Groovy example source code file (MutualPropertyBinding.java)

This example Groovy source code file (MutualPropertyBinding.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

bindings, closure, closure, fullbinding, fullbinding, mutual, mutualpropertybinding, propertybinding, propertybinding, propertybindings, runtimeexception, triggerbinding, triggerbinding, unsupportedoperationexception

The Groovy MutualPropertyBinding.java source code

/*
 * Copyright 2007-2009 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.binding;

import groovy.lang.Closure;

/**
 * @author <a href="mailto:shemnon@yahoo.com">Danno Ferrin
 * @version $Revision: 10897 $
 * @since Groovy 1.6
 */

public class MutualPropertyBinding implements FullBinding {

    boolean bound;

    PropertyBinding sourceBinding;
    PropertyBinding targetBinding;
    Closure validator;
    Closure converter;
    Closure reverseConverter;

    Closure triggerFactory;

    TriggerBinding forwardTriggerBinding;
    FullBinding forwardBinding;
    TriggerBinding reverseTriggerBinding;
    FullBinding reverseBinding;

    MutualPropertyBinding(TriggerBinding forwardTrigger, PropertyBinding source, PropertyBinding target, Closure triggerFactory) {
        // order matters here!
        this.triggerFactory = triggerFactory;
        sourceBinding = source;
        forwardTriggerBinding = forwardTrigger;
        setTargetBinding(target);
        rebuildBindings();
    }

    public SourceBinding getSourceBinding() {
        return sourceBinding;
    }

    public TargetBinding getTargetBinding() {
        return targetBinding;
    }

    public void setSourceBinding(SourceBinding sourceBinding) {
        try {
            if (sourceBinding == null) {
                forwardTriggerBinding = null;
            } else {
                forwardTriggerBinding = (TriggerBinding) triggerFactory.call(sourceBinding);
            }
            this.sourceBinding = (PropertyBinding) sourceBinding;
        } catch (RuntimeException re) {
            throw new UnsupportedOperationException("Mutual Bindings may only change source bindings to other PropertyBindings");
        }
        rebuildBindings();
    }

    public void setTargetBinding(TargetBinding targetBinding) {
        try {
            if (targetBinding == null) {
                reverseTriggerBinding = null;
            } else {
                reverseTriggerBinding = (TriggerBinding) triggerFactory.call(targetBinding);
            }
            this.targetBinding = (PropertyBinding) targetBinding;
        } catch (RuntimeException re) {
            throw new UnsupportedOperationException("Mutual Bindings may only change target bindings to other PropertyBindings");
        }
        rebuildBindings();
    }

    public void setValidator(Closure validator) {
        this.validator = validator;
        rebuildBindings();
    }

    public Closure getValidator() {
        return validator;
    }

    public void setConverter(Closure converter) {
        this.converter = converter;
        rebuildBindings();
    }

    public Closure getConverter() {
        return converter;
    }

    public void setReverseConverter(Closure reverseConverter) {
       this.reverseConverter = reverseConverter;
        rebuildBindings();
    }

    public Closure getReverseConverter() {
        return reverseConverter;
    }

    protected void rebuildBindings() {
        // tear stuff down, even if we are half built
        if (bound) {
            if (forwardBinding != null) {
                forwardBinding.unbind();
            }
            if (reverseBinding != null) {
                reverseBinding.unbind();
            }
        }

        // check for all pieces, if we don't have the triad quit silently
        if (forwardTriggerBinding == null || sourceBinding == null || reverseTriggerBinding == null || targetBinding == null) {
            return;
        }

        // build the pieces
        forwardBinding = forwardTriggerBinding.createBinding(sourceBinding, targetBinding);
        reverseBinding = reverseTriggerBinding.createBinding(targetBinding, sourceBinding);

        // add the ancillary pieces
        if ((converter != null) && (reverseConverter != null)) {
            forwardBinding.setConverter(converter);
            reverseBinding.setConverter(reverseConverter);
        }
        if (validator != null) {
            forwardBinding.setValidator(validator);
        }

        // rebind if we were bound
        if (bound) {
            forwardBinding.bind();
            reverseBinding.bind();
        }

    }

    public void bind() {
        if (!bound) {
            bound = true;
            //guard checks

            // both converter and reverseConverter must be set or not
            if ((converter == null) != (reverseConverter == null)) {
                throw new RuntimeException("Both converter or reverseConverter must be set or unset to bind.  Only "
                        + ((converter != null) ? "converter": "reverseConverter") + " is set.");
            }
            // don't bind if we are half set up, quietly stop
            if (forwardBinding == null || reverseBinding == null) {
                // don't worry about the bind state, if the binding
                // is completed we will bind in rebuild
                return;
            }

            forwardBinding.bind();
            reverseBinding.bind();
        }
    }

    public void unbind() {
        if (bound) {
            forwardBinding.unbind();
            reverseBinding.unbind();
            bound = false;
        }
    }

    public void rebind() {
        if (bound) {
            unbind();
            bind();
        }
    }

    public void update() {
        forwardBinding.update();
    }

    public void reverseUpdate() {
        reverseBinding.update();
    }
}