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Commons JXPath example source code file (TreeCompiler.java)

This example Commons JXPath source code file (TreeCompiler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons JXPath tags/keywords

constant, coreoperationnegate, expression, expression, locationpath, nodenametest, nodenametest, nodetest, object, object, qname, step, step, string

The Commons JXPath TreeCompiler.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.jxpath.ri.compiler;

import org.apache.commons.jxpath.ri.Compiler;
import org.apache.commons.jxpath.ri.QName;

/**
 * @author Dmitri Plotnikov
 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
 */
public class TreeCompiler implements Compiler {

    private static final QName QNAME_NAME = new QName(null, "name");

    public Object number(String value) {
        return new Constant(new Double(value));
    }

    public Object literal(String value) {
        return new Constant(value);
    }

    public Object qname(String prefix, String name) {
        return new QName(prefix, name);
    }

    public Object sum(Object[] arguments) {
        return new CoreOperationAdd(toExpressionArray(arguments));
    }

    public Object minus(Object left, Object right) {
        return new CoreOperationSubtract(
            (Expression) left,
            (Expression) right);
    }

    public Object multiply(Object left, Object right) {
        return new CoreOperationMultiply((Expression) left, (Expression) right);
    }

    public Object divide(Object left, Object right) {
        return new CoreOperationDivide((Expression) left, (Expression) right);
    }

    public Object mod(Object left, Object right) {
        return new CoreOperationMod((Expression) left, (Expression) right);
    }

    public Object lessThan(Object left, Object right) {
        return new CoreOperationLessThan((Expression) left, (Expression) right);
    }

    public Object lessThanOrEqual(Object left, Object right) {
        return new CoreOperationLessThanOrEqual(
            (Expression) left,
            (Expression) right);
    }

    public Object greaterThan(Object left, Object right) {
        return new CoreOperationGreaterThan(
            (Expression) left,
            (Expression) right);
    }

    public Object greaterThanOrEqual(Object left, Object right) {
        return new CoreOperationGreaterThanOrEqual(
            (Expression) left,
            (Expression) right);
    }

    public Object equal(Object left, Object right) {
        return isNameAttributeTest((Expression) left)
                ? new NameAttributeTest((Expression) left, (Expression) right)
                : new CoreOperationEqual((Expression) left, (Expression) right);
    }

    public Object notEqual(Object left, Object right) {
        return new CoreOperationNotEqual((Expression) left, (Expression) right);
    }

    public Object minus(Object argument) {
        return new CoreOperationNegate((Expression) argument);
    }

    public Object variableReference(Object qName) {
        return new VariableReference((QName) qName);
    }

    public Object function(int code, Object[] args) {
        return new CoreFunction(code, toExpressionArray(args));
    }

    public Object function(Object name, Object[] args) {
        return new ExtensionFunction((QName) name, toExpressionArray(args));
    }

    public Object and(Object[] arguments) {
        return new CoreOperationAnd(toExpressionArray(arguments));
    }

    public Object or(Object[] arguments) {
        return new CoreOperationOr(toExpressionArray(arguments));
    }

    public Object union(Object[] arguments) {
        return new CoreOperationUnion(toExpressionArray(arguments));
    }

    public Object locationPath(boolean absolute, Object[] steps) {
        return new LocationPath(absolute, toStepArray(steps));
    }

    public Object expressionPath(Object expression, Object[] predicates,
            Object[] steps) {
        return new ExpressionPath(
            (Expression) expression,
            toExpressionArray(predicates),
            toStepArray(steps));
    }

    public Object nodeNameTest(Object qname) {
        return new NodeNameTest((QName) qname);
    }

    public Object nodeTypeTest(int nodeType) {
        return new NodeTypeTest(nodeType);
    }

    public Object processingInstructionTest(String instruction) {
        return new ProcessingInstructionTest(instruction);
    }

    public Object step(int axis, Object nodeTest, Object[] predicates) {
        return new Step(
            axis,
            (NodeTest) nodeTest,
            toExpressionArray(predicates));
    }

    /**
     * Get an Object[] as an Expression[].
     * @param array Object[]
     * @return Expression[]
     */
    private Expression[] toExpressionArray(Object[] array) {
        Expression[] expArray = null;
        if (array != null) {
            expArray = new Expression[array.length];
            for (int i = 0; i < expArray.length; i++) {
                expArray[i] = (Expression) array[i];
            }
        }
        return expArray;
    }

    /**
     * Get an Object[] as a Step[].
     * @param array Object[]
     * @return Step[]
     */
    private Step[] toStepArray(Object[] array) {
        Step[] stepArray = null;
        if (array != null) {
            stepArray = new Step[array.length];
            for (int i = 0; i < stepArray.length; i++) {
                stepArray[i] = (Step) array[i];
            }
        }
        return stepArray;
    }

    /**
     * Learn whether arg is a name attribute test.
     * @param arg Expression to test
     * @return boolean
     */
    private boolean isNameAttributeTest(Expression arg) {
        if (!(arg instanceof LocationPath)) {
            return false;
        }

        Step[] steps = ((LocationPath) arg).getSteps();
        if (steps.length != 1) {
            return false;
        }
        if (steps[0].getAxis() != Compiler.AXIS_ATTRIBUTE) {
            return false;
        }
        NodeTest test = steps[0].getNodeTest();
        if (!(test instanceof NodeNameTest)) {
            return false;
        }
        if (!((NodeNameTest) test).getNodeName().equals(QNAME_NAME)) {
            return false;
        }
        return true;
    }
}

Other Commons JXPath examples (source code examples)

Here is a short list of links related to this Commons JXPath TreeCompiler.java source code file:

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