Application: gvSIG desktop

package org.gvsig.expressionevaluator.integration;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.LexicalAnalyzer;

import org.gvsig.expressionevaluator.SymbolTable;

import org.gvsig.expressionevaluator.Compiler;

import org.gvsig.expressionevaluator.ExpressionEvaluator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.impl.DefaultCompiler;

import org.gvsig.expressionevaluator.impl.DefaultInterpreter;

import org.gvsig.expressionevaluator.impl.SQLLexicalAnalyzer;

import org.gvsig.expressionevaluator.impl.SQLSymbolTable;

import org.gvsig.tools.evaluator.AbstractEvaluator;

import org.gvsig.tools.evaluator.EvaluatorData;

import org.gvsig.tools.evaluator.EvaluatorException;

import org.gvsig.tools.evaluator.EvaluatorFieldsInfo;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.visitor.VisitCanceledException;

import org.gvsig.tools.visitor.Visitor;

import org.gvsig.tools.lang.Cloneable;

public class DefaultExpressionEvaluator extends AbstractEvaluator implements ExpressionEvaluator, Cloneable {

    private static class DescriptionAdapter implements Description {

        Function function;

        public DescriptionAdapter(Function function) {

            this.function = function;

        }

        @Override

        public String getName() {

            return this.function.name();

        }

        @Override

        public String getDescription() {

            return this.function.description();

        }

        @Override

        public String getTemplate() {

            return this.function.template();

        }

        @Override

        public int getDataTypeCategories() {

            switch(this.function.group()) {

            case Function.GROUP_STRING:

                return Description.DATATYPE_CATEGORY_STRING;

            case Function.GROUP_BOOLEAN:

                return Description.DATATYPE_CATEGORY_BOOLEAN;

            case Function.GROUP_DATETIME:

                return Description.DATATYPE_CATEGORY_DATETIME;

            case Function.GROUP_NUMERIC:

                return Description.DATATYPE_CATEGORY_NUMBER;

            case Function.GROUP_OGC:

                return Description.DATATYPE_CATEGORY_ALL;

            default:

                return Description.DATATYPE_CATEGORY_ALL;

            }

        }

    } 

    private EvaluatorDataAdapter evaluatorData;

    private SymbolTable symbolTable;

    private LexicalAnalyzer lexer;

    private Compiler compiler;

    private Interpreter interpreter;

    private Code code;

    private String source;

    private Description[] availableOperators;

    private Description[] availableFunctions;

    private Double accuracy;

    public DefaultExpressionEvaluator() {

        super();

        this.accuracy = ExpressionEvaluatorLocator.getManager().getAccuracy();

    }

    @Override

    public Code getCode() {

        return this.code;

    }

    @Override

    public void compile() {

        if( this.symbolTable == null ) {

            this.symbolTable = SQLSymbolTable.getInstance();

        }

        if( this.lexer == null ) {

            this.lexer = new SQLLexicalAnalyzer();

        }

        if( this.compiler == null ) {

            this.compiler = new DefaultCompiler();

            this.compiler.setLexicalAnalyzer(lexer);

        }        

        if( this.interpreter == null ) {

            this.interpreter = new DefaultInterpreter();

        }

        this.evaluatorData = new EvaluatorDataAdapter(symbolTable);

        this.interpreter.setAccuracy(this.accuracy); 

        this.interpreter.setSymbolTable(this.evaluatorData);

        this.code = this.compiler.compileExpression(source);

    }

    @Override

    public Object evaluate(EvaluatorData data) throws EvaluatorException {

        if( this.code == null ) {

            this.compile();

        }

        this.evaluatorData.setData(data);

        Object v = this.interpreter.run(code);

        return v;

    }

    @Override

    public String getName() {

        return "Genereric expression";

    }

    @Override

    public EvaluatorFieldsInfo getFieldsInfo() {

        final Set<String> names = new HashSet<>();        

        try {

            this.code.accept(new Visitor() {

                @Override

                public void visit(Object code) throws VisitCanceledException, BaseException {

                    if( code instanceof Code.Identifier ) {

                        Code.Identifier identifier = (Code.Identifier) code;

                        names.add(identifier.name());

                    }

                }

            });

            EvaluatorFieldsInfo info = new EvaluatorFieldsInfo();

            for (String name : names) {

                info.addFieldValue(name);

            }

            return info;

        } catch (BaseException ex) {

            throw new RuntimeException("Can't calculate fields information.", ex);

        }

    }

    @Override

    public Description[] getAvailableOperators() {

        if( availableOperators==null ) {

            List<Description> l = new ArrayList<>();

            for( Function function : symbolTable) {

                if( function.isOperator() ) {

                    l.add(new DescriptionAdapter(function));

                }

            }

            this.availableOperators = l.toArray(new Description[l.size()]);

        }

        return availableOperators;

    }

    @Override

    public Description[] getAvailableFunctions() {

        if( availableFunctions==null ) {

            List<Description> l = new ArrayList<>();

            for( Function function : symbolTable) {

                if( !function.isOperator() ) {

                    l.add(new DescriptionAdapter(function));

                }

            }

            this.availableFunctions = l.toArray(new Description[l.size()]);

        }

        return availableFunctions;

    }

    @Override

    public SymbolTable getSymbolTable() {

        return symbolTable;

    }

    @Override

    public void setSymbolTable(SymbolTable symbolTable) {

        this.symbolTable = symbolTable;

    }

    @Override

    public LexicalAnalyzer getLexer() {

        return lexer;

    }

    @Override

    public void setLexer(LexicalAnalyzer lexer) {

        this.lexer = lexer;

    }

    @Override

    public Compiler getCompiler() {

        return compiler;

    }

    @Override

    public void setCompiler(Compiler compiler) {

        this.compiler = compiler;

    }

    @Override

    public Interpreter getInterpreter() {

        return interpreter;

    }

    @Override

    public void setInterpreter(Interpreter interpreter) {

        this.interpreter = interpreter;

    }

    @Override

    public String getSource() {

        return source;

    }

    @Override

    public void setSource(String source) {

        this.source = source;

        this.code = null;

    }

    @Override

    public Double getAccuracy() {

        return this.accuracy;

    }

    @Override

    public void setAccuracy(Double accuracy) {

        this.accuracy = accuracy;

    }

    @Override

    public ExpressionEvaluator clone() throws CloneNotSupportedException {

        DefaultExpressionEvaluator other = (DefaultExpressionEvaluator) super.clone();

        other.code = this.code;

        other.source = this.source;

        other.accuracy = this.accuracy;

        other.availableFunctions = null;

        other.availableOperators = null;

        if( this.symbolTable!=null ) {

            other.symbolTable = this.symbolTable.clone();

        }

        if( this.lexer!=null ) {

            other.lexer = this.lexer.clone();

        }

        if( this.evaluatorData!=null ) {

            // evaluatorData don't support clone.

            other.evaluatorData = new EvaluatorDataAdapter(other.symbolTable);

        }

        if( this.compiler!=null ) {

            other.compiler = this.compiler.clone();

            other.compiler.setLexicalAnalyzer(other.lexer);

        }

        if( this.interpreter!=null ) {

            other.interpreter = this.interpreter.clone();

            other.interpreter.setAccuracy(this.accuracy);

            other.interpreter.setSymbolTable(other.symbolTable);

        }

        return other;

    }

}