Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||
IPrimaryKeyConverter |
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| 1.0;1 |
1 | // Copyright 2004, 2005 The Apache Software Foundation |
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2 | // |
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3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
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4 | // you may not use this file except in compliance with the License. |
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5 | // You may obtain a copy of the License at |
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6 | // |
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7 | // http://www.apache.org/licenses/LICENSE-2.0 |
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8 | // |
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9 | // Unless required by applicable law or agreed to in writing, software |
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10 | // distributed under the License is distributed on an "AS IS" BASIS, |
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11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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12 | // See the License for the specific language governing permissions and |
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13 | // limitations under the License. |
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14 | ||
15 | package org.apache.tapestry.components; |
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16 | ||
17 | /** |
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18 | * An interface for converting an objects to their primary keys and back. |
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19 | * Typically used to determine how to store a given object as a hidden value |
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20 | * when rendering a form. |
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21 | * <p> |
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22 | * This interface is used by the |
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23 | * {@link org.apache.tapestry.components.ForBean For component}. When a primary |
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24 | * key converter is available, it is used during the render, and as part of the |
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25 | * rewind phase that processes the form submission. |
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26 | * <p> |
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27 | * During rendering, {@link #getPrimaryKey(Object)} is invoked for each value. |
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28 | * This method is invoked just before the For's body is rendered. The resulting |
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29 | * primary key is written into the client as a hidden form field. |
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30 | * <p> |
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31 | * Likewise, during rewind, {@link #getValue(Object)} is invoked for each key, |
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32 | * to get back the same (or equivalent) object. Again, the method is invoked |
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33 | * just before the For's body is rendered. |
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34 | * <p> |
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35 | * The {@link org.apache.tapestry.util.DefaultPrimaryKeyConverter} uses this |
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36 | * relationship between a For component and its primary key converter to track |
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37 | * what the current value being rendered or rewound is. |
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38 | * |
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39 | * @author mb |
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40 | * @since 4.0 |
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41 | */ |
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42 | public interface IPrimaryKeyConverter |
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43 | { |
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44 | ||
45 | /** |
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46 | * Returns the primary key of the given value. |
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47 | * |
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48 | * @param objValue |
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49 | * the value for which a primary key needs to be extracted |
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50 | * @return the primary key of the value |
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51 | */ |
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52 | Object getPrimaryKey(Object value); |
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53 | ||
54 | /** |
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55 | * Returns the value corresponding the given primary key. |
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56 | * |
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57 | * @param objPrimaryKey |
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58 | * the primary key for which a value needs to be generated |
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59 | * @return the generated value corresponding to the given primary key |
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60 | */ |
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61 | Object getValue(Object primaryKey); |
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62 | ||
63 | } |