org.lambdamatic.analyzer.ast.node.FieldAccess.java Source code

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Here is the source code for org.lambdamatic.analyzer.ast.node.FieldAccess.java

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/*******************************************************************************
 * Copyright (c) 2015 Red Hat. All rights reserved. This program and the accompanying materials are
 * made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Red Hat - Initial Contribution
 *******************************************************************************/

package org.lambdamatic.analyzer.ast.node;

import org.apache.commons.lang3.reflect.FieldUtils;
import org.lambdamatic.analyzer.exception.AnalyzeException;

/**
 * A field access: {@code source.fieldName}
 * 
 * @author xcoulon
 *
 */
public class FieldAccess extends ComplexExpression {

    /** the Expression on containing the field to access (may change if it is evaluated). */
    private Expression source;

    /** the name of the accessed field. */
    private final String fieldName;

    /**
     * Full constructor
     * <p>
     * Note: the synthetic {@code id} is generated and the inversion flag is set to {@code false}.
     * </p>
     * 
     * @param sourceExpression the source containing the field to access
     * @param fieldName the name of the accessed field
     */
    public FieldAccess(final Expression sourceExpression, final String fieldName) {
        this(sourceExpression, fieldName, false);
    }

    /**
     * Full constructor
     * <p>
     * Note: the synthetic {@code id} is generated and the inversion flag is set to {@code false}.
     * </p>
     * 
     * @param sourceExpression the source containing the field to access
     * @param fieldName the name of the accessed field
     * @param inverted if this {@link FieldAccess} expression is inverted
     */
    public FieldAccess(final Expression sourceExpression, final String fieldName, final boolean inverted) {
        this(generateId(), sourceExpression, fieldName, inverted);
    }

    /**
     * Full constructor with given id.
     * 
     * @param id the synthetic id of this {@link Expression}.
     * @param sourceExpression the source {@link Expression} from which the field is accessed.
     * @param fieldName the name of the field to access
     * @param inverted the inversion flag of this {@link Expression}.
     */
    public FieldAccess(final int id, final Expression sourceExpression, final String fieldName,
            final boolean inverted) {
        super(id, inverted);
        setSourceExpression(sourceExpression);
        this.fieldName = fieldName;
    }

    private void setSourceExpression(final Expression expression) {
        this.source = expression;
        this.source.setParent(this);
    }

    @Override
    public ComplexExpression getParent() {
        return (ComplexExpression) super.getParent();
    }

    @Override
    public void accept(final ExpressionVisitor visitor) {
        this.source.accept(visitor);
        visitor.visit(this);
    }

    @Override
    public void replaceElement(final Expression oldSourceExpression, final Expression newSourceExpression) {
        if (oldSourceExpression == this.source) {
            setSourceExpression(newSourceExpression);
        }
    }

    @Override
    public boolean anyElementMatches(ExpressionType type) {
        return this.source.anyElementMatches(type);
    }

    /**
     * @return the source on containing the field to access.
     */
    public Expression getSource() {
        return this.source;
    }

    @Override
    public FieldAccess duplicate(int id) {
        return new FieldAccess(id, getSource().duplicate(), getFieldName(), isInverted());
    }

    /**
     * @return an inverted instance of the current element, only if the underlying Java type is
     *         {@link Boolean}.
     */
    @Override
    public FieldAccess inverse() {
        if (getJavaType() == Boolean.class || getJavaType() == boolean.class) {
            return new FieldAccess(this.source, this.fieldName, !isInverted());
        }
        throw new UnsupportedOperationException("Field access on '" + getFieldName() + "' with Java type '"
                + getJavaType() + "' does not support inversion.");
    }

    @Override
    public ExpressionType getExpressionType() {
        return ExpressionType.FIELD_ACCESS;
    }

    @Override
    public Class<?> getJavaType() {
        try {
            return this.source.getJavaType().getField(this.fieldName).getType();
        } catch (NoSuchFieldException | SecurityException e) {
            throw new AnalyzeException("Failed to retrieve field '" + this.fieldName + "' in " + this.source, e);
        }
    }

    /**
     * @return the fieldName.
     */
    public String getFieldName() {
        return this.fieldName;
    }

    /**
     * Returns the underlying Java field.
     */
    @Override
    public Object getValue() {
        try {
            return FieldUtils.getField(this.source.getJavaType(), getFieldName());
        } catch (IllegalArgumentException e) {
            throw new AnalyzeException(
                    "Cannot retrieve field named '" + this.fieldName + "' on class " + this.source.getJavaType(),
                    e);
        }
    }

    @Override
    public boolean canBeInverted() {
        return false;
    }

    @Override
    public String toString() {
        return this.source.toString() + "." + this.fieldName;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((getExpressionType() == null) ? 0 : getExpressionType().hashCode());
        result = prime * result + ((this.source == null) ? 0 : this.source.hashCode());
        result = prime * result + ((this.fieldName == null) ? 0 : this.fieldName.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        FieldAccess other = (FieldAccess) obj;
        if (this.source == null) {
            if (other.source != null) {
                return false;
            }
        } else if (!this.source.equals(other.source)) {
            return false;
        }
        if (this.fieldName == null) {
            if (other.fieldName != null) {
                return false;
            }
        } else if (!this.fieldName.equals(other.fieldName)) {
            return false;
        }
        return true;
    }

}