001: /*
002: * $Id: SequenceEvaluator.java,v 1.12 2005/12/22 09:02:30 ahimanikya Exp $
003: * =======================================================================
004: * Copyright (c) 2002-2006 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:
041: package org.axiondb;
042:
043: /**
044: * @version $Revision: 1.12 $ $Date: 2005/12/22 09:02:30 $
045: * @author Rodney Waldhoff
046: * @author Ahimanikya Satapathy
047: */
048: public class SequenceEvaluator implements Selectable {
049: public static final String CURRVAL = "CURRVAL";
050: public static final String NEXTVAL = "NEXTVAL";
051:
052: public SequenceEvaluator(Sequence seq, String method)
053: throws AxionException {
054: _seq = seq;
055: _method = method;
056: if (NEXTVAL.equalsIgnoreCase(method)) {
057: _nextval = true;
058: } else if (CURRVAL.equalsIgnoreCase(method)) {
059: _nextval = false;
060: } else {
061: throw new AxionException("Pseudocolumn " + method
062: + " not recognized.");
063: }
064: }
065:
066: public Object evaluate(RowDecorator row) throws AxionException {
067: if (_nextval) {
068: Object val = _seq.evaluate();
069: _ctx.put(_seq, val);
070: return val;
071: }
072:
073: if (_ctx.containsKey(_seq)) {
074: return _ctx.get(_seq);
075: }
076:
077: throw new AxionException("Sequence " + getName()
078: + " not yet evaluated in this context.");
079: }
080:
081: public String getAlias() {
082: if (_alias != null) {
083: return _alias;
084: }
085: return _seq.getName();
086: }
087:
088: public void setAlias(String alias) {
089: _alias = alias;
090: }
091:
092: public DataType getDataType() {
093: return _seq.getDataType();
094: }
095:
096: public String getLabel() {
097: if (_alias != null) {
098: return _alias;
099: }
100: return _seq.getName() + "_" + _method;
101: }
102:
103: public String getName() {
104: return _seq.getName();
105: }
106:
107: public void setVariableContext(VariableContext ctx) {
108: _ctx = ctx;
109: }
110:
111: private String _method;
112: private String _alias;
113: private VariableContext _ctx;
114: private boolean _nextval;
115: private Sequence _seq;
116: }
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