/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2006 - 2013 Pentaho Corporation and Contributors. All rights reserved.
*/
package org.pentaho.reporting.libraries.formula.lvalues;
import org.pentaho.reporting.libraries.formula.EvaluationException;
import org.pentaho.reporting.libraries.formula.FormulaContext;
import org.pentaho.reporting.libraries.formula.operators.InfixOperator;
import java.util.ArrayList;
/**
* An term is a list of LValues connected by operators. For the sake of efficiency, this is not stored as tree. We store
* the term as a list in the following format: (headValue)(OP value)* ...
*
* @author Thomas Morgner
*/
public class Term extends AbstractLValue {
private static final LValue[] EMPTY_L_VALUE = new LValue[ 0 ];
private static final InfixOperator[] EMPTY_OPERATOR = new InfixOperator[ 0 ];
private static final long serialVersionUID = -1854082494425470979L;
private LValue optimizedHeadValue;
private LValue headValue;
private ArrayList operators;
private ArrayList operands;
private InfixOperator[] operatorArray;
private LValue[] operandsArray;
private boolean initialized;
public Term( final LValue headValue ) {
if ( headValue == null ) {
throw new NullPointerException();
}
this.headValue = headValue;
}
public TypeValuePair evaluate() throws EvaluationException {
TypeValuePair result = optimizedHeadValue.evaluate();
for ( int i = 0; i < operandsArray.length; i++ ) {
final LValue value = operandsArray[ i ];
final InfixOperator op = operatorArray[ i ];
result = op.evaluate( getContext(), result, value.evaluate() );
}
return result;
}
public void add( final InfixOperator operator, final LValue operand ) {
if ( operator == null ) {
throw new NullPointerException();
}
if ( operand == null ) {
throw new NullPointerException();
}
if ( operands == null || operators == null ) {
this.operands = new ArrayList();
this.operators = new ArrayList();
}
operands.add( operand );
operators.add( operator );
initialized = false;
}
public void initialize( final FormulaContext context ) throws EvaluationException {
super.initialize( context );
if ( operands == null || operators == null ) {
this.optimizedHeadValue = headValue;
this.optimizedHeadValue.initialize( context );
this.operandsArray = EMPTY_L_VALUE;
this.operatorArray = EMPTY_OPERATOR;
return;
}
if ( initialized ) {
optimizedHeadValue.initialize( context );
for ( int i = 0; i < operandsArray.length; i++ ) {
final LValue lValue = operandsArray[ i ];
lValue.initialize( context );
}
return;
}
optimize();
this.optimizedHeadValue.initialize( context );
for ( int i = 0; i < operandsArray.length; i++ ) {
final LValue value = operandsArray[ i ];
value.initialize( context );
}
initialized = true;
}
private void optimize() {
if ( operands == null || operators == null ) {
this.optimizedHeadValue = headValue;
this.operandsArray = EMPTY_L_VALUE;
this.operatorArray = EMPTY_OPERATOR;
return;
}
final ArrayList operators = (ArrayList) this.operators.clone();
final ArrayList operands = (ArrayList) this.operands.clone();
this.optimizedHeadValue = headValue;
while ( true ) {
// now start to optimize everything.
// first, search the operator with the highest priority..
final InfixOperator op = (InfixOperator) operators.get( 0 );
int level = op.getLevel();
boolean moreThanOne = false;
for ( int i = 1; i < operators.size(); i++ ) {
final InfixOperator operator = (InfixOperator) operators.get( i );
final int opLevel = operator.getLevel();
if ( opLevel != level ) {
moreThanOne = true;
level = Math.min( opLevel, level );
}
}
if ( moreThanOne == false ) {
// No need to optimize the operators ..
break;
}
// There are at least two op-levels in this term.
Term subTerm = null;
for ( int i = 0; i < operators.size(); i++ ) {
final InfixOperator operator = (InfixOperator) operators.get( i );
if ( operator.getLevel() != level ) {
subTerm = null;
continue;
}
if ( subTerm == null ) {
if ( i == 0 ) {
subTerm = new Term( optimizedHeadValue );
optimizedHeadValue = subTerm;
} else {
final LValue lval = (LValue) operands.get( i - 1 );
subTerm = new Term( lval );
operands.set( i - 1, subTerm );
}
}
// OK, now a term exists, and we should join it.
final LValue operand = (LValue) operands.get( i );
subTerm.add( operator, operand );
operands.remove( i );
operators.remove( i );
// Rollback the current index ..
//noinspection AssignmentToForLoopParameter
i -= 1;
}
}
this.operatorArray = (InfixOperator[])
operators.toArray( new InfixOperator[ operators.size() ] );
this.operandsArray = (LValue[])
operands.toArray( new LValue[ operands.size() ] );
}
/**
* Returns any dependent lvalues (parameters and operands, mostly).
*
* @return
*/
public LValue[] getChildValues() {
if ( operandsArray == null ) {
optimize();
}
final LValue[] values = new LValue[ operandsArray.length + 1 ];
values[ 0 ] = headValue;
System.arraycopy( operandsArray, 0, values, 1, operandsArray.length );
return values;
}
public String toString() {
return toString( false );
}
public String toString( final boolean root ) {
final StringBuilder b = new StringBuilder( 100 );
if ( !root ) {
b.append( '(' );
}
b.append( headValue );
if ( operands != null && operators != null ) {
for ( int i = 0; i < operands.size(); i++ ) {
final InfixOperator op = (InfixOperator) operators.get( i );
final LValue value = (LValue) operands.get( i );
b.append( op );
b.append( value );
}
}
if ( !root ) {
b.append( ')' );
}
return b.toString();
}
/**
* Checks whether the LValue is constant. Constant lvalues always return the same value.
*
* @return
*/
public boolean isConstant() {
if ( headValue.isConstant() == false ) {
return false;
}
for ( int i = 0; i < operands.size(); i++ ) {
final LValue value = (LValue) operands.get( i );
if ( value.isConstant() == false ) {
return false;
}
}
return true;
}
public Object clone() throws CloneNotSupportedException {
final Term o = (Term) super.clone();
if ( operands != null ) {
o.operands = (ArrayList) operands.clone();
}
if ( operators != null ) {
o.operators = (ArrayList) operators.clone();
}
o.headValue = (LValue) headValue.clone();
o.optimizedHeadValue = null;
o.operandsArray = null;
o.operatorArray = null;
o.initialized = false;
return o;
}
public LValue[] getOperands() {
return (LValue[]) operands.toArray( new LValue[ operands.size() ] );
}
public InfixOperator[] getOperators() {
return (InfixOperator[]) operators.toArray( new InfixOperator[ operators.size() ] );
}
public LValue getHeadValue() {
return headValue;
}
/**
* Allows access to the post optimized head value note that without the optimization, it's difficult to traverse
* libformula's object model.
*
* @return optimized head value
*/
public LValue getOptimizedHeadValue() {
return optimizedHeadValue;
}
//
// /**
// * Allows access to the post optimized operator array
// *
// * @return optimized operator array
// */
// public InfixOperator[] getOptimizedOperators()
// {
// return operatorArray;
// }
//
// /**
// * Allows access to the post optimized operand array
// *
// * @return optimized operand array
// */
// public LValue[] getOptimizedOperands()
// {
// return operandsArray;
// }
public ParsePosition getParsePosition() {
final ParsePosition parsePosition = super.getParsePosition();
if ( parsePosition == null ) {
final int startColumn = headValue.getParsePosition().getStartColumn();
final int startLine = headValue.getParsePosition().getStartLine();
final ParsePosition lastParsePos =
operandsArray[ operandsArray.length - 1 ].getParsePosition();
final int endColumn = lastParsePos.getEndColumn();
final int endLine = lastParsePos.getEndLine();
setParsePosition( new ParsePosition( startLine, startColumn, endLine, endColumn ) );
}
return super.getParsePosition();
}
}