001: /*
002: * $Id: TrimFunction.java,v 1.5 2005/07/06 18:44:25 ahimanikya Exp $
003: * =======================================================================
004: * Copyright (c) 2004 Axion Development Team. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above
011: * copyright notice, this list of conditions and the following
012: * disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The names "Tigris", "Axion", nor the names of its contributors may
020: * not be used to endorse or promote products derived from this
021: * software without specific prior written permission.
022: *
023: * 4. Products derived from this software may not be called "Axion", nor
024: * may "Tigris" or "Axion" appear in their names without specific prior
025: * written permission.
026: *
027: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
028: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
029: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
030: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
031: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
032: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
033: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
034: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
035: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
036: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
037: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
038: * =======================================================================
039: */
040: package org.axiondb.functions;
041:
042: import org.axiondb.AxionException;
043: import org.axiondb.DataType;
044: import org.axiondb.FunctionFactory;
045: import org.axiondb.RowDecorator;
046: import org.axiondb.types.CharacterType;
047: import org.axiondb.types.IntegerType;
048: import org.axiondb.types.StringType;
049:
050: /**
051: * TRIM ( [LEADING| TRAILING| BOTH] [ trim-character ] FROM ] trim-source) function
052: *
053: * @version $Revision: 1.5 $ $Date: 2005/07/06 18:44:25 $
054: * @author Ahimanikya Satapathy
055: */
056: public class TrimFunction extends BaseFunction implements
057: ScalarFunction, FunctionFactory {
058:
059: /** Creates a new instance of Class */
060: public TrimFunction() {
061: super ("TRIM");
062: }
063:
064: public ConcreteFunction makeNewInstance() {
065: return new TrimFunction();
066: }
067:
068: /** {@link StringType} */
069: public DataType getDataType() {
070: return RETURN_TYPE;
071: }
072:
073: public Object evaluate(RowDecorator row) throws AxionException {
074: char trimChar = ' '; // default trim char
075: if (getArgumentCount() == 3) {
076: Object trimCharObj = getArgument(2).evaluate(row);
077: String trimCharStr = (String) CHAR_TYPE
078: .convert(trimCharObj);
079: if (trimCharStr != null) {
080: trimChar = trimCharStr.charAt(0);
081: }
082: }
083:
084: Object trimSourceObj = getArgument(1).evaluate(row);
085: String trimSourceStr = (String) RETURN_TYPE
086: .convert(trimSourceObj);
087:
088: Object trimTypeObj = getArgument(0).evaluate(row);
089: int type = ((Integer) INT_TYPE.convert(trimTypeObj)).intValue();
090:
091: if (type == 1 || type == 3) { // Leading or Both
092: int trimSourceLen = trimSourceStr.length();
093: int i = 0;
094: for (; i < trimSourceLen
095: && trimSourceStr.charAt(i) == trimChar; i++)
096: ;
097: trimSourceStr = ((i == 0) ? trimSourceStr : trimSourceStr
098: .substring(i));
099: }
100:
101: if (type == 2 || type == 3) { // Trailing or Both
102: int trimSourceLen = trimSourceStr.length();
103: int i, len = trimSourceLen - 1;
104: for (i = len; i > 0 && trimSourceStr.charAt(i) == trimChar; i--)
105: ;
106: trimSourceStr = (i == len) ? trimSourceStr : trimSourceStr
107: .substring(0, i + 1);
108: }
109:
110: return trimSourceStr;
111: }
112:
113: public boolean isValid() {
114: return (getArgumentCount() >= 1 && getArgumentCount() < 4);
115: }
116:
117: private static final DataType RETURN_TYPE = new StringType();
118: private static final DataType CHAR_TYPE = new CharacterType(1);
119: private static final DataType INT_TYPE = new IntegerType();
120: }
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