95 lines
2.6 KiB
Java
95 lines
2.6 KiB
Java
/*******************************************************************************
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* Copyright (c) 2015 MINRES Technologies GmbH and others.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* MINRES Technologies GmbH - initial API and implementation
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*******************************************************************************/
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package com.minres.scviewer.database.sqlite.db;
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import java.lang.reflect.Field;
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/**
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* An abstract class that handles insert/select-operations into/from a database
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*
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* @author Tino for http://www.java-blog.com
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*
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* @param <T>
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*/
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public abstract class AbstractDatabaseHandler<T> {
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/**
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* The type of the objects that should be created and filled with values
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* from the database or inserted into the database
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*/
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protected Class<T> type;
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/**
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* Contains the settings to create a connection to the database like
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* host/port/database/user/password
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*/
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protected IDatabase databaseConnectionFactory;
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/** The SQL-select-query */
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protected final String query;
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/**
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* Constructor
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*
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* @param type
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* The type of the objects that should be created and filled with
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* values from the database or inserted into the database
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* @param databaseConnecter
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* Contains the settings to create a connection to the database
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* like host/port/database/user/password
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*/
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protected AbstractDatabaseHandler(Class<T> type,
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IDatabase databaseConnectionFactory, String criterion) {
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this.databaseConnectionFactory = databaseConnectionFactory;
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this.type = type;
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this.query = createQuery(criterion);
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}
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/**
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* Create the SQL-String to insert into / select from the database
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*
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* @return the SQL-String
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*/
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protected abstract String createQuery(String criterion);
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/**
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*
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* Creates a comma-separated-String with the names of the variables in this
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* class
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*
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* @param usePlaceHolders
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* true, if PreparedStatement-placeholders ('?') should be used
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* instead of the names of the variables
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* @return
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*/
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protected String getColumns(boolean usePlaceHolders) {
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StringBuilder sb = new StringBuilder();
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boolean first = true;
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/* Iterate the column-names */
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for (Field f : type.getDeclaredFields()) {
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if (first)
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first = false;
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else
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sb.append(", ");
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if (usePlaceHolders)
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sb.append("?");
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else
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sb.append(f.getName());
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}
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return sb.toString();
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}
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}
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