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/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.text.templates;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * The template translator translates a string into a template buffer. Regions marked as variables
 * are translated into TemplateVariables.
 * 

* The EBNF grammar of a valid string is as follows: *

*
 template := (text | escape)*.
 * text := character - dollar.
 * escape := dollar ('{' variable '}' | dollar).
 * dollar := '$'.
 * variable := identifier | identifier ':' type.
 * type := qualifiedname | qualifiedname '(' arguments ')'.
 * arguments := (argument ',')* argument.
 * argument := qualifiedname | argumenttext.
 * qualifiedname := (identifier '.')* identifier.
 * argumenttext := "'" (character - "'" | "'" "'")* "'".
 * identifier := javaidentifierpart - "$".
*

* Clients may only replace the createVariable method of this class. *

* * @since 3.0 */ public class TemplateTranslator { /** * Regex pattern for identifier. * Note: For historic reasons, this pattern allows numbers at the beginning of an identifier. * @since 3.7 */ private static final String IDENTIFIER= "(?:[\\p{javaJavaIdentifierPart}&&[^\\$]]++)"; //$NON-NLS-1$ /** * Regex pattern for qualifiedname * @since 3.4 */ private static final String QUALIFIED_NAME= "(?:" + IDENTIFIER + "\\.)*+" + IDENTIFIER; //$NON-NLS-1$ //$NON-NLS-2$ /** * Regex pattern for argumenttext * @since 3.4 */ private static final String ARGUMENT_TEXT= "'(?:(?:'')|(?:[^']))*+'"; //$NON-NLS-1$ /** * Regex pattern for argument * @since 3.4 */ private static final String ARGUMENT= "(?:" + QUALIFIED_NAME + ")|(?:" + ARGUMENT_TEXT + ")"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ /** * Regex pattern for whitespace * @since 3.5 */ private static final String SPACES= "\\s*+"; //$NON-NLS-1$ /** * Precompiled regex pattern for qualified names. * @since 3.3 */ private static final Pattern PARAM_PATTERN= Pattern.compile(ARGUMENT); /** * Precompiled regex pattern for valid dollar escapes (dollar literals and variables) and * (invalid) single dollars. * @since 3.3 */ private static final Pattern ESCAPE_PATTERN= Pattern.compile( "\\$\\$|\\$\\{" + // $$|${ //$NON-NLS-1$ SPACES + "(" + IDENTIFIER + "?+)" + // variable id group (1) //$NON-NLS-1$ //$NON-NLS-2$ SPACES + "(?:" + //$NON-NLS-1$ ":" + //$NON-NLS-1$ SPACES + "(" + QUALIFIED_NAME + ")" + // variable type group (2) //$NON-NLS-1$ //$NON-NLS-2$ SPACES + "(?:" + //$NON-NLS-1$ "\\(" + // ( //$NON-NLS-1$ SPACES + "((?:(?:" + ARGUMENT + ")" + SPACES + "," + SPACES + ")*+(?:" + ARGUMENT + "))" + // arguments group (3) //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ SPACES + "\\)" + // ) //$NON-NLS-1$ ")?" + //$NON-NLS-1$ SPACES + ")?" + //$NON-NLS-1$ "\\}|\\$"); // }|$ //$NON-NLS-1$ /** * @since 3.3 */ private final class VariableDescription { final List fOffsets= new ArrayList(5); final String fName; TemplateVariableType fType; VariableDescription(String name, TemplateVariableType type) { fName= name; fType= type; } void mergeType(TemplateVariableType type) throws TemplateException { if (type == null) return; if (fType == null) fType= type; if (!type.equals(fType)) fail(TextTemplateMessages.getFormattedString("TemplateTranslator.error.incompatible.type", fName)); //$NON-NLS-1$ } } /** Last translation error. */ private String fErrorMessage; /** * Used to ensure compatibility with subclasses overriding * {@link #createVariable(String, String, int[])}. * @since 3.3 */ private TemplateVariableType fCurrentType; /** * Returns an error message if an error occurred for the last translation, null * otherwise. * * @return the error message if an error occurred during the most recent translation, * null otherwise */ public String getErrorMessage() { return fErrorMessage; } /** * Translates a template to a TemplateBuffer. null is returned if * there was an error. getErrorMessage() retrieves the associated error message. * * @param template the template to translate. * @return returns the template buffer corresponding to the string * @see #getErrorMessage() * @throws TemplateException if translation failed */ public TemplateBuffer translate(Template template) throws TemplateException { return parse(template.getPattern()); } /** * Translates a template string to TemplateBuffer. null is * returned if there was an error. getErrorMessage() retrieves the associated * error message. * * @param string the string to translate. * @return returns the template buffer corresponding to the string * @see #getErrorMessage() * @throws TemplateException if translation failed */ public TemplateBuffer translate(String string) throws TemplateException { return parse(string); } /** * Internal parser. * * @param string the string to parse * @return the parsed TemplateBuffer * @throws TemplateException if the string does not conform to the template format */ private TemplateBuffer parse(String string) throws TemplateException { fErrorMessage= null; final StringBuffer buffer= new StringBuffer(string.length()); final Matcher matcher= ESCAPE_PATTERN.matcher(string); final Map variables= new LinkedHashMap(); int complete= 0; while (matcher.find()) { // append any verbatim text buffer.append(string.substring(complete, matcher.start())); // check the escaped sequence if ("$".equals(matcher.group())) { //$NON-NLS-1$ fail(TextTemplateMessages.getString("TemplateTranslator.error.incomplete.variable")); //$NON-NLS-1$ } else if ("$$".equals(matcher.group())) { //$NON-NLS-1$ // escaped $ buffer.append('$'); } else { // parse variable String name= matcher.group(1); String typeName= matcher.group(2); String params= matcher.group(3); TemplateVariableType type= createType(typeName, params); updateOrCreateVariable(variables, name, type, buffer.length()); buffer.append(name); } complete= matcher.end(); } // append remaining verbatim text buffer.append(string.substring(complete)); TemplateVariable[] vars= createVariables(variables); return new TemplateBuffer(buffer.toString(), vars); } private TemplateVariableType createType(String typeName, String paramString) { if (typeName == null) return null; if (paramString == null) return new TemplateVariableType(typeName); final Matcher matcher= PARAM_PATTERN.matcher(paramString); List params= new ArrayList(5); while (matcher.find()) { String argument= matcher.group(); if (argument.charAt(0) == '\'') { // argumentText argument= argument.substring(1, argument.length() - 1).replaceAll("''", "'"); //$NON-NLS-1$ //$NON-NLS-2$ } params.add(argument); } return new TemplateVariableType(typeName, (String[]) params.toArray(new String[params.size()])); } private void fail(String message) throws TemplateException { fErrorMessage= message; throw new TemplateException(message); } /** * If there is no variable named name, a new variable with the given type, name * and offset is created. If one exists, the offset is added to the variable and the type is * merged with the existing type. * * @param variables the variables by variable name * @param name the name of the variable * @param type the variable type, null for not defined * @param offset the buffer offset of the variable * @throws TemplateException if merging the type fails * @since 3.3 */ private void updateOrCreateVariable(Map variables, String name, TemplateVariableType type, int offset) throws TemplateException { VariableDescription varDesc= (VariableDescription) variables.get(name); if (varDesc == null) { varDesc= new VariableDescription(name, type); variables.put(name, varDesc); } else { varDesc.mergeType(type); } varDesc.fOffsets.add(new Integer(offset)); } /** * Creates proper {@link TemplateVariable}s from the variable descriptions. * * @param variables the variable descriptions by variable name * @return the corresponding variables * @since 3.3 */ private TemplateVariable[] createVariables(Map variables) { TemplateVariable[] result= new TemplateVariable[variables.size()]; int idx= 0; for (Iterator it= variables.values().iterator(); it.hasNext(); idx++) { VariableDescription desc= (VariableDescription) it.next(); TemplateVariableType type= desc.fType == null ? new TemplateVariableType(desc.fName) : desc.fType; int[] offsets= new int[desc.fOffsets.size()]; int i= 0; for (Iterator intIt= desc.fOffsets.iterator(); intIt.hasNext(); i++) { Integer offset= (Integer) intIt.next(); offsets[i]= offset.intValue(); } fCurrentType= type; /* * Call the deprecated version of createVariable. When not overridden, it will delegate * to the new version using fCurrentType. */ TemplateVariable var= createVariable(type.getName(), desc.fName, offsets); result[idx]= var; } fCurrentType= null; // avoid dangling reference return result; } /** * Hook method to create new variables. Subclasses may override to supply their custom variable * type. *

* Clients may replace this method. *

* * @param type the type of the new variable. * @param name the name of the new variable. * @param offsets the offsets where the variable occurs in the template * @return a new instance of TemplateVariable * @deprecated as of 3.3 use {@link #createVariable(TemplateVariableType, String, int[])} instead */ protected TemplateVariable createVariable(String type, String name, int[] offsets) { return createVariable(fCurrentType, name, offsets); } /** * Hook method to create new variables. Subclasses may override to supply their custom variable * type. *

* Clients may replace this method. *

* * @param type the type of the new variable. * @param name the name of the new variable. * @param offsets the offsets where the variable occurs in the template * @return a new instance of TemplateVariable * @since 3.3 */ protected TemplateVariable createVariable(TemplateVariableType type, String name, int[] offsets) { return new TemplateVariable(type, name, name, offsets); } }




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