Commons JXPath example source code file (DynaBeanPropertyPointer.java)

This example Commons JXPath source code file (DynaBeanPropertyPointer.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

cannot, dynabean, dynabeanpropertypointer, dynaclass, dynaclass, dynaproperty, illegalargumentexception, jxpathtypeconversionexception, object, object, string, string, util, whole_collection, whole_collection

The Commons JXPath DynaBeanPropertyPointer.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.dynabeans;

import java.util.Arrays;

import org.apache.commons.beanutils.DynaBean;
import org.apache.commons.beanutils.DynaClass;
import org.apache.commons.beanutils.DynaProperty;
import org.apache.commons.jxpath.JXPathTypeConversionException;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.apache.commons.jxpath.ri.model.beans.PropertyPointer;
import org.apache.commons.jxpath.util.TypeUtils;
import org.apache.commons.jxpath.util.ValueUtils;

/**
 * Pointer pointing to a property of a {@link DynaBean}. If the target DynaBean is
 * Serializable, so should this instance be.
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 668329 $ $Date: 2008-06-16 16:59:48 -0500 (Mon, 16 Jun 2008) $
 */
public class DynaBeanPropertyPointer extends PropertyPointer {
    private DynaBean dynaBean;
    private String name;
    private String[] names;

    private static final long serialVersionUID = 2094421509141267239L;

    /**
     * Create a new DynaBeanPropertyPointer.
     * @param parent pointer
     * @param dynaBean pointed
     */
    public DynaBeanPropertyPointer(NodePointer parent, DynaBean dynaBean) {
        super(parent);
        this.dynaBean = dynaBean;
    }

    public Object getBaseValue() {
        return dynaBean.get(getPropertyName());
    }

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

    public int getPropertyCount() {
        return getPropertyNames().length;
    }

    public String[] getPropertyNames() {
        /* @todo do something about the sorting - LIKE WHAT? - MJB */
        if (names == null) {
            DynaClass dynaClass = dynaBean.getDynaClass();
            DynaProperty[] properties = dynaClass.getDynaProperties();
            int count = properties.length;
            boolean hasClass = dynaClass.getDynaProperty("class") != null;
            if (hasClass) {
                count--;       // Exclude "class" from properties
            }
            names = new String[count];
            for (int i = 0, j = 0; i < properties.length; i++) {
                String name = properties[i].getName();
                if (!hasClass || !name.equals("class")) {
                    names[j++] = name;
                }
            }
            Arrays.sort(names);
        }
        return names;
    }

    /**
     * Returns the name of the currently selected property or "*"
     * if none has been selected.
     * @return String
     */
    public String getPropertyName() {
        if (name == null) {
            String[] names = getPropertyNames();
            name = propertyIndex >= 0 && propertyIndex < names.length ? names[propertyIndex] : "*";
        }
        return name;
    }

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

    /**
     * Index of the currently selected property in the list of all
     * properties sorted alphabetically.
     * @return int
     */
    public int getPropertyIndex() {
        if (propertyIndex == UNSPECIFIED_PROPERTY) {
            String[] names = getPropertyNames();
            for (int i = 0; i < names.length; i++) {
                if (names[i].equals(name)) {
                    propertyIndex = i;
                    name = null;
                    break;
                }
            }
        }
        return super.getPropertyIndex();
    }

    /**
     * Index a property by its index in the list of all
     * properties sorted alphabetically.
     * @param index to set
     */
    public void setPropertyIndex(int index) {
        if (propertyIndex != index) {
            super.setPropertyIndex(index);
            name = null;
        }
    }

    /**
     * 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() {
        String name = getPropertyName();
        if (name.equals("*")) {
            return null;
        }

        Object value;
        if (index == WHOLE_COLLECTION) {
            value = ValueUtils.getValue(dynaBean.get(name));
        }
        else if (isIndexedProperty()) {
            // DynaClass at this point is not based on whether
            // the property is indeed indexed, but rather on
            // whether it is an array or List. Therefore
            // the indexed set may fail.
            try {
                value = ValueUtils.getValue(dynaBean.get(name, index));
            }
            catch (ArrayIndexOutOfBoundsException ex) {
                value = null;
            }
            catch (IllegalArgumentException ex) {
                value = dynaBean.get(name);
                value = ValueUtils.getValue(value, index);
            }
        }
        else {
            value = dynaBean.get(name);
            if (ValueUtils.isCollection(value)) {
                value = ValueUtils.getValue(value, index);
            }
            else if (index != 0) {
                value = null;
            }
        }
        return value;
    }

    /**
     * Returns true if the bean has the currently selected property.
     * @return boolean
     */
    protected boolean isActualProperty() {
        DynaClass dynaClass = dynaBean.getDynaClass();
        return dynaClass.getDynaProperty(getPropertyName()) != null;
    }

    /**
     * Learn whether the property referenced is an indexed property.
     * @return boolean
     */
    protected boolean isIndexedProperty() {
        DynaClass dynaClass = dynaBean.getDynaClass();
        DynaProperty property = dynaClass.getDynaProperty(name);
        return property.isIndexed();
    }

    /**
     * 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 to set
     */
    public void setValue(Object value) {
        setValue(index, value);
    }

    public void remove() {
        if (index == WHOLE_COLLECTION) {
            dynaBean.set(getPropertyName(), null);
        }
        else if (isIndexedProperty()) {
            dynaBean.set(getPropertyName(), index, null);
        }
        else if (isCollection()) {
            Object collection = ValueUtils.remove(getBaseValue(), index);
            dynaBean.set(getPropertyName(), collection);
        }
        else if (index == 0) {
            dynaBean.set(getPropertyName(), null);
        }
    }

    /**
     * Set an indexed value.
     * @param index to change
     * @param value to set
     */
    private void setValue(int index, Object value) {
        if (index == WHOLE_COLLECTION) {
            dynaBean.set(getPropertyName(), convert(value, false));
        }
        else if (isIndexedProperty()) {
            dynaBean.set(getPropertyName(), index, convert(value, true));
        }
        else {
            Object baseValue = dynaBean.get(getPropertyName());
            ValueUtils.setValue(baseValue, index, value);
        }
    }


    /**
     * Convert a value to the appropriate property type.
     * @param value to convert
     * @param element whether this should be a collection element.
     * @return conversion result
     */
    private Object convert(Object value, boolean element) {
        DynaClass dynaClass = (DynaClass) dynaBean.getDynaClass();
        DynaProperty property = dynaClass.getDynaProperty(getPropertyName());
        Class type = property.getType();
        if (element) {
            if (type.isArray()) {
                type = type.getComponentType();
            }
            else {
                return value; // No need to convert
            }
        }

        try {
            return TypeUtils.convert(value, type);
        }
        catch (Exception ex) {
            String string = value == null ? "null" : value.getClass().getName();
            throw new JXPathTypeConversionException(
                    "Cannot convert value of class " + string + " to type "
                            + type, ex);
        }
    }
}