svn-gvsig-desktop / trunk / libraries / libGDBMS / src / com / hardcode / gdbms / engine / instruction / AbstractExpression.java @ 1956
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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.Value; |
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/**
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* Adaptador
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*
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* @author Fernando Gonz?lez Cort?s
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*/
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public abstract class AbstractExpression extends Adapter implements Expression { |
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protected boolean literal; |
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private Value value;
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/**
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* @see com.hardcode.gdbms.engine.instruction.Expression#evaluateExpression(long)
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*/
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public Value evaluateExpression(long row) |
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throws SemanticException, DriverException {
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if (!isLiteral()) {
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return evaluate(row);
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} else {
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if (value == null) { |
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return (value = evaluate(row));
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} else {
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return value;
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} |
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} |
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} |
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} |