Java tutorial
/* * The contents of this file are subject to the Mozilla Public * License Version 1.1 (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.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is Content Registry 3 * * The Initial Owner of the Original Code is European Environment * Agency. Portions created by Zero Technologies are Copyright * (C) European Environment Agency. All Rights Reserved. * * Contributor(s): * Jaanus Heinlaid */ package eionet.cr.web.action.admin.postHarvest; import java.util.ArrayList; import java.util.Collection; import java.util.StringTokenizer; import org.apache.commons.lang.StringUtils; /** * * @author Jaanus Heinlaid */ public final class PostHarvestScriptParser { /** */ public static final int TEST_RESULTS_LIMIT = 500; /** */ public static final String HARVESTED_SOURCE_VARIABLE = "harvestedSource"; public static final String ASSOCIATED_TYPE_VARIABLE = "thisType"; /** * Hide utility class constructor. */ private PostHarvestScriptParser() { // Just an empty private constructor to avoid instantiating this utility class. } /** * * @param script * @param harvestedSource * @param associatedType * @return */ public static String parseForExecution(String script, String harvestedSource, String associatedType) { if (StringUtils.isBlank(script)) { return script; } if (!StringUtils.isBlank(harvestedSource)) { script = StringUtils.replace(script, "?" + HARVESTED_SOURCE_VARIABLE, "<" + harvestedSource + ">"); } if (!StringUtils.isBlank(associatedType)) { script = StringUtils.replace(script, "?" + ASSOCIATED_TYPE_VARIABLE, "<" + associatedType + ">"); } return script; } /** * * @param script * @param graphUri * @return */ public static String deriveSelect(String script, String graphUri) { String result = script; if (containsToken(result, "DELETE")) { if (containsToken(result, "INSERT")) { result = substringBeforeToken(result, "DELETE") + "SELECT" + substringAfterToken(result, "INSERT"); } else { result = substringBeforeToken(result, "DELETE") + "SELECT" + substringAfterToken(result, "DELETE"); } } else if (containsToken(result, "INSERT")) { result = substringBeforeToken(result, "INSERT") + "SELECT" + substringAfterToken(result, "INSERT"); } if (containsToken(result, "WHERE")) { if (!containsToken(result, "FROM")) { result = substringBeforeToken(result, "WHERE") + "FROM <" + graphUri + "> WHERE" + substringAfterToken(result, "WHERE"); } } else { result = result + " FROM <" + graphUri + "> WHERE {?s ?p ?o}"; } if (containsToken(result, "LIMIT")) { result = substringBeforeToken(result, "LIMIT") + "LIMIT " + TEST_RESULTS_LIMIT; } else { result = result + " LIMIT " + TEST_RESULTS_LIMIT; } if (containsToken(result, "SELECT")) { String afterSelect = substringAfterToken(result, "SELECT"); afterSelect = StringUtils.replaceOnce(afterSelect, "{", ""); afterSelect = StringUtils.replaceOnce(afterSelect, "}", ""); result = substringBeforeToken(result, "SELECT") + "SELECT" + afterSelect; } return result.trim(); } /** * * @param script * @param harvestedSource * @param associatedType * @return * @throws ScriptParseException */ public static String deriveConstruct(String script, String harvestedSource, String associatedType) throws ScriptParseException { if (script == null || StringUtils.isBlank(script)) { return script; } String result = script; if (containsToken(script, "MODIFY")) { result = deriveConstructFromModify(script); } else if (containsToken(script, "DELETE")) { result = deriveConstructFromDelete(script); } else if (containsToken(script, "INSERT")) { result = deriveConstructFromInsert(script); } if (result != null && !StringUtils.isBlank(harvestedSource)) { result = replaceToken(result, "?" + HARVESTED_SOURCE_VARIABLE, "<" + harvestedSource + ">"); } if (result != null && !StringUtils.isBlank(associatedType)) { result = replaceToken(result, "?" + ASSOCIATED_TYPE_VARIABLE, "<" + associatedType + ">"); } return result == null ? null : result.trim(); } /** * * @param script * @return * @throws ScriptParseException */ private static String deriveConstructFromModify(String script) throws ScriptParseException { String datasetClause = null; String constructTemplate = null; String wherePattern = null; // Ensure this is a valid MODIFY statement. if (!containsToken(script, "DELETE")) { throw new ScriptParseException("Expecting MODIFY statement to contain DELETE!"); } else if (!containsToken(substringAfterToken(script, "DELETE"), "INSERT")) { throw new ScriptParseException("Expecting MODIFY statement to contain DELETE and INSERT!"); } // Prepare some helpful variables. String afterInsert = substringAfterToken(script, "INSERT"); boolean datasetSpecified = containsToken(afterInsert, "FROM"); boolean wherePatternSpecified = containsToken(afterInsert, "WHERE"); // Extract the CONSTRUCT template, and dataset part if specified. if (datasetSpecified) { constructTemplate = substringBeforeToken(afterInsert, "FROM"); if (wherePatternSpecified) { datasetClause = substringBetweenTokens(afterInsert, "FROM", "WHERE"); } else { datasetClause = substringAfterToken(afterInsert, "FROM"); } } else if (wherePatternSpecified) { constructTemplate = substringBeforeToken(afterInsert, "WHERE"); } else { constructTemplate = afterInsert; } // Ensure CONSTRUCT template is not blank and starts-ends with curly braces. if (constructTemplate == null || !startsEndsWith(constructTemplate.trim(), "{", "}")) { throw new ScriptParseException("Could not detect CONSTRUCT template!"); } // Extract WHERE pattern if present. if (wherePatternSpecified) { wherePattern = substringAfterToken(afterInsert, "WHERE"); if (StringUtils.isBlank(wherePattern) || !wherePattern.trim().startsWith("{")) { throw new ScriptParseException("Could not detect WHERE pattern!"); } } // Build the resulting CONSTRUCT query. String result = substringBeforeToken(script, "MODIFY"); result += "CONSTRUCT"; result += ensureWhitespaceStartEnd(constructTemplate); if (!StringUtils.isBlank(datasetClause)) { result += "FROM" + ensureWhitespaceStart(datasetClause); } result = ensureWhitespaceEnd(result); if (!StringUtils.isBlank(wherePattern)) { result += "WHERE" + ensureWhitespaceStart(wherePattern); } else { result += "WHERE {?s ?p ?o}"; } result = result.trim(); result += " LIMIT " + TEST_RESULTS_LIMIT; return result; } /** * * @param script * @return * @throws ScriptParseException */ private static String deriveConstructFromInsert(String script) throws ScriptParseException { String constructTemplate = null; String datasetClause = null; String wherePattern = null; String graphAndTemplate = null; boolean datasetSpecified = containsToken(script, "FROM"); boolean wherePatternSpecified = containsToken(script, "WHERE"); // Extract the graph-and-template section, and the dataset section if present. if (datasetSpecified) { graphAndTemplate = substringBetweenTokens(script, "INSERT", "FROM"); if (wherePatternSpecified) { datasetClause = substringBetweenTokens(script, "FROM", "WHERE"); } else { datasetClause = substringAfterToken(script, "FROM"); } } else if (wherePatternSpecified) { graphAndTemplate = substringBetweenTokens(script, "INSERT", "WHERE"); } else { graphAndTemplate = substringAfterToken(script, "INSERT"); } // Extract construct template, make sure it's not blank and starts-ends with curly braces. int i = graphAndTemplate.indexOf("{"); if (i != -1) { constructTemplate = graphAndTemplate.substring(i); } if (constructTemplate == null || !startsEndsWith(constructTemplate.trim(), "{", "}")) { throw new ScriptParseException("Could not detect CONSTRUCT template!"); } // Extract WHERE pattern if present if (wherePatternSpecified) { wherePattern = substringAfterToken(script, "WHERE"); if (StringUtils.isBlank(wherePattern) || !wherePattern.trim().startsWith("{")) { throw new ScriptParseException("Could not detect WHERE pattern!"); } } String result = substringBeforeToken(script, "INSERT"); result += "CONSTRUCT"; result += ensureWhitespaceStartEnd(constructTemplate); if (!StringUtils.isBlank(datasetClause)) { result += "FROM" + ensureWhitespaceStart(datasetClause); } result = ensureWhitespaceEnd(result); if (!StringUtils.isBlank(wherePattern)) { result += "WHERE" + ensureWhitespaceStart(wherePattern); } else { result += "WHERE {?s ?p ?o}"; } result = result.trim(); result += " LIMIT " + TEST_RESULTS_LIMIT; return result; } /** * * @param script * @return * @throws ScriptParseException */ private static String deriveConstructFromDelete(String script) throws ScriptParseException { String constructTemplate = null; String datasetClause = null; String wherePattern = null; boolean wherePatternSpecified = containsToken(script, "WHERE"); // Extract the CONSTRUCT template, and the dataset section if present. String afterDelete = substringAfterToken(script, "DELETE"); int i = afterDelete.indexOf("{"); if (i != -1) { String afterGraph = afterDelete.substring(i); if (containsToken(afterGraph, "FROM")) { constructTemplate = substringBeforeToken(afterGraph, "FROM"); if (wherePatternSpecified) { datasetClause = substringBetweenTokens(afterGraph, "FROM", "WHERE"); } else { datasetClause = substringAfterToken(afterGraph, "FROM"); } } else if (containsToken(afterGraph, "WHERE")) { constructTemplate = substringBeforeToken(afterGraph, "WHERE"); } else { constructTemplate = afterGraph; } } // Ensure CONSTRUCT template is not blank and starts-ends with curly braces if (constructTemplate == null || !startsEndsWith(constructTemplate.trim(), "{", "}")) { throw new ScriptParseException("Could not detect CONSTRUCT template!"); } // Extract WHERE pattern if present if (wherePatternSpecified) { wherePattern = substringAfterToken(script, "WHERE"); if (StringUtils.isBlank(wherePattern) || !wherePattern.trim().startsWith("{")) { throw new ScriptParseException("Could not detect WHERE pattern!"); } } // Build the resulting CONSTRUCT query. String result = substringBeforeToken(script, "DELETE"); result += "CONSTRUCT"; result += ensureWhitespaceStartEnd(constructTemplate); if (!StringUtils.isBlank(datasetClause)) { result += "FROM" + ensureWhitespaceStart(datasetClause); } result = ensureWhitespaceEnd(result); if (!StringUtils.isBlank(wherePattern)) { result += "WHERE" + ensureWhitespaceStart(wherePattern); } else { result += "WHERE {?s ?p ?o}"; } result = result.trim(); result += " LIMIT " + TEST_RESULTS_LIMIT; return result; } /** * * @param str * @param token * @return */ public static boolean containsToken(String str, String token) { if (str == null || str.trim().length() == 0 || token == null || token.trim().length() == 0) { return false; } StringTokenizer st = new StringTokenizer(str, " \t\n\r\f", true); ArrayList<String> upperCaseTokens = new ArrayList<String>(); while (st.hasMoreTokens()) { String nextToken = st.nextToken(); upperCaseTokens.add(nextToken.toUpperCase()); } return upperCaseTokens.contains(token.toUpperCase()); } /** * * @param str * @param token * @return */ private static String substringBeforeToken(String str, String token) { if (str == null || str.trim().length() == 0 || token == null || token.trim().length() == 0) { return str; } StringTokenizer st = new StringTokenizer(str, " \t\n\r\f", true); ArrayList<String> originalTokens = new ArrayList<String>(); ArrayList<String> upperCaseTokens = new ArrayList<String>(); while (st.hasMoreTokens()) { String nextToken = st.nextToken(); originalTokens.add(nextToken); upperCaseTokens.add(nextToken.toUpperCase()); } int tokenIndex = upperCaseTokens.indexOf(token.toUpperCase()); if (tokenIndex >= 0) { return tokensToString(originalTokens.subList(0, tokenIndex)); } else { return str; } } /** * * @param str * @param token * @return */ private static String substringAfterToken(String str, String token) { if (str == null || str.trim().length() == 0 || token == null || token.trim().length() == 0) { return str; } StringTokenizer st = new StringTokenizer(str, " \t\n\r\f", true); ArrayList<String> originalTokens = new ArrayList<String>(); ArrayList<String> upperCaseTokens = new ArrayList<String>(); while (st.hasMoreTokens()) { String nextToken = st.nextToken(); originalTokens.add(nextToken); upperCaseTokens.add(nextToken.toUpperCase()); } int tokenIndex = upperCaseTokens.indexOf(token.toUpperCase()); if (tokenIndex >= 0) { String afterToken = ""; int tokensSize = originalTokens.size(); if (tokenIndex < tokensSize - 1) { afterToken = tokensToString(originalTokens.subList(tokenIndex + 1, tokensSize)); } return afterToken; } else { return str; } } /** * Returns the substring that is between the given tokens (tokens themselves excluded). If neither tokens are present in the * string, the string itself is returned. If token1 is present in the string, but token2 is not, then the substring after token1 * is returned. Similarly, if token2 is present in the string, but token1 is not, then the substring before token1 is returned. * If neither tokens are present in the string, the string is returned as it is. * * If the given string is blank (i.e. null or empty after trimmed), the given string is returned as it is. If token1 is not * blank, but token2 is, the method returns substring after token1. If token2 is not blank, but token1 is, the method returns * substring before token1. If both tokens are blank, the string is returned as it is. * * @param str The given string. * @param token1 token1 * @param token2 token2 * @return See method description above. */ private static String substringBetweenTokens(String str, String token1, String token2) { if (StringUtils.isBlank(str) || (StringUtils.isBlank(token1) && StringUtils.isBlank(token2))) { return str; } if (!StringUtils.isBlank(token1) && StringUtils.isBlank(token2)) { return substringAfterToken(str, token1); } else if (StringUtils.isBlank(token1) && !StringUtils.isBlank(token2)) { return substringBeforeToken(str, token2); } else { String afterToken1 = substringAfterToken(str, token1); return substringBeforeToken(afterToken1, token2); } } /** * * @param str * @param tokenToReplace * @param replacement * @return */ private static String replaceToken(String str, String tokenToReplace, String replacement) { if (str == null || str.trim().length() == 0 || tokenToReplace == null || tokenToReplace.trim().length() == 0) { return str; } StringTokenizer st = new StringTokenizer(str, " \t\n\r\f", true); ArrayList<String> originalTokens = new ArrayList<String>(); ArrayList<String> upperCaseTokens = new ArrayList<String>(); while (st.hasMoreTokens()) { String nextToken = st.nextToken(); originalTokens.add(nextToken); upperCaseTokens.add(nextToken.toUpperCase()); } StringBuilder buf = new StringBuilder(); for (String token : originalTokens) { if (token.equalsIgnoreCase(tokenToReplace)) { buf.append(replacement); } else { buf.append(token); } } return buf.toString(); } /** * * @param tokens * @return */ private static String tokensToString(Collection<String> tokens) { StringBuilder result = new StringBuilder(); if (tokens != null) { for (String token : tokens) { result.append(token); } } return result.toString(); } /** * * @param str * @param start * @param end * @return */ private static boolean startsEndsWith(String str, String start, String end) { if (str == null) { return false; } return str.startsWith(start) && str.endsWith(end); } /** * * @param str * @return */ private static String ensureWhitespaceStart(String str) { if (str == null) { return null; } else if (str.length() == 0 || !Character.isWhitespace(str.charAt(0))) { return " " + str; } else { return str; } } /** * * @param str * @return */ private static String ensureWhitespaceEnd(String str) { if (str == null) { return null; } else if (str.length() == 0 || !Character.isWhitespace(str.charAt(str.length() - 1))) { return str + " "; } else { return str; } } /** * * @param str * @return */ private static String ensureWhitespaceStartEnd(String str) { if (str == null) { return null; } else if (str.length() == 0) { return " "; } else { String result = str; if (!Character.isWhitespace(result.charAt(0))) { result = " " + result; } if (!Character.isWhitespace(result.charAt(result.length() - 1))) { result = result + " "; } return result; } } }