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Commons JXPath example source code file (CompiledExpression.java)

This example Commons JXPath source code file (CompiledExpression.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

class, compiledexpression, iterator, iterator, object, object, pointer, pointer, string, string, util

The Commons JXPath CompiledExpression.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;

import java.util.Iterator;

/**
 * Represents a compiled XPath. The interpretation of compiled XPaths
 * may be faster, because it bypasses the compilation step. The reference
 * implementation of {@link JXPathContext} also globally caches some of the
 * results of compilation, so the direct use of JXPathContext is not
 * always less efficient than the use of CompiledExpression.
 * <p>
 * Use CompiledExpression only when there is a need to evaluate the
 * same expression multiple times and the CompiledExpression can be
 * conveniently cached.
 * <p>
 * To acquire a CompiledExpression, call {@link JXPathContext#compile
 * JXPathContext.compile}
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
 */
public interface CompiledExpression {

    /**
     * Evaluates the xpath and returns the resulting object. Primitive
     * types are wrapped into objects.
     * @param context to evaluate
     * @return Object
     */
    Object getValue(JXPathContext context);

    /**
     * Evaluates the xpath, converts the result to the specified class and
     * returns the resulting object.
     * @param context to evaluate
     * @param requiredType return type
     * @return Object
     */
    Object getValue(JXPathContext context, Class requiredType);

    /**
     * Modifies the value of the property described by the supplied xpath.
     * Will throw an exception if one of the following conditions occurs:
     * <ul>
     * <li>The xpath does not in fact describe an existing property
     * <li>The property is not writable (no public, non-static set method)
     * </ul>
     * @param context base
     * @param value to set
     */
    void setValue(JXPathContext context, Object value);

    /**
     * Creates intermediate elements of
     * the path by invoking an {@link AbstractFactory}, which should first be
     * installed on the context by calling {@link JXPathContext#setFactory}.
     * @param context base
     * @return Pointer created
     */
    Pointer createPath(JXPathContext context);

    /**
     * The same as setValue, except it creates intermediate elements of
     * the path by invoking an {@link AbstractFactory}, which should first be
     * installed on the context by calling {@link JXPathContext#setFactory}.
     * <p>
     * Will throw an exception if one of the following conditions occurs:
     * <ul>
     * <li>Elements of the xpath aleady exist, by the path does not in
     *  fact describe an existing property
     * <li>The AbstractFactory fails to create an instance for an intermediate
     * element.
     * <li>The property is not writable (no public, non-static set method)
     * </ul>
     * @param context base
     * @param value to set
     * @return Pointer created
     */
    Pointer createPathAndSetValue(JXPathContext context, Object value);

    /**
     * Traverses the xpath and returns a Iterator of all results found
     * for the path. If the xpath matches no properties
     * in the graph, the Iterator will not be null.
     * @param context base
     * @return Iterator
     */
    Iterator iterate(JXPathContext context);

    /**
     * Traverses the xpath and returns a Pointer.
     * A Pointer provides easy access to a property.
     * If the xpath matches no properties
     * in the graph, the pointer will be null.
     * @param context base
     * @param xpath string
     * @return Pointer found
     */
    Pointer getPointer(JXPathContext context, String xpath);

    /**
     * Traverses the xpath and returns an Iterator of Pointers.
     * A Pointer provides easy access to a property.
     * If the xpath matches no properties
     * in the graph, the Iterator be empty, but not null.
     * @param context to iterate
     * @return Iterator<Pointer>
     */
    Iterator iteratePointers(JXPathContext context);

    /**
     * Remove the graph element described by this expression.
     * @param context base
     */
    void removePath(JXPathContext context);

    /**
     * Remove all graph elements described by this expression.
     * @param context base
     */
    void removeAll(JXPathContext context);
}

Other Commons JXPath examples (source code examples)

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

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