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Groovy example source code file (PluginDefaultGroovyMethods.java)

This example Groovy source code file (PluginDefaultGroovyMethods.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

charsequence, defaultgroovymethodssupport, emptyrange, intrange, method, method, no_args, no_args, object, object, plugindefaultgroovymethods, rangeinfo, reflection, string, string, util

The Groovy PluginDefaultGroovyMethods.java source code

/*
 * Copyright 2003-2007 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 org.codehaus.groovy.vmplugin.v5;

import groovy.lang.IntRange;
import groovy.lang.EmptyRange;
import org.codehaus.groovy.runtime.InvokerHelper;
import org.codehaus.groovy.runtime.DefaultGroovyMethodsSupport;

import java.util.Arrays;
import java.lang.reflect.Method;

/**
 * This class defines new Java 5 specific groovy methods which extend the normal
 * JDK classes inside the Groovy environment. Static methods are used with the
 * first parameter the destination class.
 */
public class PluginDefaultGroovyMethods extends DefaultGroovyMethodsSupport {
    private static final Object[] NO_ARGS = new Object[0];

    /**
     * This method is called by the ++ operator for enums. It will invoke
     * Groovy's default next behaviour for enums do not have their own
     * next method (Only works with JDK1.5 or later).
     *
     * @param self an Enum
     * @return the next defined enum from the enum class
     */
    public static Object next(Enum self) {
        final Method[] methods = self.getClass().getMethods();
        for (int i = 0; i < methods.length; i++) {
            Method method = methods[i];
            if (method.getName().equals("next") && method.getParameterTypes().length == 0) {
                return InvokerHelper.invokeMethod(self, "next", NO_ARGS);
            }
        }
        Object[] values = (Object[]) InvokerHelper.invokeStaticMethod(self.getClass(), "values", NO_ARGS);
        int index = Arrays.asList(values).indexOf(self);
        return values[index < values.length - 1 ? index + 1 : 0];
    }

    /**
     * This method is called by the -- operator for enums. It will invoke
     * Groovy's default previous behaviour for enums that do not have
     * their own previous method (Only works with JDK1.5 or later).
     *
     * @param self an Enum
     * @return the previous defined enum from the enum class
     */
    public static Object previous(Enum self) {
        final Method[] methods = self.getClass().getMethods();
        for (int i = 0; i < methods.length; i++) {
            Method method = methods[i];
            if (method.getName().equals("previous") && method.getParameterTypes().length == 0) {
                return InvokerHelper.invokeMethod(self, "previous", NO_ARGS);
            }
        }
        Object[] values = (Object[]) InvokerHelper.invokeStaticMethod(self.getClass(), "values", NO_ARGS);
        int index = Arrays.asList(values).indexOf(self);
        return values[index > 0 ? index - 1 : values.length - 1];
    }

    /**
     * Standard Groovy size() method for StringBuilders
     * (Only works with JDK1.5 or later).
     *
     * @param builder a StringBuilder
     * @return the length of the StringBuilder
     */
    public static int size(StringBuilder builder) {
        return builder.length();
    }

    /**
     * Overloads the left shift operator to provide an easy way to append multiple
     * objects as string representations to a StringBuilder (Only works with JDK1.5 or later).
     *
     * @param self  a StringBuilder
     * @param value a value to append
     * @return the StringBuilder on which this operation was invoked
     */
    public static StringBuilder leftShift(StringBuilder self, Object value) {
        if (value instanceof CharSequence)
            return self.append((CharSequence)value);
        else
            return self.append(value);
    }

    /**
     * Support the range subscript operator for StringBuilder (Only works with JDK1.5 or later).
     * Index values are treated as characters within the builder.
     *
     * @param self  a StringBuilder
     * @param range a Range
     * @param value the object that's toString() will be inserted
     */
    public static void putAt(StringBuilder self, IntRange range, Object value) {
        RangeInfo info = subListBorders(self.length(), range);
        self.replace(info.from, info.to, value.toString());
    }

    /**
     * Support the range subscript operator for StringBuilder (Only works with JDK1.5 or later).
     *
     * @param self  a StringBuilder
     * @param range a Range
     * @param value the object that's toString() will be inserted
     */
    public static void putAt(StringBuilder self, EmptyRange range, Object value) {
        RangeInfo info = subListBorders(self.length(), range);
        self.replace(info.from, info.to, value.toString());
    }

    /**
     * Appends a String to this StringBuilder (Only works with JDK1.5 or later).
     *
     * @param self  a StringBuilder
     * @param value a String
     * @return a String
     */
    public static String plus(StringBuilder self, String value) {
        return self + value;
    }

}

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