal.PaintTarget#startPaintable(com.vaadin.terminal
* .Paintable, java.lang.String)
*/
@Override
public PaintStatus startPaintable(Component connector, String tagName)
throws PaintException {
boolean topLevelPaintable = openPaintables.isEmpty();
if (getLogger().isLoggable(Level.FINE)) {
getLogger().log(Level.FINE, "startPaintable for {0}@{1}",
new Object[] { connector.getClass().getName(),
Integer.toHexString(connector.hashCode()) });
}
startTag(tagName, true);
openPaintables.push(connector);
openPaintableTags.push(tagName);
addAttribute("id", connector.getConnectorId());
// Only paint top level paintables. All sub paintables are marked as
// queued and painted separately later.
if (!topLevelPaintable) {
return PaintStatus.CACHED;
}
if (connector instanceof CustomLayout) {
customLayoutArgumentsOpen = true;
}
return PaintStatus.PAINTING;
}
@Override
public void endPaintable(Component paintable) throws PaintException {
if (getLogger().isLoggable(Level.FINE)) {
getLogger().log(Level.FINE, "endPaintable for {0}@{1}",
new Object[] { paintable.getClass().getName(),
Integer.toHexString(paintable.hashCode()) });
}
ClientConnector openPaintable = openPaintables.peek();
if (paintable != openPaintable) {
throw new PaintException("Invalid UIDL: closing wrong paintable: '"
+ paintable.getConnectorId() + "' expected: '"
+ openPaintable.getConnectorId() + "'.");
}
// remove paintable from the stack
openPaintables.pop();
String openTag = openPaintableTags.pop();
endTag(openTag);
}
/*
* (non-Javadoc)
*
* @see com.vaadin.terminal.PaintTarget#addCharacterData(java.lang.String )
*/
@Override
public void addCharacterData(String text) throws PaintException {
if (text != null) {
tag.addData(text);
}
}
/**
* This is basically a container for UI components variables, that will be
* added at the end of JSON object.
*
* @author mattitahvonen
*
*/
class JsonTag implements Serializable {
boolean firstField = false;
List variables = new ArrayList<>();
List children = new ArrayList<>();
List attr = new ArrayList<>();
StringBuilder data = new StringBuilder();
public boolean childrenArrayOpen = false;
private boolean childNode = false;
private boolean tagClosed = false;
public JsonTag(String tagName) {
data.append("[\"").append(tagName).append("\"");
}
private void closeTag() {
if (!tagClosed) {
data.append(attributesAsJsonObject());
data.append(getData());
// Writes the end (closing) tag
data.append(']');
tagClosed = true;
}
}
public String getJSON() {
if (!tagClosed) {
closeTag();
}
return data.toString();
}
public void openChildrenArray() {
if (!childrenArrayOpen) {
// append("c : [");
childrenArrayOpen = true;
// firstField = true;
}
}
public void closeChildrenArray() {
// append(']');
// firstField = false;
}
public void setChildNode(boolean b) {
childNode = b;
}
public boolean isChildNode() {
return childNode;
}
public String startField() {
if (firstField) {
firstField = false;
return "";
} else {
return ",";
}
}
/**
*
* @param s
* json string, object or array
*/
public void addData(String s) {
children.add(s);
}
public String getData() {
final StringBuilder buf = new StringBuilder();
final Iterator it = children.iterator();
while (it.hasNext()) {
buf.append(startField());
buf.append(it.next());
}
return buf.toString();
}
public void addAttribute(String jsonNode) {
attr.add(jsonNode);
}
private String attributesAsJsonObject() {
final StringBuilder buf = new StringBuilder();
buf.append(startField());
buf.append('{');
for (final Iterator iter = attr.iterator(); iter
.hasNext();) {
final String element = (String) iter.next();
buf.append(element);
if (iter.hasNext()) {
buf.append(',');
}
}
buf.append(tag.variablesAsJsonObject());
buf.append('}');
return buf.toString();
}
public void addVariable(Variable v) {
variables.add(v);
}
private String variablesAsJsonObject() {
if (variables.isEmpty()) {
return "";
}
final StringBuilder buf = new StringBuilder();
buf.append(startField());
buf.append("\"v\":{");
final Iterator iter = variables.iterator();
while (iter.hasNext()) {
final Variable element = (Variable) iter.next();
buf.append(element.getJsonPresentation());
if (iter.hasNext()) {
buf.append(',');
}
}
buf.append('}');
return buf.toString();
}
}
abstract class Variable implements Serializable {
String name;
public abstract String getJsonPresentation();
}
class BooleanVariable extends Variable {
boolean value;
public BooleanVariable(VariableOwner owner, String name, boolean v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":" + (value ? "true" : "false");
}
}
class StringVariable extends Variable {
String value;
public StringVariable(VariableOwner owner, String name, String v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":\"" + value + "\"";
}
}
class IntVariable extends Variable {
int value;
public IntVariable(VariableOwner owner, String name, int v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":" + value;
}
}
class LongVariable extends Variable {
long value;
public LongVariable(VariableOwner owner, String name, long v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":" + value;
}
}
class FloatVariable extends Variable {
float value;
public FloatVariable(VariableOwner owner, String name, float v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":" + value;
}
}
class DoubleVariable extends Variable {
double value;
public DoubleVariable(VariableOwner owner, String name, double v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
return "\"" + name + "\":" + value;
}
}
class ArrayVariable extends Variable {
String[] value;
public ArrayVariable(VariableOwner owner, String name, String[] v) {
value = v;
this.name = name;
}
@Override
public String getJsonPresentation() {
StringBuilder sb = new StringBuilder();
sb.append("\"");
sb.append(name);
sb.append("\":[");
for (int i = 0; i < value.length;) {
sb.append("\"");
sb.append(escapeJSON(value[i]));
sb.append("\"");
i++;
if (i < value.length) {
sb.append(',');
}
}
sb.append(']');
return sb.toString();
}
}
public Set getUsedResources() {
return usedResources;
}
@Override
@SuppressWarnings("unchecked")
public String getTag(ClientConnector clientConnector) {
Class clientConnectorClass = clientConnector
.getClass();
while (clientConnectorClass.isAnonymousClass()) {
clientConnectorClass = (Class) clientConnectorClass
.getSuperclass();
}
Class clazz = clientConnectorClass;
while (!usedClientConnectors.contains(clazz)
&& clazz.getSuperclass() != null
&& ClientConnector.class.isAssignableFrom(clazz)) {
usedClientConnectors.add((Class) clazz);
clazz = clazz.getSuperclass();
}
return manager.getTagForType(clientConnectorClass);
}
public Collection> getUsedClientConnectors() {
return usedClientConnectors;
}
@Override
public void addVariable(VariableOwner owner, String name,
StreamVariable value) throws PaintException {
String url = manager.getStreamVariableTargetUrl((ClientConnector) owner,
name, value);
if (url != null) {
addVariable(owner, name, url);
} // else { //NOP this was just a cleanup by component }
}
/*
* (non-Javadoc)
*
* @see com.vaadin.terminal.PaintTarget#isFullRepaint()
*/
@Override
public boolean isFullRepaint() {
return !cacheEnabled;
}
private static final Logger getLogger() {
return Logger.getLogger(JsonPaintTarget.class.getName());
}
}
