Application: gvSIG desktop

package org.gvsig.fmap.dal.impl.expressionevaluator;

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.SymbolTable;

import org.gvsig.expressionevaluator.Compiler;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorManager;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.fmap.dal.expressionevaluator.FeatureSymbolTable;

import org.gvsig.fmap.dal.feature.Feature;

import org.gvsig.tools.evaluator.AbstractEvaluator;

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.evaluator.EvaluatorData;

import org.gvsig.tools.evaluator.EvaluatorException;

import org.gvsig.tools.evaluator.EvaluatorFieldsInfo;

import org.gvsig.tools.evaluator.EvaluatorWithDescriptions;

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 EvaluatorWithDescriptions, 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 FeatureSymbolTable featureSymbolTable;

    private Compiler compiler;

    private Interpreter interpreter;

    private Code code;

    private Expression expression;

    private Description[] availableOperators;

    private Description[] availableFunctions;

    public DefaultExpressionEvaluator(String source) {

        this.featureSymbolTable = new DefaultFeatureSymbolTable();

        this.expression = ExpressionEvaluatorLocator.getManager().createExpression();

        this.expression.setPhrase(source);

    }

    public DefaultExpressionEvaluator(Expression expression) {

        this.expression = expression;

        this.featureSymbolTable = new DefaultFeatureSymbolTable(

                expression.getUserScript(), 

                expression.getScripts()

        );

    }

    @Override

    public Object evaluate(EvaluatorData data) throws EvaluatorException {

        if (this.code == null) {

            this.compile();

        }

        Interpreter theInterpreter = this.getInterpreter();

        theInterpreter.getSymbolTable().addSymbolTable(this.featureSymbolTable);

        this.featureSymbolTable.setFeature((Feature) 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.compile().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 : getSymbolTable()) {

                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 : getSymbolTable()) {

                if (!function.isOperator()) {

                    l.add(new DescriptionAdapter(function));

                }

            }

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

        }

        return availableFunctions;

    }

    private SymbolTable getSymbolTable() {

        return this.getInterpreter().getSymbolTable();

    }

    private Interpreter getInterpreter() {

        if (this.interpreter == null) {

            ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

            this.interpreter = manager.createInterpreter();

            this.interpreter.setAccuracy(ExpressionEvaluatorLocator.getManager().getAccuracy());

        }

        return interpreter;

    }

    private Compiler getCompiler() {

        if (this.compiler == null) {

            ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

            this.compiler = manager.createCompiler();

        }

        return compiler;

    }

    private Code compile() {

        if (this.code == null) {

            ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

            this.code = this.getCompiler().compileExpression(expression.getPhrase());

        }

        return code;

    }

    @Override

    public Evaluator clone() throws CloneNotSupportedException {

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

        other.code = this.code;

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

        other.availableFunctions = null;

        other.availableOperators = null;

        if (this.featureSymbolTable != null) {

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

        }

        if (this.compiler != null) {

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

        }

        if (this.interpreter != null) {

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

        }

        return other;

    }

}