root / trunk / libraries / libGDBMS / src / main / java / com / hardcode / gdbms / engine / instruction / NotExprAdapter.java @ 10627
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package com.hardcode.gdbms.engine.instruction; |
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import com.hardcode.gdbms.engine.data.driver.DriverException; |
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import com.hardcode.gdbms.engine.values.BooleanValue; |
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import com.hardcode.gdbms.engine.values.Value; |
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import com.hardcode.gdbms.parser.Node; |
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/**
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* Adapter de las Expresiones Not del arbol sint?ctico
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*
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* @author Fernando Gonz?lez Cort?s
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*/
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public class NotExprAdapter extends AbstractExpression implements Expression { |
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private boolean not = false; |
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/**
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* Evalua expresi?n invocando el m?todo adecuado en funci?n del tipo de
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* expresion (suma, producto, ...) de los objetos Value de la expresion,
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* de las subexpresiones y de los objetos Field
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*
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* @param row Fila en la que se eval?a la expresi?n, en este caso no es
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* necesario, pero las subexpresiones sobre las que se opera pueden
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* ser campos de una tabla, en cuyo caso si es necesario
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*
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* @return Objeto Value resultado de la operaci?n propia de la expresi?n
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* representada por el nodo sobre el cual ?ste objeto es adaptador
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*
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* @throws SemanticException Si se produce un error sem?ntico
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* @throws DriverException Si se produce un error de I/O
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* @throws IncompatibleTypesException Si la expresi?n es una negaci?n y la
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* expresi?n que se niega no es booleana
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*/
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public Value evaluate(long row) throws EvaluationException { |
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Value ret = null;
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Expression c = (Expression) getChilds()[0]; |
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try {
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Value value = c.evaluateExpression(row); |
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if (not) {
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((BooleanValue) value).setValue(!((BooleanValue) value).getValue()); |
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} |
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return value;
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} catch (ClassCastException e) { |
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throw new EvaluationException(); |
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} |
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} |
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/**
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* @see com.hardcode.gdbms.engine.instruction.Expression#getFieldName()
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*/
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public String getFieldName() { |
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return null; |
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} |
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/**
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* @see com.hardcode.gdbms.engine.instruction.Expression#isLiteral()
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*/
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public boolean isLiteral() { |
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return ((Expression) getChilds()[0]).isLiteral(); |
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} |
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/**
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* @see com.hardcode.gdbms.engine.instruction.Expression#simplify()
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*/
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public void simplify() { |
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if (!not) {
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getParent().replaceChild(this, getChilds()[0]); |
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} |
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} |
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/**
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* @see com.hardcode.gdbms.engine.instruction.Adapter#setEntity(com.hardcode.gdbms.parser.Node)
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*/
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public void setEntity(Node o) { |
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super.setEntity(o);
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String text = Utilities.getText(getEntity()).trim(); |
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if (text.startsWith("not")) { |
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not = true;
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} |
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} |
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} |