Java tutorial
/* * Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javafx.beans.binding; import java.lang.ref.WeakReference; import javafx.beans.InvalidationListener; import javafx.beans.NamedArg; import javafx.beans.Observable; import javafx.beans.value.ObservableBooleanValue; import javafx.beans.value.ObservableDoubleValue; import javafx.beans.value.ObservableFloatValue; import javafx.beans.value.ObservableLongValue; import javafx.beans.value.ObservableNumberValue; import javafx.beans.value.ObservableObjectValue; import javafx.beans.value.ObservableStringValue; import javafx.beans.value.ObservableValue; import javafx.collections.FXCollections; import javafx.collections.ObservableList; import com.sun.javafx.binding.DoubleConstant; import com.sun.javafx.binding.FloatConstant; import com.sun.javafx.binding.IntegerConstant; import com.sun.javafx.binding.Logging; import com.sun.javafx.binding.LongConstant; /** * Starting point for a binding that calculates a ternary expression. * <p> * A ternary expression has the basic form * {@code new When(cond).then(value1).otherwise(value2);}. The expression * {@code cond} needs to be a {@link javafx.beans.value.ObservableBooleanValue}. * Based on the value of {@code cond}, the binding contains the value of * {@code value1} (if {@code cond.getValue() == true}) or {@code value2} (if * {@code cond.getValue() == false}). The values {@code value1} and * {@code value2} have to be of the same type. They can be constant values or * implementations of {@link javafx.beans.value.ObservableValue}. * @since JavaFX 2.0 */ public class When { private final ObservableBooleanValue condition; /** * The constructor of {@code When}. * * @param condition * the condition of the ternary expression */ public When(final @NamedArg("condition") ObservableBooleanValue condition) { if (condition == null) { throw new NullPointerException("Condition must be specified."); } this.condition = condition; } private static class WhenListener implements InvalidationListener { private final ObservableBooleanValue condition; private final ObservableValue<?> thenValue; private final ObservableValue<?> otherwiseValue; private final WeakReference<Binding<?>> ref; private WhenListener(Binding<?> binding, ObservableBooleanValue condition, ObservableValue<?> thenValue, ObservableValue<?> otherwiseValue) { this.ref = new WeakReference<Binding<?>>(binding); this.condition = condition; this.thenValue = thenValue; this.otherwiseValue = otherwiseValue; } @Override public void invalidated(Observable observable) { final Binding<?> binding = ref.get(); if (binding == null) { condition.removeListener(this); if (thenValue != null) { thenValue.removeListener(this); } if (otherwiseValue != null) { otherwiseValue.removeListener(this); } } else { // short-circuit invalidation. This Binding becomes // only invalid if the condition changes or the // active branch. if (condition.equals(observable) || (binding.isValid() && (condition.get() == observable.equals(thenValue)))) { binding.invalidate(); } } } } private static NumberBinding createNumberCondition(final ObservableBooleanValue condition, final ObservableNumberValue thenValue, final ObservableNumberValue otherwiseValue) { if ((thenValue instanceof ObservableDoubleValue) || (otherwiseValue instanceof ObservableDoubleValue)) { return new DoubleBinding() { final InvalidationListener observer = new WhenListener(this, condition, thenValue, otherwiseValue); { condition.addListener(observer); thenValue.addListener(observer); otherwiseValue.addListener(observer); } @Override public void dispose() { condition.removeListener(observer); thenValue.removeListener(observer); otherwiseValue.removeListener(observer); } @Override protected double computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? thenValue.doubleValue() : otherwiseValue.doubleValue(); } @Override public ObservableList<ObservableValue<?>> getDependencies() { return FXCollections.unmodifiableObservableList(FXCollections .<ObservableValue<?>>observableArrayList(condition, thenValue, otherwiseValue)); } }; } else if ((thenValue instanceof ObservableFloatValue) || (otherwiseValue instanceof ObservableFloatValue)) { return new FloatBinding() { final InvalidationListener observer = new WhenListener(this, condition, thenValue, otherwiseValue); { condition.addListener(observer); thenValue.addListener(observer); otherwiseValue.addListener(observer); } @Override public void dispose() { condition.removeListener(observer); thenValue.removeListener(observer); otherwiseValue.removeListener(observer); } @Override protected float computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? thenValue.floatValue() : otherwiseValue.floatValue(); } @Override public ObservableList<ObservableValue<?>> getDependencies() { return FXCollections.unmodifiableObservableList(FXCollections .<ObservableValue<?>>observableArrayList(condition, thenValue, otherwiseValue)); } }; } else if ((thenValue instanceof ObservableLongValue) || (otherwiseValue instanceof ObservableLongValue)) { return new LongBinding() { final InvalidationListener observer = new WhenListener(this, condition, thenValue, otherwiseValue); { condition.addListener(observer); thenValue.addListener(observer); otherwiseValue.addListener(observer); } @Override public void dispose() { condition.removeListener(observer); thenValue.removeListener(observer); otherwiseValue.removeListener(observer); } @Override protected long computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? thenValue.longValue() : otherwiseValue.longValue(); } @Override public ObservableList<ObservableValue<?>> getDependencies() { return FXCollections.unmodifiableObservableList(FXCollections .<ObservableValue<?>>observableArrayList(condition, thenValue, otherwiseValue)); } }; } else { return new IntegerBinding() { final InvalidationListener observer = new WhenListener(this, condition, thenValue, otherwiseValue); { condition.addListener(observer); thenValue.addListener(observer); otherwiseValue.addListener(observer); } @Override public void dispose() { condition.removeListener(observer); thenValue.removeListener(observer); otherwiseValue.removeListener(observer); } @Override protected int computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? thenValue.intValue() : otherwiseValue.intValue(); } @Override public ObservableList<ObservableValue<?>> getDependencies() { return FXCollections.unmodifiableObservableList(FXCollections .<ObservableValue<?>>observableArrayList(condition, thenValue, otherwiseValue)); } }; } } /** * If-then-else expression returning a number. * @since JavaFX 2.0 */ public class NumberConditionBuilder { private ObservableNumberValue thenValue; private NumberConditionBuilder(final ObservableNumberValue thenValue) { this.thenValue = thenValue; } /** * Defines the {@link javafx.beans.value.ObservableNumberValue} which * value is returned by the ternary expression if the condition is * {@code false}. * * @param otherwiseValue * the value * @return the complete {@link DoubleBinding} */ public NumberBinding otherwise(ObservableNumberValue otherwiseValue) { if (otherwiseValue == null) { throw new NullPointerException("Value needs to be specified"); } return When.createNumberCondition(condition, thenValue, otherwiseValue); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link DoubleBinding} */ public DoubleBinding otherwise(double otherwiseValue) { return (DoubleBinding) otherwise(DoubleConstant.valueOf(otherwiseValue)); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link NumberBinding} */ public NumberBinding otherwise(float otherwiseValue) { return otherwise(FloatConstant.valueOf(otherwiseValue)); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link NumberBinding} */ public NumberBinding otherwise(long otherwiseValue) { return otherwise(LongConstant.valueOf(otherwiseValue)); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link NumberBinding} */ public NumberBinding otherwise(int otherwiseValue) { return otherwise(IntegerConstant.valueOf(otherwiseValue)); } } /** * Defines the {@link javafx.beans.value.ObservableNumberValue} which value * is returned by the ternary expression if the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public NumberConditionBuilder then(final ObservableNumberValue thenValue) { if (thenValue == null) { throw new NullPointerException("Value needs to be specified"); } return new NumberConditionBuilder(thenValue); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public NumberConditionBuilder then(double thenValue) { return new NumberConditionBuilder(DoubleConstant.valueOf(thenValue)); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public NumberConditionBuilder then(float thenValue) { return new NumberConditionBuilder(FloatConstant.valueOf(thenValue)); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public NumberConditionBuilder then(long thenValue) { return new NumberConditionBuilder(LongConstant.valueOf(thenValue)); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public NumberConditionBuilder then(int thenValue) { return new NumberConditionBuilder(IntegerConstant.valueOf(thenValue)); } /** * If-then-else expression returning Boolean. */ private class BooleanCondition extends BooleanBinding { private final ObservableBooleanValue trueResult; private final boolean trueResultValue; private final ObservableBooleanValue falseResult; private final boolean falseResultValue; private final InvalidationListener observer; private BooleanCondition(final ObservableBooleanValue then, final ObservableBooleanValue otherwise) { this.trueResult = then; this.trueResultValue = false; this.falseResult = otherwise; this.falseResultValue = false; this.observer = new WhenListener(this, condition, then, otherwise); condition.addListener(observer); then.addListener(observer); otherwise.addListener(observer); } private BooleanCondition(final boolean then, final ObservableBooleanValue otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = otherwise; this.falseResultValue = false; this.observer = new WhenListener(this, condition, null, otherwise); condition.addListener(observer); otherwise.addListener(observer); } private BooleanCondition(final ObservableBooleanValue then, final boolean otherwise) { this.trueResult = then; this.trueResultValue = false; this.falseResult = null; this.falseResultValue = otherwise; this.observer = new WhenListener(this, condition, then, null); condition.addListener(observer); then.addListener(observer); } private BooleanCondition(final boolean then, final boolean otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = null; this.falseResultValue = otherwise; this.observer = null; super.bind(condition); } @Override protected boolean computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? (trueResult != null ? trueResult.get() : trueResultValue) : (falseResult != null ? falseResult.get() : falseResultValue); } @Override public void dispose() { if (observer == null) { super.unbind(condition); } else { condition.removeListener(observer); if (trueResult != null) { trueResult.removeListener(observer); } if (falseResult != null) { falseResult.removeListener(observer); } } } @Override public ObservableList<ObservableValue<?>> getDependencies() { assert condition != null; final ObservableList<ObservableValue<?>> seq = FXCollections .<ObservableValue<?>>observableArrayList(condition); if (trueResult != null) { seq.add(trueResult); } if (falseResult != null) { seq.add(falseResult); } return FXCollections.unmodifiableObservableList(seq); } } /** * An intermediate class needed while assembling the ternary expression. It * should not be used in another context. * @since JavaFX 2.0 */ public class BooleanConditionBuilder { private ObservableBooleanValue trueResult; private boolean trueResultValue; private BooleanConditionBuilder(final ObservableBooleanValue thenValue) { this.trueResult = thenValue; } private BooleanConditionBuilder(final boolean thenValue) { this.trueResultValue = thenValue; } /** * Defines the {@link javafx.beans.value.ObservableBooleanValue} which * value is returned by the ternary expression if the condition is * {@code false}. * * @param otherwiseValue * the value * @return the complete {@link BooleanBinding} */ public BooleanBinding otherwise(final ObservableBooleanValue otherwiseValue) { if (otherwiseValue == null) { throw new NullPointerException("Value needs to be specified"); } if (trueResult != null) return new BooleanCondition(trueResult, otherwiseValue); else return new BooleanCondition(trueResultValue, otherwiseValue); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link BooleanBinding} */ public BooleanBinding otherwise(final boolean otherwiseValue) { if (trueResult != null) return new BooleanCondition(trueResult, otherwiseValue); else return new BooleanCondition(trueResultValue, otherwiseValue); } } /** * Defines the {@link javafx.beans.value.ObservableBooleanValue} which value * is returned by the ternary expression if the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public BooleanConditionBuilder then(final ObservableBooleanValue thenValue) { if (thenValue == null) { throw new NullPointerException("Value needs to be specified"); } return new BooleanConditionBuilder(thenValue); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public BooleanConditionBuilder then(final boolean thenValue) { return new BooleanConditionBuilder(thenValue); } /** * If-then-else expression returning String. */ private class StringCondition extends StringBinding { private final ObservableStringValue trueResult; private final String trueResultValue; private final ObservableStringValue falseResult; private final String falseResultValue; private final InvalidationListener observer; private StringCondition(final ObservableStringValue then, final ObservableStringValue otherwise) { this.trueResult = then; this.trueResultValue = ""; this.falseResult = otherwise; this.falseResultValue = ""; this.observer = new WhenListener(this, condition, then, otherwise); condition.addListener(observer); then.addListener(observer); otherwise.addListener(observer); } private StringCondition(final String then, final ObservableStringValue otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = otherwise; this.falseResultValue = ""; this.observer = new WhenListener(this, condition, null, otherwise); condition.addListener(observer); otherwise.addListener(observer); } private StringCondition(final ObservableStringValue then, final String otherwise) { this.trueResult = then; this.trueResultValue = ""; this.falseResult = null; this.falseResultValue = otherwise; this.observer = new WhenListener(this, condition, then, null); condition.addListener(observer); then.addListener(observer); } private StringCondition(final String then, final String otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = null; this.falseResultValue = otherwise; this.observer = null; super.bind(condition); } @Override protected String computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? (trueResult != null ? trueResult.get() : trueResultValue) : (falseResult != null ? falseResult.get() : falseResultValue); } @Override public void dispose() { if (observer == null) { super.unbind(condition); } else { condition.removeListener(observer); if (trueResult != null) { trueResult.removeListener(observer); } if (falseResult != null) { falseResult.removeListener(observer); } } } @Override public ObservableList<ObservableValue<?>> getDependencies() { assert condition != null; final ObservableList<ObservableValue<?>> seq = FXCollections .<ObservableValue<?>>observableArrayList(condition); if (trueResult != null) { seq.add(trueResult); } if (falseResult != null) { seq.add(falseResult); } return FXCollections.unmodifiableObservableList(seq); } } /** * An intermediate class needed while assembling the ternary expression. It * should not be used in another context. * @since JavaFX 2.0 */ public class StringConditionBuilder { private ObservableStringValue trueResult; private String trueResultValue; private StringConditionBuilder(final ObservableStringValue thenValue) { this.trueResult = thenValue; } private StringConditionBuilder(final String thenValue) { this.trueResultValue = thenValue; } /** * Defines the {@link javafx.beans.value.ObservableStringValue} which * value is returned by the ternary expression if the condition is * {@code false}. * * @param otherwiseValue * the value * @return the complete {@link StringBinding} */ public StringBinding otherwise(final ObservableStringValue otherwiseValue) { if (trueResult != null) return new StringCondition(trueResult, otherwiseValue); else return new StringCondition(trueResultValue, otherwiseValue); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link StringBinding} */ public StringBinding otherwise(final String otherwiseValue) { if (trueResult != null) return new StringCondition(trueResult, otherwiseValue); else return new StringCondition(trueResultValue, otherwiseValue); } } /** * Defines the {@link javafx.beans.value.ObservableStringValue} which value * is returned by the ternary expression if the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public StringConditionBuilder then(final ObservableStringValue thenValue) { if (thenValue == null) { throw new NullPointerException("Value needs to be specified"); } return new StringConditionBuilder(thenValue); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public StringConditionBuilder then(final String thenValue) { return new StringConditionBuilder(thenValue); } /** * If-then-else expression returning general objects. */ private class ObjectCondition<T> extends ObjectBinding<T> { private final ObservableObjectValue<T> trueResult; private final T trueResultValue; private final ObservableObjectValue<T> falseResult; private final T falseResultValue; private final InvalidationListener observer; private ObjectCondition(final ObservableObjectValue<T> then, final ObservableObjectValue<T> otherwise) { this.trueResult = then; this.trueResultValue = null; this.falseResult = otherwise; this.falseResultValue = null; this.observer = new WhenListener(this, condition, then, otherwise); condition.addListener(observer); then.addListener(observer); otherwise.addListener(observer); } private ObjectCondition(final T then, final ObservableObjectValue<T> otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = otherwise; this.falseResultValue = null; this.observer = new WhenListener(this, condition, null, otherwise); condition.addListener(observer); otherwise.addListener(observer); } private ObjectCondition(final ObservableObjectValue<T> then, final T otherwise) { this.trueResult = then; this.trueResultValue = null; this.falseResult = null; this.falseResultValue = otherwise; this.observer = new WhenListener(this, condition, then, null); condition.addListener(observer); then.addListener(observer); } private ObjectCondition(final T then, final T otherwise) { this.trueResult = null; this.trueResultValue = then; this.falseResult = null; this.falseResultValue = otherwise; this.observer = null; super.bind(condition); } @Override protected T computeValue() { final boolean conditionValue = condition.get(); Logging.getLogger().finest("Condition of ternary binding expression was evaluated: {0}", conditionValue); return conditionValue ? (trueResult != null ? trueResult.get() : trueResultValue) : (falseResult != null ? falseResult.get() : falseResultValue); } @Override public void dispose() { if (observer == null) { super.unbind(condition); } else { condition.removeListener(observer); if (trueResult != null) { trueResult.removeListener(observer); } if (falseResult != null) { falseResult.removeListener(observer); } } } @Override public ObservableList<ObservableValue<?>> getDependencies() { assert condition != null; final ObservableList<ObservableValue<?>> seq = FXCollections .<ObservableValue<?>>observableArrayList(condition); if (trueResult != null) { seq.add(trueResult); } if (falseResult != null) { seq.add(falseResult); } return FXCollections.unmodifiableObservableList(seq); } } /** * An intermediate class needed while assembling the ternary expression. It * should not be used in another context. * @since JavaFX 2.0 */ public class ObjectConditionBuilder<T> { private ObservableObjectValue<T> trueResult; private T trueResultValue; private ObjectConditionBuilder(final ObservableObjectValue<T> thenValue) { this.trueResult = thenValue; } private ObjectConditionBuilder(final T thenValue) { this.trueResultValue = thenValue; } /** * Defines the {@link javafx.beans.value.ObservableObjectValue} which * value is returned by the ternary expression if the condition is * {@code false}. * * @param otherwiseValue * the value * @return the complete {@link ObjectBinding} */ public ObjectBinding<T> otherwise(final ObservableObjectValue<T> otherwiseValue) { if (otherwiseValue == null) { throw new NullPointerException("Value needs to be specified"); } if (trueResult != null) return new ObjectCondition<T>(trueResult, otherwiseValue); else return new ObjectCondition<T>(trueResultValue, otherwiseValue); } /** * Defines a constant value of the ternary expression, that is returned * if the condition is {@code false}. * * @param otherwiseValue * the value * @return the complete {@link ObjectBinding} */ public ObjectBinding<T> otherwise(final T otherwiseValue) { if (trueResult != null) return new ObjectCondition<T>(trueResult, otherwiseValue); else return new ObjectCondition<T>(trueResultValue, otherwiseValue); } } /** * Defines the {@link javafx.beans.value.ObservableObjectValue} which value * is returned by the ternary expression if the condition is {@code true}. * * @param <T> the type of the intermediate result * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public <T> ObjectConditionBuilder<T> then(final ObservableObjectValue<T> thenValue) { if (thenValue == null) { throw new NullPointerException("Value needs to be specified"); } return new ObjectConditionBuilder<T>(thenValue); } /** * Defines a constant value of the ternary expression, that is returned if * the condition is {@code true}. * * @param <T> the type of the intermediate result * @param thenValue * the value * @return the intermediate result which still requires the otherwise-branch */ public <T> ObjectConditionBuilder<T> then(final T thenValue) { return new ObjectConditionBuilder<T>(thenValue); } }