Groovy example source code file (NodeList.java)

This example Groovy source code file (NodeList.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 - Groovy tags/keywords

arraylist, groovyruntimeexception, iterator, metaclass, node, node, nodelist, nodelist, object, object, override, string, string, stringbuffer, util

The Groovy NodeList.java source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * Licensed 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 groovy.util;

import groovy.lang.Closure;
import groovy.lang.DelegatingMetaClass;
import groovy.lang.GroovyRuntimeException;
import groovy.lang.GroovySystem;
import groovy.lang.MetaClass;
import groovy.xml.QName;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

/**
 * A List implementation which is returned by queries on a {@link Node}
 * which provides some XPath like helper methods for GPath.
 *
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @author Paul King
 */
public class NodeList extends ArrayList {
    static {
        // wrap the standard MetaClass with the delegate
        setMetaClass(NodeList.class, GroovySystem.getMetaClassRegistry().getMetaClass(NodeList.class));
    }

    public NodeList() {
    }

    public NodeList(Collection collection) {
        super(collection);
    }

    public NodeList(int size) {
        super(size);
    }

    protected static void setMetaClass(final Class nodelistClass, final MetaClass metaClass) {
        final MetaClass newMetaClass = new DelegatingMetaClass(metaClass) {
            @Override
            public Object getAttribute(final Object object, final String attribute) {
                NodeList nl = (NodeList) object;
                Iterator it = nl.iterator();
                List result = new ArrayList();
                while (it.hasNext()) {
                    Node node = (Node) it.next();
                    result.add(node.attributes().get(attribute));
                }
                return result;
            }

            @Override
            public void setAttribute(final Object object, final String attribute, final Object newValue) {
                for (Object o : (NodeList) object) {
                    Node node = (Node) o;
                    node.attributes().put(attribute, newValue);
                }
            }

            @Override
            public Object getProperty(Object object, String property) {
                if (object instanceof NodeList) {
                    NodeList nl = (NodeList) object;
                    return nl.getAt(property);
                }
                return super.getProperty(object, property);
            }
        };
        GroovySystem.getMetaClassRegistry().setMetaClass(nodelistClass, newMetaClass);
    }

    /**
     * Provides lookup of elements by non-namespaced name.
     *
     * @param name the name or shortcut key for nodes of interest
     * @return the nodes of interest which match name
     */
    public NodeList getAt(String name) {
        NodeList answer = new NodeList();
        for (Object child : this) {
            if (child instanceof Node) {
                Node childNode = (Node) child;
                Object temp = childNode.get(name);
                if (temp instanceof Collection) {
                    answer.addAll((Collection) temp);
                } else {
                    answer.add(temp);
                }
            }
        }
        return answer;
    }

    /**
     * Provides lookup of elements by QName.
     *
     * @param name the name or shortcut key for nodes of interest
     * @return the nodes of interest which match name
     */
    public NodeList getAt(QName name) {
        NodeList answer = new NodeList();
        for (Object child : this) {
            if (child instanceof Node) {
                Node childNode = (Node) child;
                NodeList temp = childNode.getAt(name);
                answer.addAll(temp);
            }
        }
        return answer;
    }

    /**
     * Returns the text value of all of the elements in the collection.
     *
     * @return the text value of all the elements in the collection or null
     */
    public String text() {
        String previousText = null;
        StringBuffer buffer = null;
        for (Object child : this) {
            String text = null;
            if (child instanceof String) {
                text = (String) child;
            } else if (child instanceof Node) {
                text = ((Node) child).text();
            }
            if (text != null) {
                if (previousText == null) {
                    previousText = text;
                } else {
                    if (buffer == null) {
                        buffer = new StringBuffer();
                        buffer.append(previousText);
                    }
                    buffer.append(text);
                }
            }
        }
        if (buffer != null) {
            return buffer.toString();
        }
        if (previousText != null) {
            return previousText;
        }
        return "";
    }

    public Node replaceNode(Closure c) {
        if (size() <= 0 || size() > 1) {
            throw new GroovyRuntimeException("replaceNode() can only be used to replace a single node.");
        }
        return ((Node)get(0)).replaceNode(c);
    }

    public void plus(Closure c) {
        for (Object o : this) {
            ((Node) o).plus(c);
        }
    }

}