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/*
 * Vaadin Framework 7
 *
 * 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.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import java.util.Vector;
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("serial")
public class JsonPaintTarget implements PaintTarget {

    /* Document type declarations */

    private final static String UIDL_ARG_NAME = "name";

    private final Stack mOpenTags;

    private final Stack openJsonTags;

    // these match each other element-wise
    private final Stack openPaintables;
    private final Stack 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
     * @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 Stack();
        openJsonTags = new Stack();

        openPaintables = new Stack();
        openPaintableTags = new Stack();

        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. * @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 tag * 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.size() > 0) { final JsonTag parent = openJsonTags.pop(); String lastTag = ""; 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. */ static public 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 */ static public 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()); } 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("\"" + name + "\":["); 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; Vector variables = new Vector(); Vector children = new Vector(); Vector attr = new Vector(); StringBuilder data = new StringBuilder(); public boolean childrenArrayOpen = false; private boolean childNode = false; private boolean tagClosed = false; public JsonTag(String tagName) { data.append("[\"" + tagName + "\""); } 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.size() == 0) { 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 implements Serializable { boolean value; public BooleanVariable(VariableOwner owner, String name, boolean v) { value = v; this.name = name; } @Override public String getJsonPresentation() { return "\"" + name + "\":" + (value == true ? "true" : "false"); } } class StringVariable extends Variable implements Serializable { 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 implements Serializable { 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 implements Serializable { 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 implements Serializable { 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 implements Serializable { 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 implements Serializable { 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()); } }