root / trunk / libraries / libGDBMS / src / main / java / com / hardcode / gdbms / engine / strategies / UnionDataSource.java @ 10627
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package com.hardcode.gdbms.engine.strategies; |
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import com.hardcode.gdbms.driver.exceptions.ReadDriverException; |
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import com.hardcode.gdbms.engine.data.DataSource; |
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import com.hardcode.gdbms.engine.data.persistence.Memento; |
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import com.hardcode.gdbms.engine.data.persistence.MementoException; |
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import com.hardcode.gdbms.engine.data.persistence.OperationLayerMemento; |
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import com.hardcode.gdbms.engine.values.Value; |
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/**
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* DataSource que hace la union de dos datasources
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*
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* @author Fernando Gonz?lez Cort?s
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*/
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public class UnionDataSource extends OperationDataSource { |
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private DataSource dataSource1; |
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private DataSource dataSource2; |
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/**
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* Creates a new UnionDataSource object.
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*
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* @param ds1 Primera tabla de la union
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* @param ds2 Segunda tabla de la union
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*/
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public UnionDataSource(DataSource ds1, DataSource ds2) { |
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dataSource1 = ds1; |
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dataSource2 = ds2; |
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.DataSource#open()
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*/
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public void start() throws ReadDriverException { |
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dataSource1.start(); |
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try {
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dataSource2.start(); |
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} catch (ReadDriverException e) {
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dataSource1.stop(); |
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throw e;
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} |
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.DataSource#close()
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*/
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public void stop() throws ReadDriverException { |
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dataSource1.stop(); |
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dataSource2.stop(); |
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.FieldNameAccess#getFieldIndexByName(java.lang.String)
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*/
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public int getFieldIndexByName(String fieldName) throws ReadDriverException { |
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return dataSource1.getFieldIndexByName(fieldName);
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.driver.ReadAccess#getFieldValue(long,
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* int)
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*/
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public Value getFieldValue(long rowIndex, int fieldId) |
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throws ReadDriverException {
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long tamTabla1 = dataSource1.getRowCount();
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if (rowIndex < tamTabla1) {
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return dataSource1.getFieldValue(rowIndex, fieldId);
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} else {
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return dataSource2.getFieldValue(rowIndex - tamTabla1, fieldId);
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} |
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.driver.ReadAccess#getFieldCount()
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*/
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public int getFieldCount() throws ReadDriverException { |
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return dataSource1.getFieldCount();
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.driver.ReadAccess#getFieldName(int)
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*/
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public String getFieldName(int fieldId) throws ReadDriverException { |
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return dataSource1.getFieldName(fieldId);
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.driver.ReadAccess#getRowCount()
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*/
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public long getRowCount() throws ReadDriverException { |
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return dataSource1.getRowCount() + dataSource2.getRowCount();
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.driver.ObjectDriver#getFieldType(int)
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*/
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public int getFieldType(int i) throws ReadDriverException { |
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return dataSource1.getFieldType(i);
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} |
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/**
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* @see com.hardcode.gdbms.engine.data.DataSource#getMemento()
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*/
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public Memento getMemento() throws MementoException { |
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return new OperationLayerMemento(getName(), |
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new Memento[] { dataSource1.getMemento(), dataSource2.getMemento() }, getSQL()); |
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} |
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public int getFieldWidth(int i) throws ReadDriverException { |
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return dataSource1.getFieldWidth(i);
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} |
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} |