/*
* 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);
}
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