src/main/java/org/apache/sling/scripting/sightly/java/compiler/impl/operator/ComparisonOpGen.java

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 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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package org.apache.sling.scripting.sightly.java.compiler.impl.operator;

import org.apache.sling.scripting.sightly.compiler.expression.SideEffectVisitor;
import org.apache.sling.scripting.sightly.java.compiler.impl.ExpressionTranslator;
import org.apache.sling.scripting.sightly.java.compiler.impl.JavaSource;
import org.apache.sling.scripting.sightly.java.compiler.impl.Type;
import org.apache.sling.scripting.sightly.compiler.expression.ExpressionNode;
import org.apache.sling.scripting.sightly.compiler.expression.nodes.BinaryOperator;

/**
 * Generator for logical operators
 */
public class ComparisonOpGen implements BinaryOpGen {

    private final String javaOperator;
    private final boolean inverted;
    private final String runtimeMethod;

    private static final String METHOD_LEQ = "leq";
    private static final String METHOD_LT = "lt";

    private static final String OBJECT_NAME = BinaryOperator.class.getName();

    public ComparisonOpGen(BinaryOperator operator) {
        switch (operator) {
            case LT: runtimeMethod = METHOD_LT; inverted = false; javaOperator = "<"; break;
            case GT: runtimeMethod = METHOD_LEQ; inverted = true; javaOperator = ">"; break;
            case LEQ: runtimeMethod = METHOD_LEQ; inverted = false; javaOperator = "<="; break;
            case GEQ: runtimeMethod = METHOD_LT; inverted = true; javaOperator = ">="; break;
            default: throw new IllegalArgumentException("Operator is not a comparison operator: " + operator);
        }
    }

    @Override
    public Type returnType(Type left, Type right) {
        return Type.BOOLEAN;
    }

    @Override
    public void generate(JavaSource source, ExpressionTranslator visitor, TypedNode left, TypedNode right) {
        Type type = OpHelper.sameType(left, right);
        if (OpHelper.isNumericType(type)) {
            generateWithOperator(source, visitor, left.getNode(), right.getNode());
        } else {
            generateGeneric(source, visitor, left.getNode(), right.getNode());
        }
    }

    private void generateGeneric(JavaSource source, SideEffectVisitor visitor, ExpressionNode leftNode, ExpressionNode rightNode) {
        if (inverted) {
            source.negation().startExpression();
        }
        source.startMethodCall(OBJECT_NAME, runtimeMethod);
        leftNode.accept(visitor);
        source.separateArgument();
        rightNode.accept(visitor);
        source.endCall();
        if (inverted) {
            source.endExpression();
        }
    }

    private void generateWithOperator(JavaSource source, SideEffectVisitor visitor,
                                      ExpressionNode leftNode, ExpressionNode rightNode) {
        leftNode.accept(visitor);
        source.append(" ").append(javaOperator).append(" ");
        rightNode.accept(visitor);
    }

}