001: /* ====================================================================
002: * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
003: *
004: * Copyright (c) 1995-2002 Jcorporate Ltd. 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 copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * 2. Redistributions in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * 3. The end-user documentation included with the redistribution,
019: * if any, must include the following acknowledgment:
020: * "This product includes software developed by Jcorporate Ltd.
021: * (http://www.jcorporate.com/)."
022: * Alternately, this acknowledgment may appear in the software itself,
023: * if and wherever such third-party acknowledgments normally appear.
024: *
025: * 4. "Jcorporate" and product names such as "Expresso" must
026: * not be used to endorse or promote products derived from this
027: * software without prior written permission. For written permission,
028: * please contact info@jcorporate.com.
029: *
030: * 5. Products derived from this software may not be called "Expresso",
031: * or other Jcorporate product names; nor may "Expresso" or other
032: * Jcorporate product names appear in their name, without prior
033: * written permission of Jcorporate Ltd.
034: *
035: * 6. No product derived from this software may compete in the same
036: * market space, i.e. framework, without prior written permission
037: * of Jcorporate Ltd. For written permission, please contact
038: * partners@jcorporate.com.
039: *
040: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
041: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
042: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
043: * DISCLAIMED. IN NO EVENT SHALL JCORPORATE LTD OR ITS CONTRIBUTORS
044: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
045: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
046: * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
047: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
048: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
049: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
050: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
051: * SUCH DAMAGE.
052: * ====================================================================
053: *
054: * This software consists of voluntary contributions made by many
055: * individuals on behalf of the Jcorporate Ltd. Contributions back
056: * to the project(s) are encouraged when you make modifications.
057: * Please send them to support@jcorporate.com. For more information
058: * on Jcorporate Ltd. and its products, please see
059: * <http://www.jcorporate.com/>.
060: *
061: * Portions of this software are based upon other open source
062: * products and are subject to their respective licenses.
063: */
064:
065: package com.jcorporate.expresso.core.dataobjects;
066:
067: import java.io.InputStream;
068: import java.math.BigDecimal;
069: import java.util.Date;
070: import java.util.Map;
071:
072: /**
073: * This class represents a single field of data that is stored within the
074: * data object. It will provide basic manipulations such as it's original
075: * value, and attribute holdings.
076: *
077: * @author Michael Rimov
078: * @since Expresso 5.0.1
079: */
080:
081: public interface DataField {
082:
083: /**
084: * Retrieves the wrapped object for the Data Field
085: *
086: * @return java.lang.Object or null
087: */
088: public Object getValue();
089:
090: /**
091: * Retrieves the wrapped object as a String
092: *
093: * @return java.lang.String
094: */
095: public String asString();
096:
097: /**
098: * Retrieve the boolean object value.
099: *
100: * @return java.lang.Boolean
101: */
102: public Boolean asBoolean();
103:
104: /**
105: * Retrieves the wrapped object as an <code>Integer</code> or zero if it's an invalid format.
106: *
107: * @return a java.lang.Integer object, or null if the object is null.
108: */
109: public Integer asInteger();
110:
111: /**
112: * Retrieve the wrapped object as a <code>Date</code> object or possibly null if we
113: * can't convert it or the object is null.
114: *
115: * @return a properly instantiated <code>Date</code> Object if we're able to convert it.
116: */
117: public Date asDate();
118:
119: /**
120: * Retrieve the wrapped object as a <code>BigDecimal</code> object or zero if we're unable
121: * to convert it.
122: *
123: * @return a properly instantiated <code>BigDecimal</code> Object if we're able to convert it.
124: */
125: public BigDecimal asBigDecimal();
126:
127: /**
128: * Retrieve the wrapped object as a <code>Double</code> object or zero if we
129: * can't convert i
130: *
131: * @return a properly instantiated <code>Double</code> Object if we're able to convert it.
132: */
133: public Double asDouble();
134:
135: /**
136: * @return the original object or null
137: * @deprecated 8/04 v.5.5 do not expose this cache
138: * Retrieve the last original value if the data has changed. Will return
139: * null if isChanged() is false
140: */
141: public Object getOriginalValue();
142:
143: /**
144: * Allows for retrieval of BLOB database types.
145: *
146: * @return java.io.InputStream
147: */
148: public InputStream asStream();
149:
150: /**
151: * Used for change logging.
152: *
153: * @return true if the field has changed since the last reset
154: */
155: public boolean isChanged();
156:
157: /**
158: * Used for change logging.
159: *
160: * @return true if the field has been set since the last reset
161: */
162: public boolean isValueSet();
163:
164: /**
165: * Make sure the value of the field is valid.
166: *
167: * @throws DataException if the field value is not valid
168: */
169: public void checkValue() throws DataException;
170:
171: /**
172: * Resets the changed flag and sets the original value field to null
173: */
174: public void resetChanged();
175:
176: /**
177: * Sets the wrapped object for the data field
178: *
179: * @param newValue a new Object to set the value to
180: */
181: public void setValue(Object newValue);
182:
183: /**
184: * Returns true if the object is null.
185: *
186: * @return true if the object is null
187: */
188: public boolean isNull();
189:
190: /**
191: * Sets an attribute for this particular instance of the Data field
192: *
193: * @param attributeName the name of the attribute to set
194: * @param value the value to set it to
195: */
196: public void setAttribute(String attributeName, Object value);
197:
198: /**
199: * Retrieves any user defined attributes for this field.
200: *
201: * @param attributeName the name of the attribute to retrieve
202: * @return an object or null if the attribute doesn't exist
203: */
204: public Object getAttribute(String attributeName);
205:
206: /**
207: * Returns a Read Only <code>Map</code> of all attributes in name-value pairs. If there are no
208: * attributes then getAllAttributes will return a null map.
209: *
210: * @return java.util.map
211: */
212: public Map getAllAttributes();
213:
214: /**
215: * Returns a handle to the DataObject that is the container for this
216: * Data Field
217: *
218: * @return DataObject the containing data object.
219: */
220: public DataObject getOwner();
221:
222: /**
223: * Sets the owner of a given DataObject
224: *
225: * @param newOwner The new parent object.
226: */
227: public void setOwner(DataObject newOwner);
228:
229: /**
230: * Returns a handle to the Field MetaData object.
231: *
232: * @return DataFieldMetaData
233: */
234: public DataFieldMetaData getFieldMetaData();
235:
236: /**
237: * Sets the metadata object for this field.
238: *
239: * @param newMetadata the new Field Meta data object... for example <code>DBField</code>
240: */
241: public void setFieldMetaData(DataFieldMetaData newMetadata);
242:
243: /**
244: * call after add() or update(). The currentValue of data fields should be considered the baseline, the 'original value' for purposes of determining 'isChanged'
245: */
246: public void cacheIsChangedComparison();
247: }
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