/*
* 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.wicket.extensions.wizard;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.apache.wicket.util.io.IClusterable;
import org.apache.wicket.util.collections.ArrayListStack;
/**
* Default implementation of {@link IWizardModel}, which models a semi-static wizard. This means
* that all steps should be known upfront, and added to the model on construction. Steps can be
* optional by using {@link ICondition}. The wizard is initialized with a wizard model through
* calling method {@link Wizard#init(IWizardModel)}.
* <p>
* Steps can be added to this model directly using either the {@link #add(IWizardStep) normal add
* method} or {@link #add(IWizardStep, ICondition) the conditional add method}.
* </p>
*
* <p>
* <a href="https://wizard-framework.dev.java.net/">Swing Wizard Framework</a> served as a valuable
* source of inspiration.
* </p>
*
* @author Eelco Hillenius
*/
public class WizardModel extends AbstractWizardModel
{
/**
* Interface for conditional displaying of wizard steps.
*/
public interface ICondition extends IClusterable
{
/**
* Evaluates the current state and returns whether the step that is coupled to this
* condition is available.
*
* @return True if the step this condition is coupled to is available, false otherwise
*/
public boolean evaluate();
}
/**
* Condition that always evaluates true.
*/
public static final ICondition TRUE = new ICondition()
{
private static final long serialVersionUID = 1L;
/**
* Always returns true.
*
* @return True
*/
@Override
public boolean evaluate()
{
return true;
}
};
private static final long serialVersionUID = 1L;
/** The currently active step. */
private IWizardStep activeStep;
/** Conditions with steps. */
private final List<ICondition> conditions = new ArrayList<>();
/** State history. */
private final ArrayListStack<IWizardStep> history = new ArrayListStack<>();
/** The wizard steps. */
private final List<IWizardStep> steps = new ArrayList<>();
/**
* Construct.
*/
public WizardModel()
{
}
/**
* Adds the next step to the wizard. If the {@link WizardStep} implements {@link ICondition},
* then this method is equivalent to calling {@link #add(IWizardStep, ICondition) add(step,
* (ICondition)step)}.
*
* @param step
* the step to added.
*/
public void add(final IWizardStep step)
{
if (step instanceof ICondition)
{
add(step, (ICondition)step);
}
else
{
add(step, TRUE);
}
}
/**
* Adds an optional step to the model. The step will only be displayed if the specified
* condition is met.
*
* @param step
* The step to add
* @param condition
* the {@link ICondition} under which it should be included in the wizard.
*/
public void add(final IWizardStep step, final ICondition condition)
{
steps.add(step);
conditions.add(condition);
}
/**
* Gets the current active step the wizard should display.
*
* @return the active step.
*/
@Override
public final IWizardStep getActiveStep()
{
return activeStep;
}
/**
* Checks if the last button should be enabled.
*
* @return <tt>true</tt> if the last button should be enabled, <tt>false</tt> otherwise.
* @see IWizardModel#isLastVisible
*/
@Override
public boolean isLastAvailable()
{
return allStepsComplete() && !isLastStep(activeStep);
}
/**
* @see org.apache.wicket.extensions.wizard.IWizardModel#isLastStep(org.apache.wicket.extensions.wizard.IWizardStep)
*/
@Override
public boolean isLastStep(final IWizardStep step)
{
return findLastStep().equals(step);
}
/**
* Checks if the next button should be enabled.
*
* @return <tt>true</tt> if the next button should be enabled, <tt>false</tt> otherwise.
*/
@Override
public boolean isNextAvailable()
{
return activeStep.isComplete() && !isLastStep(activeStep);
}
/**
* Checks if the previous button should be enabled.
*
* @return <tt>true</tt> if the previous button should be enabled, <tt>false</tt> otherwise.
*/
@Override
public boolean isPreviousAvailable()
{
return !history.isEmpty();
}
/**
* @see org.apache.wicket.extensions.wizard.IWizardModel#last()
*/
@Override
public void last()
{
history.push(getActiveStep());
IWizardStep lastStep = findLastStep();
setActiveStep(lastStep);
}
/**
* @see org.apache.wicket.extensions.wizard.IWizardModel#next()
*/
@Override
public void next()
{
history.push(getActiveStep());
IWizardStep step = findNextVisibleStep();
setActiveStep(step);
}
/**
* @see org.apache.wicket.extensions.wizard.IWizardModel#previous()
*/
@Override
public void previous()
{
IWizardStep step = history.pop();
setActiveStep(step);
}
/**
* @see org.apache.wicket.extensions.wizard.IWizardModel#reset()
*/
@Override
public void reset()
{
history.clear();
activeStep = null;
for (IWizardStep step : steps)
{
step.init(this);
}
setActiveStep(findNextVisibleStep());
}
/**
* Sets the active step.
*
* @param step
* the new active step step.
*/
public void setActiveStep(final IWizardStep step)
{
if ((activeStep != null) && (step != null) && activeStep.equals(step))
{
return;
}
activeStep = step;
fireActiveStepChanged(step);
}
/**
* @see IWizardModel#stepIterator()
*/
@Override
public final Iterator<IWizardStep> stepIterator()
{
return steps.iterator();
}
/**
* Returns true if all the steps in the wizard return <tt>true</tt> from
* {@link IWizardStep#isComplete}. This is primarily used to determine if the last button can be
* enabled.
*
* @return <tt>true</tt> if all the steps in the wizard are complete, <tt>false</tt> otherwise.
*/
protected final boolean allStepsComplete()
{
for (IWizardStep step : steps)
{
if (!step.isComplete())
{
return false;
}
}
return true;
}
/**
* Finds the last step in this model.
*
* @return The last step
*/
protected final IWizardStep findLastStep()
{
for (int i = conditions.size() - 1; i >= 0; i--)
{
ICondition condition = conditions.get(i);
if (condition.evaluate())
{
return steps.get(i);
}
}
throw new IllegalStateException("Wizard contains no visible steps");
}
/**
* Finds the next visible step based on the active step.
*
* @return The next visible step based on the active step
*/
protected final IWizardStep findNextVisibleStep()
{
int startIndex = (activeStep == null) ? 0 : steps.indexOf(activeStep) + 1;
for (int i = startIndex; i < conditions.size(); i++)
{
ICondition condition = conditions.get(i);
if (condition.evaluate())
{
return steps.get(i);
}
}
throw new IllegalStateException("Wizard contains no more visible steps");
}
/**
* Gets conditions.
*
* @return unmodifiable list of conditions
*/
public List<ICondition> getConditions()
{
return Collections.unmodifiableList(conditions);
}
}