Commons JXPath example source code file (BeanPropertyPointer.java)

This example Commons JXPath source code file (BeanPropertyPointer.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

bean, beanpropertypointer, cannot, indexedpropertydescriptor, javabean, jxpathbeaninfo, nodepointer, object, object, propertydescriptor, propertydescriptor, string, uninitialized, uninitialized, whole_collection, whole_collection

The Commons JXPath BeanPropertyPointer.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.model.beans;

import java.beans.IndexedPropertyDescriptor;
import java.beans.PropertyDescriptor;

import org.apache.commons.jxpath.JXPathBeanInfo;
import org.apache.commons.jxpath.JXPathContext;
import org.apache.commons.jxpath.JXPathInvalidAccessException;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.apache.commons.jxpath.util.ValueUtils;

/**
 * Pointer pointing to a property of a JavaBean.
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 670727 $ $Date: 2008-06-23 15:10:38 -0500 (Mon, 23 Jun 2008) $
 */
public class BeanPropertyPointer extends PropertyPointer {
    private static final long serialVersionUID = -6008991447676468786L;

    private static final Object UNINITIALIZED = new Object();

    private String propertyName;
    private JXPathBeanInfo beanInfo;
    private Object baseValue = UNINITIALIZED;
    private Object value = UNINITIALIZED;
    private transient String[] names;
    private transient PropertyDescriptor[] propertyDescriptors;
    private transient PropertyDescriptor propertyDescriptor;

    /**
     * Create a new BeanPropertyPointer.
     * @param parent parent pointer
     * @param beanInfo describes the target property/ies.
     */
    public BeanPropertyPointer(NodePointer parent, JXPathBeanInfo beanInfo) {
        super(parent);
        this.beanInfo = beanInfo;
    }

    /**
     * This type of node is auxiliary.
     * @return true
     */
    public boolean isContainer() {
        return true;
    }

    public int getPropertyCount() {
        if (beanInfo.isAtomic()) {
            return 0;
        }
        return getPropertyDescriptors().length;
    }

    /**
     * Get the names of all properties, sorted alphabetically
     * @return String[]
     */
    public String[] getPropertyNames() {
        if (names == null) {
            PropertyDescriptor[] pds = getPropertyDescriptors();
            names = new String[pds.length];
            for (int i = 0; i < names.length; i++) {
                names[i] = pds[i].getName();
            }
        }
        return names;
    }

    /**
     * Select a property by name.
     * @param propertyName String name
     */
    public void setPropertyName(String propertyName) {
        setPropertyIndex(UNSPECIFIED_PROPERTY);
        this.propertyName = propertyName;
    }

    /**
     * Selects a property by its offset in the alphabetically sorted list.
     * @param index property index
     */
    public void setPropertyIndex(int index) {
        if (propertyIndex != index) {
            super.setPropertyIndex(index);
            propertyName = null;
            propertyDescriptor = null;
            baseValue = UNINITIALIZED;
            value = UNINITIALIZED;
        }
    }

    /**
     * Get the value of the currently selected property.
     * @return Object value
     */
    public Object getBaseValue() {
        if (baseValue == UNINITIALIZED) {
            PropertyDescriptor pd = getPropertyDescriptor();
            if (pd == null) {
                return null;
            }
            baseValue = ValueUtils.getValue(getBean(), pd);
        }
        return baseValue;
    }

    public void setIndex(int index) {
        if (this.index == index) {
            return;
        }
        // When dealing with a scalar, index == 0 is equivalent to
        // WHOLE_COLLECTION, so do not change it.
        if (this.index != WHOLE_COLLECTION
                || index != 0
                || isCollection()) {
            super.setIndex(index);
            value = UNINITIALIZED;
        }
    }

    /**
     * If index == WHOLE_COLLECTION, the value of the property, otherwise
     * the value of the index'th element of the collection represented by the
     * property. If the property is not a collection, index should be zero
     * and the value will be the property itself.
     * @return Object
     */
    public Object getImmediateNode() {
        if (value == UNINITIALIZED) {
            if (index == WHOLE_COLLECTION) {
                value = ValueUtils.getValue(getBaseValue());
            }
            else {
                PropertyDescriptor pd = getPropertyDescriptor();
                if (pd == null) {
                    value = null;
                }
                else {
                    value = ValueUtils.getValue(getBean(), pd, index);
                }
            }
        }
        return value;
    }

    protected boolean isActualProperty() {
        return getPropertyDescriptor() != null;
    }

    public boolean isCollection() {
        PropertyDescriptor pd = getPropertyDescriptor();
        if (pd == null) {
            return false;
        }

        if (pd instanceof IndexedPropertyDescriptor) {
            return true;
        }

        int hint = ValueUtils.getCollectionHint(pd.getPropertyType());
        if (hint == -1) {
            return false;
        }
        if (hint == 1) {
            return true;
        }

        Object value = getBaseValue();
        return value != null && ValueUtils.isCollection(value);
    }

    /**
     * If the property contains a collection, then the length of that
     * collection, otherwise - 1.
     * @return int length
     */
    public int getLength() {
        PropertyDescriptor pd = getPropertyDescriptor();
        if (pd == null) {
            return 1;
        }

        if (pd instanceof IndexedPropertyDescriptor) {
            return ValueUtils.getIndexedPropertyLength(
                getBean(),
                (IndexedPropertyDescriptor) pd);
        }

        int hint = ValueUtils.getCollectionHint(pd.getPropertyType());
        if (hint == -1) {
            return 1;
        }
        return ValueUtils.getLength(getBaseValue());
    }

    /**
     * If index == WHOLE_COLLECTION, change the value of the property, otherwise
     * change the value of the index'th element of the collection
     * represented by the property.
     * @param value value to set
     */
    public void setValue(Object value) {
        PropertyDescriptor pd = getPropertyDescriptor();
        if (pd == null) {
            throw new JXPathInvalidAccessException(
                "Cannot set property: " + asPath() + " - no such property");
        }

        if (index == WHOLE_COLLECTION) {
            ValueUtils.setValue(getBean(), pd, value);
        }
        else {
            ValueUtils.setValue(getBean(), pd, index, value);
        }
        this.value = value;
    }

    public NodePointer createPath(JXPathContext context) {
        if (getImmediateNode() == null) {
            super.createPath(context);
            baseValue = UNINITIALIZED;
            value = UNINITIALIZED;
        }
        return this;
    }

    public void remove() {
        if (index == WHOLE_COLLECTION) {
            setValue(null);
        }
        else if (isCollection()) {
            Object o = getBaseValue();
            Object collection = ValueUtils.remove(getBaseValue(), index);
            if (collection != o) {
                ValueUtils.setValue(getBean(), getPropertyDescriptor(), collection);
            }
        }
        else if (index == 0) {
            index = WHOLE_COLLECTION;
            setValue(null);
        }
    }

    /**
     * Get the name of the currently selected property.
     * @return String property name
     */
    public String getPropertyName() {
        if (propertyName == null) {
            PropertyDescriptor pd = getPropertyDescriptor();
            if (pd != null) {
                propertyName = pd.getName();
            }
        }
        return propertyName != null ? propertyName : "*";
    }

    /**
     * Finds the property descriptor corresponding to the current property
     * index.
     * @return PropertyDescriptor
     */
    private PropertyDescriptor getPropertyDescriptor() {
        if (propertyDescriptor == null) {
            int inx = getPropertyIndex();
            if (inx == UNSPECIFIED_PROPERTY) {
                propertyDescriptor =
                    beanInfo.getPropertyDescriptor(propertyName);
            }
            else {
                PropertyDescriptor[] propertyDescriptors =
                    getPropertyDescriptors();
                if (inx >= 0 && inx < propertyDescriptors.length) {
                    propertyDescriptor = propertyDescriptors[inx];
                }
                else {
                    propertyDescriptor = null;
                }
            }
        }
        return propertyDescriptor;
    }

    /**
     * Get all PropertyDescriptors.
     * @return PropertyDescriptor[]
     */
    protected synchronized PropertyDescriptor[] getPropertyDescriptors() {
        if (propertyDescriptors == null) {
            propertyDescriptors = beanInfo.getPropertyDescriptors();
        }
        return propertyDescriptors;
    }
}