compiler/src/main/java/android/databinding/tool/expr/FieldAccessExpr.java - platform/frameworks/data-binding - Git at Google

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * 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 android.databinding.tool.expr;

 import android.databinding.tool.ext.ExtKt;
 import android.databinding.tool.Binding;
 import android.databinding.tool.BindingTarget;
 import android.databinding.tool.InverseBinding;
 import android.databinding.tool.processing.Scope;
 import android.databinding.tool.reflection.Callable;
 import android.databinding.tool.reflection.Callable.Type;
 import android.databinding.tool.reflection.ModelAnalyzer;
 import android.databinding.tool.reflection.ModelClass;
 import android.databinding.tool.reflection.ModelMethod;
 import android.databinding.tool.util.BrNameUtil;
 import android.databinding.tool.store.SetterStore;
 import android.databinding.tool.store.SetterStore.BindingGetterCall;
 import android.databinding.tool.util.L;
 import android.databinding.tool.util.Preconditions;
 import android.databinding.tool.writer.KCode;

 import java.util.List;

 public class FieldAccessExpr extends Expr {
     String mName;
     // notification name for the field. Important when we map this to a method w/ different name
     String mBrName;
     Callable mGetter;
     final boolean mIsObservableField;
     boolean mIsListener;
     boolean mIsViewAttributeAccess;

     FieldAccessExpr(Expr parent, String name) {
         super(parent);
         mName = name;
         mIsObservableField = false;
     }

     FieldAccessExpr(Expr parent, String name, boolean isObservableField) {
         super(parent);
         mName = name;
         mIsObservableField = isObservableField;
     }

     public Expr getChild() {
         return getChildren().get(0);
     }

     public Callable getGetter() {
         if (mGetter == null) {
             getResolvedType();
         }
         return mGetter;
     }

     @Override
     public String getInvertibleError() {
         if (getGetter().setterName == null) {
             return "Two-way binding cannot resolve a setter for " + getResolvedType().toJavaCode() +
                     " property '" + mName + "'";
         }
         if (!mGetter.isDynamic()) {
             return "Cannot change a final field in " + getResolvedType().toJavaCode() +
                     " property " + mName;
         }
         return null;
     }

     public int getMinApi() {
         return mGetter.getMinApi();
     }

     @Override
     public boolean isDynamic() {
         if (mGetter == null) {
             getResolvedType();
         }
         if (mGetter == null || mGetter.type == Type.METHOD) {
             return true;
         }
         // if it is static final, gone
         if (getChild().isDynamic()) {
             // if owner is dynamic, then we can be dynamic unless we are static final
             return !mGetter.isStatic() || mGetter.isDynamic();
         }

         if (mIsViewAttributeAccess) {
             return true; // must be able to invalidate this
         }

         // if owner is NOT dynamic, we can be dynamic if an only if getter is dynamic
         return mGetter.isDynamic();
     }

     public boolean hasBindableAnnotations() {
         return mGetter.canBeInvalidated();
     }

     @Override
     public Expr resolveListeners(ModelClass listener, Expr parent) {
         if (mName == null || mName.isEmpty()) {
             return this; // ObservableFields aren't listeners
         }
         final ModelClass childType = getChild().getResolvedType();
         if (getGetter() == null) {
             if (listener == null || !mIsListener) {
                 L.e("Could not resolve %s.%s as an accessor or listener on the attribute.",
                         childType.getCanonicalName(), mName);
                 return this;
             }
             getChild().getParents().remove(this);
         } else if (listener == null) {
             return this; // Not a listener, but we have a getter.
         }
         List<ModelMethod> abstractMethods = listener.getAbstractMethods();
         int numberOfAbstractMethods = abstractMethods == null ? 0 : abstractMethods.size();
         if (numberOfAbstractMethods != 1) {
             if (mGetter == null) {
                 L.e("Could not find accessor %s.%s and %s has %d abstract methods, so is" +
                                 " not resolved as a listener",
                         childType.getCanonicalName(), mName,
                         listener.getCanonicalName(), numberOfAbstractMethods);
             }
             return this;
         }

         // Look for a signature matching the abstract method
         final ModelMethod listenerMethod = abstractMethods.get(0);
         final ModelClass[] listenerParameters = listenerMethod.getParameterTypes();
         boolean isStatic = getChild() instanceof StaticIdentifierExpr;
         List<ModelMethod> methods = childType.findMethods(mName, isStatic);
         if (methods == null) {
             return this;
         }
         for (ModelMethod method : methods) {
             if (acceptsParameters(method, listenerParameters) &&
                     method.getReturnType(null).equals(listenerMethod.getReturnType(null))) {
                 resetResolvedType();
                 // replace this with ListenerExpr in parent
                 Expr listenerExpr = getModel().listenerExpr(getChild(), mName, listener,
                         listenerMethod);
                 if (parent != null) {
                     int index;
                     while ((index = parent.getChildren().indexOf(this)) != -1) {
                         parent.getChildren().set(index, listenerExpr);
                     }
                 }
                 if (getModel().mBindingExpressions.contains(this)) {
                     getModel().bindingExpr(listenerExpr);
                 }
                 getParents().remove(parent);
                 if (getParents().isEmpty()) {
                     getModel().removeExpr(this);
                 }
                 return listenerExpr;
             }
         }

         if (mGetter == null) {
             L.e("Listener class %s with method %s did not match signature of any method %s.%s",
                     listener.getCanonicalName(), listenerMethod.getName(),
                     childType.getCanonicalName(), mName);
         }
         return this;
     }

     private boolean acceptsParameters(ModelMethod method, ModelClass[] listenerParameters) {
         ModelClass[] parameters = method.getParameterTypes();
         if (parameters.length != listenerParameters.length) {
             return false;
         }
         for (int i = 0; i < parameters.length; i++) {
             if (!parameters[i].isAssignableFrom(listenerParameters[i])) {
                 return false;
             }
         }
         return true;
     }

     @Override
     protected List<Dependency> constructDependencies() {
         final List<Dependency> dependencies = constructDynamicChildrenDependencies();
         for (Dependency dependency : dependencies) {
             if (dependency.getOther() == getChild()) {
                 dependency.setMandatory(true);
             }
         }
         return dependencies;
     }

     @Override
     protected String computeUniqueKey() {
         if (mIsObservableField) {
             return addTwoWay(join(mName, "..", super.computeUniqueKey()));
         }
         return addTwoWay(join(mName, ".", super.computeUniqueKey()));
     }

     public String getName() {
         return mName;
     }

     public String getBrName() {
         if (mIsListener) {
             return null;
         }
         try {
             Scope.enter(this);
             Preconditions.checkNotNull(mGetter, "cannot get br name before resolving the getter");
             return mBrName;
         } finally {
             Scope.exit();
         }
     }

     @Override
     public void updateExpr(ModelAnalyzer modelAnalyzer) {
         try {
             Scope.enter(this);
             resolveType(modelAnalyzer);
             super.updateExpr(modelAnalyzer);
         } finally {
             Scope.exit();
         }
     }

     @Override
     protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
         if (mIsListener) {
             return modelAnalyzer.findClass(Object.class);
         }
         if (mGetter == null) {
             Expr child = getChild();
             child.getResolvedType();
             boolean isStatic = child instanceof StaticIdentifierExpr;
             ModelClass resolvedType = child.getResolvedType();
             L.d("resolving %s. Resolved class type: %s", this, resolvedType);

             mGetter = resolvedType.findGetterOrField(mName, isStatic);

             if (mGetter == null) {
                 mIsListener = resolvedType.findMethods(mName, isStatic) != null;
                 if (!mIsListener) {
                     L.e("Could not find accessor %s.%s", resolvedType.getCanonicalName(), mName);
                 }
                 return modelAnalyzer.findClass(Object.class);
             }

             if (mGetter.isStatic() && !isStatic) {
                 // found a static method on an instance. register a new one
                 child.getParents().remove(this);
                 getChildren().remove(child);
                 StaticIdentifierExpr staticId = getModel().staticIdentifierFor(resolvedType);
                 getChildren().add(staticId);
                 staticId.getParents().add(this);
                 child = getChild(); // replace the child for the next if stmt
             }

             if (mGetter.resolvedType.isObservableField()) {
                 // Make this the ".get()" and add an extra field access for the observable field
                 child.getParents().remove(this);
                 getChildren().remove(child);

                 FieldAccessExpr observableField = getModel().observableField(child, mName);
                 observableField.mGetter = mGetter;

                 getChildren().add(observableField);
                 observableField.getParents().add(this);
                 mGetter = mGetter.resolvedType.findGetterOrField("", false);
                 mName = "";
                 mBrName = ExtKt.br(mName);
             } else if (hasBindableAnnotations()) {
                 mBrName = ExtKt.br(BrNameUtil.brKey(mGetter));
             }
         }
         return mGetter.resolvedType;
     }

     @Override
     public Expr resolveTwoWayExpressions(Expr parent) {
         final Expr child = getChild();
         if (!(child instanceof ViewFieldExpr)) {
             return this;
         }
         final ViewFieldExpr expr = (ViewFieldExpr) child;
         final BindingTarget bindingTarget = expr.getBindingTarget();

         // This is a binding to a View's attribute, so look for matching attribute
         // on that View's BindingTarget. If there is an expression, we simply replace
         // the binding with that binding expression.
         for (Binding binding : bindingTarget.getBindings()) {
             if (attributeMatchesName(binding.getName(), mName)) {
                 final Expr replacement = binding.getExpr();
                 replaceExpression(parent, replacement);
                 return replacement;
             }
         }

         // There was no binding expression to bind to. This should be a two-way binding.
         // This is a synthesized two-way binding because we must capture the events from
         // the View and change the value when the target View's attribute changes.
         final SetterStore setterStore = SetterStore.get(ModelAnalyzer.getInstance());
         final ModelClass targetClass = expr.getResolvedType();
         BindingGetterCall getter = setterStore.getGetterCall(mName, targetClass, null, null);
         if (getter == null) {
             getter = setterStore.getGetterCall("android:" + mName, targetClass, null, null);
             if (getter == null) {
                 L.e("Could not resolve the two-way binding attribute '%s' on type '%s'",
                         mName, targetClass);
             }
         }
         InverseBinding inverseBinding = null;
         for (Binding binding : bindingTarget.getBindings()) {
             final Expr testExpr = binding.getExpr();
             if (testExpr instanceof TwoWayListenerExpr &&
                     getter.getEventAttribute().equals(binding.getName())) {
                 inverseBinding = ((TwoWayListenerExpr) testExpr).mInverseBinding;
                 break;
             }
         }
         if (inverseBinding == null) {
             inverseBinding = bindingTarget.addInverseBinding(mName, getter);
         }
         inverseBinding.addChainedExpression(this);
         mIsViewAttributeAccess = true;
         enableDirectInvalidation();
         return this;
     }

     private static boolean attributeMatchesName(String attribute, String field) {
         int colonIndex = attribute.indexOf(':');
         return attribute.substring(colonIndex + 1).equals(field);
     }

     private void replaceExpression(Expr parent, Expr replacement) {
         if (parent != null) {
             List<Expr> children = parent.getChildren();
             int index;
             while ((index = children.indexOf(this)) >= 0) {
                 children.set(index, replacement);
                 replacement.getParents().add(parent);
             }
             while (getParents().remove(parent)) {
                 // just remove all copies of parent.
             }
         }
         if (getParents().isEmpty()) {
             getModel().removeExpr(this);
         }
     }

     @Override
     protected String asPackage() {
         String parentPackage = getChild().asPackage();
         return parentPackage == null ? null : parentPackage + "." + mName;
     }

     @Override
     protected KCode generateCode(boolean expand) {
         KCode code = new KCode();
         if (expand) {
             String defaultValue = ModelAnalyzer.getInstance().getDefaultValue(
                     getResolvedType().toJavaCode());
             code.app("(", getChild().toCode(true))
                     .app(" == null) ? ")
                     .app(defaultValue)
                     .app(" : ");
         }
         code.app("", getChild().toCode(expand)).app(".");
         if (getGetter().type == Callable.Type.FIELD) {
             return code.app(getGetter().name);
         } else {
             return code.app(getGetter().name).app("()");
         }
     }

     @Override
     public KCode toInverseCode(KCode value) {
         if (mGetter.setterName == null) {
             throw new IllegalStateException("There is no inverse for " + toCode().generate());
         }
         KCode castValue = new KCode("(").app(getResolvedType().toJavaCode() + ")(", value).app(")");
         String type = getChild().getResolvedType().toJavaCode();
         KCode code = new KCode("targetObj_.");
         if (getGetter().type == Callable.Type.FIELD) {
             code.app(getGetter().setterName).app(" = ", castValue).app(";");
         } else {
             code.app(getGetter().setterName).app("(", castValue).app(")").app(";");
         }
         return new KCode()
                 .app("final ")
                 .app(type)
                 .app(" targetObj_ = ", getChild().toCode(true))
                 .app(";")
                 .nl(new KCode("if (targetObj_ != null) {"))
                 .tab(code)
                 .nl(new KCode("}"));
     }
 }
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* 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 android.databinding.tool.expr;

	import android.databinding.tool.ext.ExtKt;
	import android.databinding.tool.Binding;
	import android.databinding.tool.BindingTarget;
	import android.databinding.tool.InverseBinding;
	import android.databinding.tool.processing.Scope;
	import android.databinding.tool.reflection.Callable;
	import android.databinding.tool.reflection.Callable.Type;
	import android.databinding.tool.reflection.ModelAnalyzer;
	import android.databinding.tool.reflection.ModelClass;
	import android.databinding.tool.reflection.ModelMethod;
	import android.databinding.tool.util.BrNameUtil;
	import android.databinding.tool.store.SetterStore;
	import android.databinding.tool.store.SetterStore.BindingGetterCall;
	import android.databinding.tool.util.L;
	import android.databinding.tool.util.Preconditions;
	import android.databinding.tool.writer.KCode;

	import java.util.List;

	public class FieldAccessExpr extends Expr {
	String mName;
	// notification name for the field. Important when we map this to a method w/ different name
	String mBrName;
	Callable mGetter;
	final boolean mIsObservableField;
	boolean mIsListener;
	boolean mIsViewAttributeAccess;

	FieldAccessExpr(Expr parent, String name) {
	super(parent);
	mName = name;
	mIsObservableField = false;
	}

	FieldAccessExpr(Expr parent, String name, boolean isObservableField) {
	super(parent);
	mName = name;
	mIsObservableField = isObservableField;
	}

	public Expr getChild() {
	return getChildren().get(0);
	}

	public Callable getGetter() {
	if (mGetter == null) {
	getResolvedType();
	}
	return mGetter;
	}

	@Override
	public String getInvertibleError() {
	if (getGetter().setterName == null) {
	return "Two-way binding cannot resolve a setter for " + getResolvedType().toJavaCode() +
	" property '" + mName + "'";
	}
	if (!mGetter.isDynamic()) {
	return "Cannot change a final field in " + getResolvedType().toJavaCode() +
	" property " + mName;
	}
	return null;
	}

	public int getMinApi() {
	return mGetter.getMinApi();
	}

	@Override
	public boolean isDynamic() {
	if (mGetter == null) {
	getResolvedType();
	}
	if (mGetter == null \|\| mGetter.type == Type.METHOD) {
	return true;
	}
	// if it is static final, gone
	if (getChild().isDynamic()) {
	// if owner is dynamic, then we can be dynamic unless we are static final
	return !mGetter.isStatic() \|\| mGetter.isDynamic();
	}

	if (mIsViewAttributeAccess) {
	return true; // must be able to invalidate this
	}

	// if owner is NOT dynamic, we can be dynamic if an only if getter is dynamic
	return mGetter.isDynamic();
	}

	public boolean hasBindableAnnotations() {
	return mGetter.canBeInvalidated();
	}

	@Override
	public Expr resolveListeners(ModelClass listener, Expr parent) {
	if (mName == null \|\| mName.isEmpty()) {
	return this; // ObservableFields aren't listeners
	}
	final ModelClass childType = getChild().getResolvedType();
	if (getGetter() == null) {
	if (listener == null \|\| !mIsListener) {
	L.e("Could not resolve %s.%s as an accessor or listener on the attribute.",
	childType.getCanonicalName(), mName);
	return this;
	}
	getChild().getParents().remove(this);
	} else if (listener == null) {
	return this; // Not a listener, but we have a getter.
	}
	List<ModelMethod> abstractMethods = listener.getAbstractMethods();
	int numberOfAbstractMethods = abstractMethods == null ? 0 : abstractMethods.size();
	if (numberOfAbstractMethods != 1) {
	if (mGetter == null) {
	L.e("Could not find accessor %s.%s and %s has %d abstract methods, so is" +
	" not resolved as a listener",
	childType.getCanonicalName(), mName,
	listener.getCanonicalName(), numberOfAbstractMethods);
	}
	return this;
	}

	// Look for a signature matching the abstract method
	final ModelMethod listenerMethod = abstractMethods.get(0);
	final ModelClass[] listenerParameters = listenerMethod.getParameterTypes();
	boolean isStatic = getChild() instanceof StaticIdentifierExpr;
	List<ModelMethod> methods = childType.findMethods(mName, isStatic);
	if (methods == null) {
	return this;
	}
	for (ModelMethod method : methods) {
	if (acceptsParameters(method, listenerParameters) &&
	method.getReturnType(null).equals(listenerMethod.getReturnType(null))) {
	resetResolvedType();
	// replace this with ListenerExpr in parent
	Expr listenerExpr = getModel().listenerExpr(getChild(), mName, listener,
	listenerMethod);
	if (parent != null) {
	int index;
	while ((index = parent.getChildren().indexOf(this)) != -1) {
	parent.getChildren().set(index, listenerExpr);
	}
	}
	if (getModel().mBindingExpressions.contains(this)) {
	getModel().bindingExpr(listenerExpr);
	}
	getParents().remove(parent);
	if (getParents().isEmpty()) {
	getModel().removeExpr(this);
	}
	return listenerExpr;
	}
	}

	if (mGetter == null) {
	L.e("Listener class %s with method %s did not match signature of any method %s.%s",
	listener.getCanonicalName(), listenerMethod.getName(),
	childType.getCanonicalName(), mName);
	}
	return this;
	}

	private boolean acceptsParameters(ModelMethod method, ModelClass[] listenerParameters) {
	ModelClass[] parameters = method.getParameterTypes();
	if (parameters.length != listenerParameters.length) {
	return false;
	}
	for (int i = 0; i < parameters.length; i++) {
	if (!parameters[i].isAssignableFrom(listenerParameters[i])) {
	return false;
	}
	}
	return true;
	}

	@Override
	protected List<Dependency> constructDependencies() {
	final List<Dependency> dependencies = constructDynamicChildrenDependencies();
	for (Dependency dependency : dependencies) {
	if (dependency.getOther() == getChild()) {
	dependency.setMandatory(true);
	}
	}
	return dependencies;
	}

	@Override
	protected String computeUniqueKey() {
	if (mIsObservableField) {
	return addTwoWay(join(mName, "..", super.computeUniqueKey()));
	}
	return addTwoWay(join(mName, ".", super.computeUniqueKey()));
	}

	public String getName() {
	return mName;
	}

	public String getBrName() {
	if (mIsListener) {
	return null;
	}
	try {
	Scope.enter(this);
	Preconditions.checkNotNull(mGetter, "cannot get br name before resolving the getter");
	return mBrName;
	} finally {
	Scope.exit();
	}
	}

	@Override
	public void updateExpr(ModelAnalyzer modelAnalyzer) {
	try {
	Scope.enter(this);
	resolveType(modelAnalyzer);
	super.updateExpr(modelAnalyzer);
	} finally {
	Scope.exit();
	}
	}

	@Override
	protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
	if (mIsListener) {
	return modelAnalyzer.findClass(Object.class);
	}
	if (mGetter == null) {
	Expr child = getChild();
	child.getResolvedType();
	boolean isStatic = child instanceof StaticIdentifierExpr;
	ModelClass resolvedType = child.getResolvedType();
	L.d("resolving %s. Resolved class type: %s", this, resolvedType);

	mGetter = resolvedType.findGetterOrField(mName, isStatic);

	if (mGetter == null) {
	mIsListener = resolvedType.findMethods(mName, isStatic) != null;
	if (!mIsListener) {
	L.e("Could not find accessor %s.%s", resolvedType.getCanonicalName(), mName);
	}
	return modelAnalyzer.findClass(Object.class);
	}

	if (mGetter.isStatic() && !isStatic) {
	// found a static method on an instance. register a new one
	child.getParents().remove(this);
	getChildren().remove(child);
	StaticIdentifierExpr staticId = getModel().staticIdentifierFor(resolvedType);
	getChildren().add(staticId);
	staticId.getParents().add(this);
	child = getChild(); // replace the child for the next if stmt
	}

	if (mGetter.resolvedType.isObservableField()) {
	// Make this the ".get()" and add an extra field access for the observable field
	child.getParents().remove(this);
	getChildren().remove(child);

	FieldAccessExpr observableField = getModel().observableField(child, mName);
	observableField.mGetter = mGetter;

	getChildren().add(observableField);
	observableField.getParents().add(this);
	mGetter = mGetter.resolvedType.findGetterOrField("", false);
	mName = "";
	mBrName = ExtKt.br(mName);
	} else if (hasBindableAnnotations()) {
	mBrName = ExtKt.br(BrNameUtil.brKey(mGetter));
	}
	}
	return mGetter.resolvedType;
	}

	@Override
	public Expr resolveTwoWayExpressions(Expr parent) {
	final Expr child = getChild();
	if (!(child instanceof ViewFieldExpr)) {
	return this;
	}
	final ViewFieldExpr expr = (ViewFieldExpr) child;
	final BindingTarget bindingTarget = expr.getBindingTarget();

	// This is a binding to a View's attribute, so look for matching attribute
	// on that View's BindingTarget. If there is an expression, we simply replace
	// the binding with that binding expression.
	for (Binding binding : bindingTarget.getBindings()) {
	if (attributeMatchesName(binding.getName(), mName)) {
	final Expr replacement = binding.getExpr();
	replaceExpression(parent, replacement);
	return replacement;
	}
	}

	// There was no binding expression to bind to. This should be a two-way binding.
	// This is a synthesized two-way binding because we must capture the events from
	// the View and change the value when the target View's attribute changes.
	final SetterStore setterStore = SetterStore.get(ModelAnalyzer.getInstance());
	final ModelClass targetClass = expr.getResolvedType();
	BindingGetterCall getter = setterStore.getGetterCall(mName, targetClass, null, null);
	if (getter == null) {
	getter = setterStore.getGetterCall("android:" + mName, targetClass, null, null);
	if (getter == null) {
	L.e("Could not resolve the two-way binding attribute '%s' on type '%s'",
	mName, targetClass);
	}
	}
	InverseBinding inverseBinding = null;
	for (Binding binding : bindingTarget.getBindings()) {
	final Expr testExpr = binding.getExpr();
	if (testExpr instanceof TwoWayListenerExpr &&
	getter.getEventAttribute().equals(binding.getName())) {
	inverseBinding = ((TwoWayListenerExpr) testExpr).mInverseBinding;
	break;
	}
	}
	if (inverseBinding == null) {
	inverseBinding = bindingTarget.addInverseBinding(mName, getter);
	}
	inverseBinding.addChainedExpression(this);
	mIsViewAttributeAccess = true;
	enableDirectInvalidation();
	return this;
	}

	private static boolean attributeMatchesName(String attribute, String field) {
	int colonIndex = attribute.indexOf(':');
	return attribute.substring(colonIndex + 1).equals(field);
	}

	private void replaceExpression(Expr parent, Expr replacement) {
	if (parent != null) {
	List<Expr> children = parent.getChildren();
	int index;
	while ((index = children.indexOf(this)) >= 0) {
	children.set(index, replacement);
	replacement.getParents().add(parent);
	}
	while (getParents().remove(parent)) {
	// just remove all copies of parent.
	}
	}
	if (getParents().isEmpty()) {
	getModel().removeExpr(this);
	}
	}

	@Override
	protected String asPackage() {
	String parentPackage = getChild().asPackage();
	return parentPackage == null ? null : parentPackage + "." + mName;
	}

	@Override
	protected KCode generateCode(boolean expand) {
	KCode code = new KCode();
	if (expand) {
	String defaultValue = ModelAnalyzer.getInstance().getDefaultValue(
	getResolvedType().toJavaCode());
	code.app("(", getChild().toCode(true))
	.app(" == null) ? ")
	.app(defaultValue)
	.app(" : ");
	}
	code.app("", getChild().toCode(expand)).app(".");
	if (getGetter().type == Callable.Type.FIELD) {
	return code.app(getGetter().name);
	} else {
	return code.app(getGetter().name).app("()");
	}
	}

	@Override
	public KCode toInverseCode(KCode value) {
	if (mGetter.setterName == null) {
	throw new IllegalStateException("There is no inverse for " + toCode().generate());
	}
	KCode castValue = new KCode("(").app(getResolvedType().toJavaCode() + ")(", value).app(")");
	String type = getChild().getResolvedType().toJavaCode();
	KCode code = new KCode("targetObj_.");
	if (getGetter().type == Callable.Type.FIELD) {
	code.app(getGetter().setterName).app(" = ", castValue).app(";");
	} else {
	code.app(getGetter().setterName).app("(", castValue).app(")").app(";");
	}
	return new KCode()
	.app("final ")
	.app(type)
	.app(" targetObj_ = ", getChild().toCode(true))
	.app(";")
	.nl(new KCode("if (targetObj_ != null) {"))
	.tab(code)
	.nl(new KCode("}"));
	}
	}