Java tutorial
/* * 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 ro.nextreports.engine.querybuilder.sql.dialect; import java.math.BigDecimal; import java.math.BigInteger; import java.sql.Types; import java.sql.Timestamp; import java.sql.Time; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * Represents a dialect of SQL implemented by a particular RDBMS. * <br> * Subclasses should provide a public default constructor that <tt>register()</tt> * a set of type mappings and.<br> * <br> * * @author Decebal Suiu */ public abstract class AbstractDialect implements Dialect { protected static final Log LOG = LogFactory.getLog(AbstractDialect.class); private List<ColumnTypeMatcher> columnTypeMatchers = new ArrayList<ColumnTypeMatcher>(); // private Map<String, Integer> jdbcTypes = new TreeMap<String, Integer>(String.CASE_INSENSITIVE_ORDER); private Map<String, Integer> jdbcTypes = new HashMap<String, Integer>(); private Map<Integer, String> javaTypes = new HashMap<Integer, String>(); // uppercase keywords : an array of known keywords that are allowed to be used as // table or column names protected String[] keywords = new String[0]; public AbstractDialect() { LOG.info("Using dialect: " + this); setKeywords(); registerDefaultJavaTypes(); } /** * Get <tt>java.sql.Types</tt> typecode of the column database associated * with the given sql type, precision and scale. * * @param type sql type * @param precision the precision of the column * @param scale the scale of the column * * @return the column typecode * @throws DialectException */ public final int getJdbcType(String type, int precision, int scale) throws DialectException { // TODO ?! // SQLite returns "null" for type if we use rsmd.getColumnTypeName if ((type == null) || "null".equals(type)) { return Types.OTHER; } List<ColumnTypeMatcher> typeMatchers = matchType(type, columnTypeMatchers); if (typeMatchers.size() == 0) { throw new DialectException("Cannot match the type '" + type + "' to a jdbc type"); } if (typeMatchers.size() == 1) { return jdbcTypes.get(typeMatchers.get(0).getColumnType()); } List<ColumnTypeMatcher> precisionMatchers = matchPrecision(precision, typeMatchers); if (precisionMatchers.size() == 0) { throw new DialectException("Cannot match the precision '" + precision + "' to a jdbc type"); } if (precisionMatchers.size() == 1) { return jdbcTypes.get(precisionMatchers.get(0).getColumnType()); } List<ColumnTypeMatcher> scaleMatchers = matchScale(scale, typeMatchers); if (scaleMatchers.size() == 0) { throw new DialectException("Cannot match the scale '" + scale + "' to a jdbc type"); } if (scaleMatchers.size() == 1) { return jdbcTypes.get(scaleMatchers.get(0).getColumnType()); } return jdbcTypes.get(chooseOne(scaleMatchers).getColumnType()); } public final String getJavaType(String type, int precision, int scale) throws DialectException { return javaTypes.get(getJdbcType(type, precision, scale)); } /** * Subclasses register a typename for the given type code. * * @param columnType the database column type * @param jdbcType <tt>java.sql.Types</tt> typecode */ protected void registerColumnType(String columnType, int jdbcType) { columnTypeMatchers.add(new ColumnTypeMatcher(columnType)); jdbcTypes.put(columnType, jdbcType); } public boolean hasProcedureWithCursor() { return false; } public boolean schemaBeforeCatalog() { return true; } protected void registerDefaultJavaTypes() { registerJavaType(Types.BIT, Boolean.class.getName()); registerJavaType(Types.TINYINT, Byte.class.getName()); registerJavaType(Types.SMALLINT, Short.class.getName()); // registerJavaType(Types.CHAR, Character.class.getName()); registerJavaType(Types.CHAR, String.class.getName()); registerJavaType(Types.VARCHAR, String.class.getName()); registerJavaType(Types.DATE, Date.class.getName()); registerJavaType(Types.TIME, Time.class.getName()); registerJavaType(Types.TIMESTAMP, Timestamp.class.getName()); registerJavaType(Types.DOUBLE, Double.class.getName()); registerJavaType(Types.FLOAT, Float.class.getName()); registerJavaType(Types.INTEGER, Integer.class.getName()); registerJavaType(Types.BIGINT, BigInteger.class.getName()); // registerJavaType(Types.BIGINT, Long.class.getName()); registerJavaType(Types.NUMERIC, BigDecimal.class.getName()); registerJavaType(Types.DECIMAL, BigDecimal.class.getName()); registerJavaType(Types.BINARY, byte[].class.getName()); registerJavaType(Types.VARBINARY, byte[].class.getName()); registerJavaType(Types.BLOB, String.class.getName()); registerJavaType(Types.CLOB, String.class.getName()); registerJavaType(Types.REAL, String.class.getName()); registerJavaType(Types.OTHER, Object.class.getName()); } protected void registerJavaType(int jdbcType, String javaType) { javaTypes.put(jdbcType, javaType); } protected List<ColumnTypeMatcher> matchType(String type, List<ColumnTypeMatcher> columnTypeMatchers) { List<ColumnTypeMatcher> typeMatchers = new ArrayList<ColumnTypeMatcher>(); for (ColumnTypeMatcher matcher : columnTypeMatchers) { if (matcher.matchType(type)) { typeMatchers.add(matcher); } } return typeMatchers; } protected List<ColumnTypeMatcher> matchPrecision(int precision, List<ColumnTypeMatcher> columnTypeMatchers) { List<ColumnTypeMatcher> precisionMatchers = new ArrayList<ColumnTypeMatcher>(); for (ColumnTypeMatcher matcher : columnTypeMatchers) { if (matcher.matchPrecision(precision)) { precisionMatchers.add(matcher); } } return precisionMatchers; } protected List<ColumnTypeMatcher> matchScale(int scale, List<ColumnTypeMatcher> columnTypeMatchers) { List<ColumnTypeMatcher> scaleMatchers = new ArrayList<ColumnTypeMatcher>(); for (ColumnTypeMatcher matcher : columnTypeMatchers) { if (matcher.matchScale(scale)) { scaleMatchers.add(matcher); } } return scaleMatchers; } protected ColumnTypeMatcher chooseOne(List<ColumnTypeMatcher> columnTypeMatchers) { return columnTypeMatchers.get(0); } public boolean isKeyWord(String word) { if (word == null) { return false; } String wordUpper = word.toUpperCase(); for (String keyword : keywords) { if (keyword.equals(wordUpper)) { return true; } } return false; } protected void setKeywords() { } public String getEscapedKeyWord(String keyword) { return keyword; } public String getCurrentTimestamp() throws DialectException { return getCurrentDate(); } public String getCurrentTime() throws DialectException { return getCurrentDate(); } public boolean needsHoldCursorsForPreparedStatement() { return false; } }